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Standard Methods for the Examination of Water and Wastewater Part 4000 INORGANIC NONMETALLIC CONSTITUENTS 4010 INTRODUCTION The analytical methods included in this part make use of classical wet chemical techniques and their automated variations and such modern instrumental techniques as ion chromatography Methods that measure various forms of chlorine, nitrogen, and phosphorus are presented The procedures are intended for use in the assessment and control of receiving water quality, the treatment and supply of potable water, and the measurement of operation and process efficiency in wastewater treatment The methods also are appropriate and applicable in evaluation of environmental water-quality concerns The introduction to each procedure contains reference to special field sampling conditions, appropriate sample containers, proper procedures for sampling and storage, and the applicability of the method 4020 QUALITY ASSURANCE/QUALITY CONTROL 4020 A Introduction Without quality control results there is no confidence in analytical results reported from tests As described in Part 1000 and Section 3020, essential quality control measurements include: method calibration, standardization of reagents, assessment of individual capability to perform the analysis, performance of blind check samples, determination of the sensitivity of the test procedure (method detection level), and daily evaluation of bias, precision, and the presence of laboratory contamination or other analytical interference Details of these procedures, expected ranges of results, and frequency of performance should be formalized in a written Quality Assurance Manual and Standard Operating Procedures For a number of the procedures contained in Part 4000, the traditional determination of bias using a known addition to either a sample or a blank, is not possible Examples of these procedures include pH, dissolved oxygen, residual chlorine, and carbon dioxide The inability to perform a reliable known addition does not relieve the analyst of the responsibility for evaluating test bias Analysts are encouraged to purchase certified ready-made solutions of known levels of these constituents as a means of measuring bias In any situation, evaluate precision through analysis of sample duplicates Participate in a regular program (at a minimum, annually, and preferably semi-annually) of proficiency testing (PT)/performance evaluation (PE) studies The information and analytical confidence gained in the routine performance of the studies more than offset any costs associated © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater with these studies An unacceptable result on a PT study sample is often the first indication that a test protocol is not being followed successfully Investigate circumstances fully to find the cause Within many jurisdictions, participation in PT studies is a required part of laboratory certification Many of the methods contained in Part 4000 include specific quality-control procedures These are considered to be the minimum quality controls necessary to successful performance of the method Additional quality control procedures can and should be used Section 4020B describes a number of QC procedures that are applicable to many of the methods 4020 B Quality Control Practices Initial Quality Control See Section 3020B.1 Calibration See Section 3020B.2 Most methods for inorganic nonmetals not have wide dynamic ranges Standards for initial calibration therefore should be spaced more closely than one order of magnitude under these circumstances Verify calibration by analyzing a midpoint or lower calibration standard and blank as directed Alternatively, verify calibration with two standards, one near the low end and one near the high end, if the blank is used to zero the instrument Batch Quality Control See Section 3020B.3a through d 4110 DETERMINATION OF ANIONS BY ION CHROMATOGRAPHY*#(1) 4110 A Introduction Because of rapid changes in technology, this section is currently undergoing substantial revision Determination of the common anions such as bromide, chloride, fluoride, nitrate, nitrite, phosphate, and sulfate often is desirable to characterize a water and/or to assess the need for specific treatment Although conventional colorimetric, electrometric, or titrimetric methods are available for determining individual anions, only ion chromatography provides a single instrumental technique that may be used for their rapid, sequential measurement Ion chromatography eliminates the need to use hazardous reagents and it effectively distinguishes among the halides (Br–, Cl–, and F–) and the oxy-ions (SO32–, SO42– or NO2–, NO3–) This method is applicable, after filtration to remove particles larger than 0.2 àm, to surface, â Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater ground, and wastewaters as well as drinking water Some industrial process waters, such as boiler water and cooling water, also may be analyzed by this method 4110 B Ion Chromatography with Chemical Suppression of Eluent Conductivity General Discussion a Principle: A water sample is injected into a stream of carbonate-bicarbonate eluent and passed through a series of ion exchangers The anions of interest are separated on the basis of their relative affinities for a low capacity, strongly basic anion exchanger (guard and separator columns) The separated anions are directed through a hollow fiber cation exchanger membrane (fiber suppressor) or micromembrane suppressor bathed in continuously flowing strongly acid solution (regenerant solution) In the suppressor the separated anions are converted to their highly conductive acid forms and the carbonate-bicarbonate eluent is converted to weakly conductive carbonic acid The separated anions in their acid forms are measured by conductivity They are identified on the basis of retention time as compared to standards Quantitation is by measurement of peak area or peak height b Interferences: Any substance that has a retention time coinciding with that of any anion to be determined and produces a detector response will interfere For example, relatively high concentrations of low-molecular-weight organic acids interfere with the determination of chloride and fluoride by isocratic analyses A high concentration of any one ion also interferes with the resolution, and sometimes retention, of others Sample dilution or gradient elution overcomes many interferences To resolve uncertainties of identification or quantitation use the method of known additions Spurious peaks may result from contaminants in reagent water, glassware, or sample processing apparatus Because small sample volumes are used, scrupulously avoid contamination Modifications such as preconcentration of samples, gradient elution, or reinjection of portions of the eluted sample may alleviate some interferences but require individual validation for precision and bias c Minimum detectable concentration: The minimum detectable concentration of an anion is a function of sample size and conductivity scale used Generally, minimum detectable concentrations are near 0.1 mg/L for Br–, Cl–, NO3–, NO2–, PO43–, and SO42– with a 100-µL sample loop and a 10-µS/cm full-scale setting on the conductivity detector Lower values may be achieved by using a higher scale setting, an electronic integrator, or a larger sample size d Limitations: This method is not recommended for the determination of F– in unknown matrices Equivalency studies have indicated positive or negative bias and poor precision in some samples Recent interlaboratory studies show acceptable results Two effects are common: first, F– is difficult to quantitate at low concentrations because of the major negative contribution of the ‘‘water dip’’ (corresponding to the elution of water); second, the simple organic acids (formic, carbonic, etc.) elute close to fluoride and will interfere Determine precision and bias © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater before analyzing samples F– can be determined accurately by ion chromatography using special techniques such as dilute eluent or gradient elution using an NaOH eluent or alternative columns Apparatus a Ion chromatograph, including an injection valve, a sample loop, guard column, separator column, and fiber or membrane suppressors, a temperature-compensated small-volume conductivity cell and detector (6 µL or less), and a strip-chart recorder capable of full-scale response of s or less An electronic peak integrator is optional Use an ion chromatograph capable of delivering to mL eluent/min at a pressure of 1400 to 6900 kPa b Anion separator column, with styrene divinylbenzene-based low-capacity pellicular anion-exchange resin capable of resolving Br–, Cl–, NO3–, NO2–, PO43–, and SO42–.*#(2) c Guard column, identical to separator column†#(3) to protect separator column from fouling by particulates or organics d Fiber suppressor or membrane suppressor:‡#(4) Cation-exchange membrane capable of continuously converting eluent and separated anions to their acid forms Alternatively, use continuously regenerated suppression systems Reagents a Deionized or distilled water free from interferences at the minimum detection limit of each constituent, filtered through a 0.2-µm membrane filter to avoid plugging columns, and having a conductance of < 0.1 µS/cm b Eluent solution, sodium bicarbonate-sodium carbonate, 0.0017M NaHCO3-0.0018M Na2CO3: Dissolve 0.5712 g NaHCO3 and 0.7632 g Na2CO3 in water and dilute to L c Regenerant solution, H2SO4, 0.025N: Dilute 2.8 mL conc H2SO4 to L d Standard anion solutions, 1000 mg/L: Prepare a series of standard anion solutions by weighing the indicated amount of salt, dried to a constant weight at 105°C, to 1000 mL Store in plastic bottles in a refrigerator; these solutions are stable for at least month Verify stability Anion§ Amount g/L Salt Cl– NaCl 1.6485 Br– NaBr 1.2876 NO3– NaNO3 1.3707 (226 mg NO3–-N/L) NO2– NaNO2 1.4998i (304 mg NO2–-N/L) PO43– KH2PO4 1.4330 (326 mg PO43–-P/L © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater Anion§ Salt SO42– K2SO4 Amount g/L 1.8141 § Expressed as compound i Do not oven-dry, but dry to constant weight in a desiccator e Combined working standard solution, high range: Combine 12 mL of standard anion solutions, 1000 mg/L (¶ 3d) of NO2–, NO3–, HPO42–, and Br–, 20 mL of Cl–, and 80 mL of SO42– Dilute to 1000 mL and store in a plastic bottle protected from light Solution contains 12 mg/L each of NO2–, NO3–, HPO42–, and Br–, 20 mg/L of Cl–, and 80 mg/L of SO42– Prepare fresh daily f Combined working standard solution, low range: Dilute 25 mL of the high-range mixture (¶ 3e) to 100 mL and store in a plastic bottle protected from light Solution contains mg/L each of NO2–, NO3–, HPO42–, and Br–, mg/L Cl–, and 20 mg/L of SO42– Prepare fresh daily g Alternative combined working standard solutions: Prepare appropriate combinations according to anion concentration to be determined If NO2– and PO43– are not included, the combined working standard is stable for month Dilute solutions containing NO2– and PO43– must be made daily Procedure a System equilibration: Turn on ion chromatograph and adjust eluent flow rate to approximate the separation achieved in Figure 4110:1 (about mL/min) Adjust detector to desired setting (usually 10 to 30 µS) and let system come to equilibrium (15 to 20 min) A stable base line indicates equilibrium conditions Adjust detector offset to zero out eluent conductivity; with the fiber or membrane suppressor adjust the regeneration flow rate to maintain stability, usually 2.5 to mL/min b Calibration: Inject standards containing a single anion or a mixture and determine approximate retention times Observed times vary with conditions but if standard eluent and anion separator column are used, retention always is in the order F–, Cl–, NO2–, Br–, NO3–, HPO42–, and SO42– Inject at least three different concentrations (one near the minimum reporting limit) for each anion to be measured and construct a calibration curve by plotting peak height or area against concentration on linear graph paper Recalibrate whenever the detector setting, eluent, or regenerant is changed To minimize the effect of the ‘‘water dip’’##(5) on F– analysis, analyze standards that bracket the expected result or eliminate the water dip by diluting the sample with eluent or by adding concentrated eluent to the sample to give the same © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater HCO3–/CO32– concentration as in the eluent If sample adjustments are made, adjust standards and blanks identically If linearity is established for a given detector setting, single standard calibration is acceptable Record peak height or area and retention time for calculation of the calibration factor, F However, a calibration curve will result in better precision and bias HPO42– is nonlinear below 1.0 mg/L c Sample analysis: Remove sample particulates, if necessary, by filtering through a prewashed 0.2-µm-pore-diam membrane filter Using a prewashed syringe of to 10 mL capacity equipped with a male luer fitting inject sample or standard Inject enough sample to flush sample loop several times: for 0.1 mL sample loop inject at least mL Switch ion chromatograph from load to inject mode and record peak heights and retention times on strip chart recorder After the last peak (SO42–) has appeared and the conductivity signal has returned to base line, another sample can be injected Calculations Calculate concentration of each anion, in milligrams per liter, by referring to the appropriate calibration curve Alternatively, when the response is shown to be linear, use the following equation: C=H×F×D where: C= H= F= D= mg anion/L, peak height or area, response factor = concentration of standard/height (or area) of standard, and dilution factor for those samples requiring dilution Quality Control See Section 4020 for minimum QC guidelines Precision and Bias The data in Table 4110:I, Table 4110:II, Table 4110:III, Table 4110:IV, Table 4110:V, Table 4110:VI, and Table 4110:VII were produced in a joint validation study with EPA and ASTM participation Nineteen laboratories participated and used known additions of six prepared concentrates in three waters (reagent, waste, and drinking) of their choice Bibliography SMALL, H., T STEVENS & W BAUMAN 1975 Novel ion exchange chromatographic method using conductimetric detection Anal Chem 47:1801 JENKE, D 1981 Anion peak migration in ion chromatography Anal Chem 53:1536 BYNUM, M.I., S TYREE & W WEISER 1981 Effect of major ions on the determination of trace © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater ions by ion chromatography Anal Chem 53: 1935 WEISS, J 1986 Handbook of Ion Chromatography E.L Johnson, ed Dionex Corp., Sunnyvale, Calif PFAFF, J.D., C.A BROCKHOFF & J.W O’DELL 1994 The Determination of Inorganic Anions in Water by Ion Chromatography Method 300.0A, U.S Environmental Protection Agency, Environmental Monitoring Systems Lab., Cincinnati, Ohio 4110 C Single-Column Ion Chromatography with Electronic Suppression of Eluent Conductivity and Conductimetric Detection General Discussion a Principle: A small portion of a filtered, homogeneous, aqueous sample or a sample containing no particles larger than 0.45 µm is injected into an ion chromatograph The sample merges with the eluent stream and is pumped through the ion chromatographic system Anions are separated on the basis of their affinity for the active sites of the column packing material Conductivity detector readings (either peak area or peak height) are used to compute concentrations b Interferences: Any two species that have similar retention times can be considered to interfere with each other This method has potential coelution interference between short-chain acids and fluoride and chloride Solid-phase extraction cartridges can be used to retain organic acids and pass inorganic anions The interference-free solution then can be introduced into the ion chromatograph for separation This method is usable but not recommended for fluoride Acetate, formate, and carbonate interfere in determining fluoride under the conditions listed in Table 4110:VIII Filtering devices may be used to remove organic materials for fluoride measurements; simultaneously, use a lower eluent flow rate Chlorate and bromide coelute under the specified conditions Determine whether other anions in the sample coelute with the anions of interest Additional interference occurs when anions of high concentrations overlap neighboring anionic species Minimize this by sample dilution with reagent water Best separation is achieved with sample pH between and When samples are injected the eluent pH will seldom change unless the sample pH is very low Raise sample pH by adding a small amount of a hydroxide salt to enable the eluent to control pH Because method sensitivity is high, avoid contamination by reagent water and equipment Determine any background or interference due to the matrix when adding the QC sample into any matrix other than reagent water c Minimum detectable concentration: The minimum detectable concentration of an anion is a function of sample volume and the signal-to-noise ratio of the detector-recorder combination Generally, minimum detectable concentrations are about 0.1 mg/L for the anions with an © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater injection volume of 100 µL Preconcentrators or using larger injection volumes can reduce detection limits to nanogram-per-liter levels for the common anions However, coelution is a possible problem with large injection volumes Determine method detection limit for each anion of interest d Prefiltration: If particularly contaminated samples are run, prefilter before or during injection If the guard column becomes contaminated, follow manufacturer’s suggestions for cleanup Apparatus a Ion chromatograph, complete with all required accessories including syringes, analytical columns, gases, detector, and a data system Required accessories are listed below b Filter device, 0.45 µm, placed before separator column to protect it from fouling by particulates or organic constituents.*#(6) c Anion separator column, packed with low-capacity anion-exchange resin capable of resolving fluoride, chloride, nitrite, bromide, nitrate, orthophosphate, and sulfate.†#(7) d Conductivity detector, flow-through, with integral heat-exchange unit allowing automatic temperature control and with separate working and reference electrodes e Pump, constant flow rate controlled, high-pressure liquid chromatographic type, to deliver 1.5 mL/min f Data system, including one or more computer, integrator, or strip chart recorder compatible with detector output voltage g Sample injector: Either an automatic sample processor or a manual injector If manual injector is used, provide several glass syringes of > 200 µL capacity The automatic device must be compatible and able to inject a minimum sample volume of 100 µL Reagents a Reagent water: Distilled or deionized water of 18 megohm-cm resistivity containing no particles larger than 0.20 µm b Borate/gluconate concentrate: Combine 16.00 g sodium gluconate, 18.00 g boric acid, 25.00 g sodium tetraborate decahydrate, and 125 mL glycerin in 600 mL reagent water Mix and dilute to L with reagent water c Eluent solution, 0.0110M borate, 0.0015M gluconate, 12% (v/v) acetonitrile: Combine 20 mL borate/gluconate concentrate, 120 mL HPLC-grade acetonitrile, and 20 mL HPLC-grade n-butanol, and dilute to L with reagent water Use an in-line filter before the separator column to assure freedom from particulates If the base line drifts, degas eluent with an inert gas such as helium or argon d Stock standard solutions: See Section 4110B.3e e Combined working standard solutions, high-range: See Section 4110B.3e © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater f Combined working standard solutions, low-range: See Section 4110B.3 f Procedure a System equilibration: Set up ion chromatograph in accordance with the manufacturer’s directions Install guard and separator columns and begin pumping eluent until a stable base line is achieved The background conductivity of the eluent solution is 278 µS ± 10% b Calibration: Determine retention time for each anion by injecting a standard solution containing only the anion of interest and noting the time required for a peak to appear Retention times vary with operating conditions and with anion concentration Late eluters show the greatest variation The shift in retention time is inversely proportional to concentration The order of elution is shown in Figure 4110:2 Construct a calibration curve by injecting prepared standards including each anion of interest Use at least three concentrations plus a blank Cover the range of concentrations expected for samples Use one concentration near but above the method detection limit established for each anion to be measured Unless the detector’s attenuation range settings have been proven to be linear, calibrate each setting individually Construct calibration curve by plotting either peak height or peak area versus concentration If a data system is being used, make a hard copy of the calibration curve available Verify that the working calibration curve is within ± 10% of the previous value on each working day; if not, reconstruct it Also, verify when the eluent is changed and after every 20 samples If response or retention time for any anion varies from the previous value by more than ± 10%, reconstruct the curve using fresh calibration standards c Sample analysis: Inject enough sample (about two to three times the loop volume) to insure that sample loop is properly flushed Inject sample into chromatograph and let all peaks elute before injecting another sample (usually this occurs in about 20 min) Compare response in peak height or peak area and retention time to values obtained in calibration Calculation Determine the concentration of the anions of interest from the appropriate standard curve If sample dilutions were made, calculate concentration: C=A×F where: C = anion concentration, mg/L, A = mg/L from calibration curve, and F = dilution factor Quality Control a If columns other than those listed in Section 4110C.2c are used, demonstrate that the resolution of all peaks is similar to that shown in Figure 4110:2 © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater b Generate accuracy and precision data with this method by using a reference standard of known concentration prepared independently of the laboratory making the analysis Compare with data in Precision and Bias, below c Analyze a quality control sample at least every 10 samples Follow general guidelines from Section 4020 Precision and Bias Precision and bias data are given in Table 4110:IX Reference GLASER, J., D FOERST, G MCKEE, S QUAVE & W BUDDE 1981 Trace analyses for wastewater Environ Sci Technol 15:1426 4120 SEGMENTED CONTINUOUS FLOW ANALYSIS*#(8) 4120 A Introduction Background and Applications Air-segmented flow analysis (SFA) is a method that automates a large number of wet chemical analyses An SFA analyzer can be thought of as a ‘‘conveyor belt’’ system for wet chemical analysis, in which reagents are added in a ‘‘production-line’’ manner Applications have been developed to duplicate manual procedures precisely SFA was first applied to analysis of sodium and potassium in human serum, with a flame photometer as the detection device, by removing protein interferences with a selectively porous membrane (dialyzer) The advantages of segmented flow, compared to the manual method, include reduced sample and reagent consumption, improved repeatability, and minimal operator contact with hazardous materials A typical SFA system can analyze 30 to 120 samples/ h Reproducibility is enhanced by the precise timing and repeatability of the system Because of this, the chemical reactions not need to go to 100% completion Decreasing the number of manual sample/solution manipulations reduces labor costs, improves workplace safety, and improves analytical precision Complex chemistries using dangerous chemicals can be carried out in sealed systems Unstable reagents can be made up in situ An SFA analyzer uses smaller volumes of reagents and samples than manual methods, producing less chemical waste needing disposal SFA is not limited to single-phase colorimetric determinations Segmented-flow techniques often include analytical procedures such as mixing, dilution, distillation, digestion, dialysis, solvent extractions, and/or catalytic conversion In-line distillation methods are used for the determinations of ammonia, fluoride, cyanide, phenols, and other volatile compounds In-line digestion can be used for the determination of total phosphorous, total cyanide, and total nitrogen © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater * See also Alkalinity, Section 2320 21 (Popup - Footnote) † Copies of the nomographs in Figure 4500-CO2:1–4, enlarged to several times the size shown here, may be obtained as a set from Standard Methods Manager, The American Water Works Association, 6666 West Quincy Ave., Denver, CO 80235 22 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 23 (Popup - Footnote) * Orion Model 94-06A or equivalent 24 (Popup - Footnote) * Orion Model 95-10, EIL Model 8002-2, Beckman Model 39565, or equivalent 25 (Popup - Footnote) * Amberlite® XAD-7, or equivalent 26 (Popup - Footnote) * Teflon or equivalent 27 (Popup - Footnote) † MICRO DIST, Lachat Instruments, Milwaukee, WI 28 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 29 (Popup - Footnote) * Titration may be delayed up to 10 without appreciable error if H3PO4 is not added until immediately before titration 30 (Popup - Footnote) * Kimax 17110-F, mL, Kimble Products, Box 1035, Toledo, OH, or equivalent 31 (Popup - Footnote) * Eastman chemical No 7102 or equivalent 32 (Popup - Footnote) † Available from Gallard-Schlesinger Chemical Mfg Corp., 584 Mineola Avenue, Carle Place, NY 11514, or equivalent 33 (Popup - Footnote) * Aldrich No 17, 753-9, Aldrich Chemical Company, Inc., 1001 West St Paul Ave., Milwaukee, WI 53233, or equivalent 34 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 35 (Popup - Footnote) * Brij 35, available from ICI Americas, Wilmington, DE, or equivalent 36 (Popup - Footnote) * Teflon or equivalent 37 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater 38 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 39 (Popup - Footnote) * Also known as 1,2 cyclohexylenedinitrilotetraacetic acid 40 (Popup - Footnote) * J.T Baker Catalog number J-112 or equivalent 41 (Popup - Footnote) † Brij-35, available from ICI Americas, Wilmington, DE, or equivalent 42 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1996 43 (Popup - Footnote) † p designates −log10 of a number 44 (Popup - Footnote) * Teflon or equivalent 45 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 46 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 47 (Popup - Footnote) * Eastman chemical No 3651 or equivalent 48 (Popup - Footnote) † Oxone, E.I duPont de Nemours and Co., Inc., Wilmington, DE, or equivalent 49 (Popup - Footnote) * Triton X-100, Catalog No T9284, Sigma-Aldrich Corp., P.O Box 14508, St Louis, MO 63178 50 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 51 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 52 (Popup - Footnote) * 18-415, Comar, Inc., Vineland, NJ, or equivalent 53 (Popup - Footnote) † Brij-35, available from ICI Americas, Inc., Wilmington, DE, or equivalent 54 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 55 (Popup - Footnote) * Orion Model 95-12, EIL Model 8002-2, Beckman Model 39565, or equivalent 56 (Popup - Footnote) * Brij-35, available from ICI Americas, Wilmington, DE 57 (Popup - Footnote) * Teflon or equivalent © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater 58 (Popup - Footnote) † Clorox, The Clorox Company, Pleasanton, CA, or equivalent 59 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 60 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 61 (Popup - Footnote) * Orion Model 90-02, or equivalent 62 (Popup - Footnote) † Orion Model 93-07, Corning Model 476134, or equivalent 63 (Popup - Footnote) * Tudor Scientific Glass Co., 555 Edgefield Road, Belvedere, SC 29841, Cat TP-1730, or equivalent 64 (Popup - Footnote) † EM Laboratories, Inc., 500 Exec Blvd., Elmsford, NY, Cat 2001, or equivalent 65 (Popup - Footnote) * Brij-35, available from ICI Americas, Inc., Wilmington, DE, or equivalent 66 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 67 (Popup - Footnote) * Rotary kjeldahl digestion unit, Kontes, Model 551000-0000, or equivalent 68 (Popup - Footnote) † ASTM E-147 or equivalent 69 (Popup - Footnote) * Regular Clorox, The Clorox Company, Pleasanton, CA, or equivalent 70 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 71 (Popup - Footnote) * Fundamentally, the current is directly proportional to the activity of molecular oxygen.7 72 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 73 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 74 (Popup - Footnote) * GFS Chemical Co., Columbus, OH, or equivalent 75 (Popup - Footnote) * Whatman No 42 or equivalent 76 (Popup - Footnote) † Darco G60 or equivalent 77 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater 78 (Popup - Footnote) * Millipore or equivalent 79 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 80 (Popup - Footnote) * Eastman No 360 has been found satisfactory 81 (Popup - Footnote) * Teflon or equivalent 82 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 83 (Popup - Footnote) * Eastman catalog No 5672 has been found satisfactory for this purpose 84 (Popup - Footnote) * Orion 941600 or equivalent 85 (Popup - Footnote) † Orion 948201 or equivalent 86 (Popup - Footnote) ‡ EG&G Princeton Applied Research K0066, K0060, G0028, or equivalent 87 (Popup - Footnote) * Lachat Instruments MICRO DIST or equivalent 88 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1996 89 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 90 (Popup - Footnote) * ‘‘Desicote’’ (Beckman), or equivalent 91 (Popup - Footnote) * Constant weight is defined as a change of not more than 0.5 mg in two successive operations consisting of heating, cooling in desiccator, and weighing 92 (Popup - Footnote) * Hach 2100 A 93 (Popup - Footnote) * Ion-exchange resin Bio-Rex 70, 20-50 mesh, sodium form, available from Bio-Rad Laboratories, Richmond, CA 94804, or equivalent 94 (Popup - Footnote) † Eastman Organic Chemicals, Rochester, NY 14615 No 8068 3′,3′′ bis [N,N-bis(carboxymethyl)-aminolmethyl] thymolsulfonphthalein pentasodium salt 95 (Popup - Footnote) * Aldrich 24, 511-9, or equivalent 96 (Popup - Footnote) † BioRex 70 or equivalent © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater 97 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 98 (Popup - Footnote) * Nitrification Inhibitor, Formula 2533, Hach Co., Loveland, CO, or equivalent 99 (Popup - Footnote) * Some analysts have reported satisfactory results with 2-chloro-6-(trichloromethyl) pyridine (Nitrification Inhibitor, Formula 2533, Hach Co., Loveland, CO, or equivalent) 100 (Popup - Footnote) † Wheaton 2-L BOD bottle No 227580, 1000 North Tenth St., Millville, NJ, or equivalent 101 (Popup - Footnote) * Formula 2533, Hach Chemical Co., Loveland, CO, or equivalent NOTE: Some commercial formulations are not pure TCMP Check with supplier to verify compound purity and adjust dosages accordingly 102 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 103 (Popup - Footnote) * GFS Chemicals, Inc., Columbus, OH, or equivalent 104 (Popup - Footnote) * Hach Co., Bioscience, Inc., or equivalent 105 (Popup - Footnote) *APPROVED BY STANDARD METHODS COMMITTEE, 1996 106 (Popup - Footnote) *NOTE: If mercuric nitrate is used to complex the chloride, use an appropriate disposal method for the treated waste to prevent mercury contamination 107 (Popup - Footnote) †Data may be obtained from Standard Methods manager, American Water Works Association 108 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 109 (Popup - Footnote) * Westvaco or Calgon Filtrasorb 400 or equivalent 110 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 111 (Popup - Footnote) † ‘‘Solubility’’ is here used as a general description of whether or not the material can be uniformly dispersed in an aqueous phase rather than as an expression of equilibrium between a pure solute and its aqueous solution 112 (Popup - Footnote) * Whatman No or equivalent 113 (Popup - Footnote) † Whatman pre-swollen microgranular DE 52 or DE 51, or equivalent 114 (Popup - Footnote) © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater * Pump parts may be of stainless steel or TFE 115 (Popup - Footnote) † XAD-7 or equivalent 116 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 117 (Popup - Footnote) * Teflon or equivalent 118 (Popup - Footnote) † Whatman No 40 or equivalent 119 (Popup - Footnote) * Teflon or equivalent 120 (Popup - Footnote) † Whatman No 40 or equivalent 121 (Popup - Footnote) * Whatman No 40 or equivalent 122 (Popup - Footnote) † Hyflo Super-Cel, Manville Corp., or equivalent 123 (Popup - Footnote) * Whatman No 40 or equivalent 124 (Popup - Footnote) † Davidson Grade 923 or equivalent 125 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 126 (Popup - Footnote) * Corning No 3360 or equivalent 127 (Popup - Footnote) * 15-mL Corning No 36060 or equivalent 128 (Popup - Footnote) † For NPDES permit analyses, pH 10 ± 0.1 is required 129 (Popup - Footnote) *APPROVED BY STANDARD METHODS COMMITTEE, 1993 130 (Popup - Footnote) * For sources of suitable reference material, contact Standard Methods manager 131 (Popup - Footnote) † Eastman No P573 or equivalent 132 (Popup - Footnote) * Bio-Rad, AGl-X2, or equivalent 133 (Popup - Footnote) † Bio-Rad AG 50W-X8, or equivalent 134 (Popup - Footnote) ‡ For sources of suitable reference material, contact Standard Methods manager © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater 135 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 136 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1996 137 (Popup - Footnote) * Ascarite or equivalent 138 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1994 139 (Popup - Footnote) * Milli-Q, Millipore Corp., or equivalent 140 (Popup - Footnote) * Federal regulations may require a simple sum in terms of mass units/L 141 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1994 142 (Popup - Footnote) * Whatman grade 934AH; Gelman type A/E; Millipore type AP40; ED Scientific Specialties grade 161; or other products that give demonstrably equivalent results Practical filter diameters are 2.2 to 4.7 cm 143 (Popup - Footnote) * Pierce 13075 or equivalent 144 (Popup - Footnote) † Pierce 12722 or equivalent 145 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 146 (Popup - Footnote) * Model CLS 1, Tekmar, Cincinnati, OH; Brechbuhler AG, 8952 Schlieren ZH, Switzerland, available from Chromapon, Whittier, CA; or equivalent 147 (Popup - Footnote) † Rotulex Sovirel, Brechbuhler AG or equivalent 148 (Popup - Footnote) ‡ Brechbuhler AG or equivalent 149 (Popup - Footnote) § Metal Bellows Model MB-21, Sharon, MA, or equivalent 150 (Popup - Footnote) i Swagelok fittings or equivalent 151 (Popup - Footnote) # Brechbuhler AG, Chromapon, Inc., or equivalent 152 (Popup - Footnote) ** Hamilton Model 1805N electrotapered tip, Reno, NV 153 (Popup - Footnote) †† Pierce Chemical Company #13100 or equivalent © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater 154 (Popup - Footnote) ‡‡ 1-Chlorohexadecane and 1-chlorooctadecane solidify upon refrigeration Warm before removing a portion 155 (Popup - Footnote) §§ Geosmin and 2-methylisoborneol are available from Wako Bioproducts, Wako Chemicals USA, Inc., 1600 Bellwood Rd., Richmond, VA 23237, or Dalton Chemical Lab, Inc., 4700 Keele St., Suite 119, FARQ, North York, Ontario, Canada M3J 1P3 NOTE: This synthetic geosmin is racemic and includes (+)-geosmin, which has an odor intensity different from that of the natural (−) compound This precludes its use in quantitative sensory analysis; however, its GC/MS characteristics (i.e., retention time and spectrum) are the same as those of natural geosmin 156 (Popup - Footnote) i i Millipore Milli-QUV Plus or equivalent 157 (Popup - Footnote) ## A total sample volume of 900 mL is preferred to minimize foaming-over due to salt addition 158 (Popup - Footnote) *** NOTE: Because synthetic labeled geosmin is racemic, best results for the compensation of prolonged biological processes are achieved by monitoring the degradation of natural (−)-geosmin using (−)-geosmin-d3 159 (Popup - Footnote) ††† Calibration mark needs to be verified periodically 160 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1997 161 (Popup - Footnote) ** Tekmar VOCARB 4000 or equivalent 162 (Popup - Footnote) † Gas chromatographic methods are extremely sensitive to the materials used Mention of trade names by Standard Methods does not preclude the use of other existing or as-yet- undeveloped products that give demonstrably equivalent results 163 (Popup - Footnote) ‡ Supelco, Inc or equivalent 164 (Popup - Footnote) § J&W or equivalent 165 (Popup - Footnote) i Luerlok or equivalent 166 (Popup - Footnote) # Hamilton # 702 or equivalent 167 (Popup - Footnote) ** Millipore Super Q or equivalent 168 (Popup - Footnote) †† Tygon or equivalent © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater 169 (Popup - Footnote) * Tracor Model 703 or equivalent 170 (Popup - Footnote) † Luerlok or equivalent 171 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1996 172 (Popup - Footnote) * Marketed under the following trade names: ‘‘Explosimeter,’’ ‘‘Methane Gas Detector,’’ and ‘‘Methane Tester,’’ all manufactured by Mine Safety Appliance Co., Pittsburgh, PA 15235, and ‘‘J-W Combustible Gas Indicator,’’ manufactured by Bacharach Instrument Co., Mountain View, CA 94043, or equivalent 173 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 174 (Popup - Footnote) * Pierce #13075 or equivalent 175 (Popup - Footnote) † Pierce #12722 or equivalent 176 (Popup - Footnote) ‡ Varian #96-000099-00 or equivalent 177 (Popup - Footnote) § Hamilton 702N or equivalent 178 (Popup - Footnote) i Gas chromatographic methods are extremely sensitive to the materials used Mention of trade names by Standard Methods does not preclude the use of other existing or as-yet-undeveloped products that give demonstrably equivalent results 179 (Popup - Footnote) # Durawax-DX3, 0.25-µm film, or equivalent 180 (Popup - Footnote) ** DB-1, 0.25-µm film, or equivalent 181 (Popup - Footnote) †† Burdick and Jackson #216 or equivalent 182 (Popup - Footnote) ‡‡ Such as that available from Aldrich Chemical Company 183 (Popup - Footnote) §§ Such as that available from AMVAC Chemical Corporation, Los Angeles, CA 184 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 185 (Popup - Footnote) * Chromatographic methods are extremely sensitive to the materials used Mention of trade names by Standard Methods does not preclude the use of other existing or as-yet-undeveloped © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater products that give demonstrably equivalent results 186 (Popup - Footnote) † J&W Scientific 187 (Popup - Footnote) † J&W Scientific 188 (Popup - Footnote) ‡ Supelco 189 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1994 190 (Popup - Footnote) * Wheaton: Industrial Glassware, Millville, NJ; or equivalent 191 (Popup - Footnote) † Kontes or equivalent 192 (Popup - Footnote) ‡ Eberbach or equivalent 193 (Popup - Footnote) § Durabond-1701, J&W Scientific, or equivalent 194 (Popup - Footnote) i Durabond-5, J&W Scientific, or equivalent 195 (Popup - Footnote) # Durabond-210, J&W Scientific, or equivalent 196 (Popup - Footnote) ** Aldrich or equivalent 197 (Popup - Footnote) †† Paxton Woods Glass, Cincinnati, OH, or equivalent 198 (Popup - Footnote) ‡‡ Omnisolv, manufactured by EM Science, Gibbstown, NJ, or equivalent 199 (Popup - Footnote) §§ Aldrich or equivalent 200 (Popup - Footnote) i i Carbitol (Aldrich), or equivalent 201 (Popup - Footnote) ## Diazald (Aldrich), or equivalent 202 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1994 203 (Popup - Footnote) † This reagent is known under various synonyms The more common are o-(2,3,4,5,6-pentafluorophenyl)methylhydroxylamine hydrochloride with CAS RN 57981-02-9 and pentafluorobenzyloxylamine hydrochloride (PFBOA) It also has appeared with the acronym PFBHOX 204 (Popup - Footnote) © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater * I-Chem Research, Hayward, CA, or equivalent 205 (Popup - Footnote) † Eberbach Corp., or equivalent 206 (Popup - Footnote) ‡ Durabond-5, J&W Scientific, or equivalent 207 (Popup - Footnote) § Durabond-1701, J&W Scientific, or equivalent 208 (Popup - Footnote) i Burdick & Jackson, Muskegon, MI, or equivalent 209 (Popup - Footnote) # Sigma Chemical Co., St Louis, MO, or equivalent 210 (Popup - Footnote) ** Milli-Q, Millipore Corp., Bedford, MA, or equivalent 211 (Popup - Footnote) †† Hydrion, Micro Essential Lab., Inc., Brooklyn, NY 212 (Popup - Footnote) ‡‡ Aldrich Chemical Co., or equivalent 213 (Popup - Footnote) ĐĐ Parafilmđ, American Can Co., Greenwich, CT, or equivalent 214 (Popup - Footnote) i i Aldrich Chemical Company, Inc., Milwaukee, WI, or equivalent 215 (Popup - Footnote) i i Aldrich Chemical Company, Inc., Milwaukee, WI, or equivalent 216 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 217 (Popup - Footnote) * Base/neutral extractables: acenaphthene, acenaphthylene, anthracene, aldrin, benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, benzo(ghi)perylene, benzyl butyl phthalate, β-BHC, δ-BHC, bis(2-chloroethyl) ether, bis(2-chloroethoxy) methane, bis(2-ethylhexyl) phthalate, bis(2-chloroisopropyl) ether more correctly known as 2,2-oxybis (1-chloropropane), 4-bromophenyl phenyl ether, chlordane, 2-chloronaphthalene, 4-chlorophenyl phenyl ether, chrysene, 4,4′-DDD, 4,4′-DDE, 4,4′-DDT, dibenzo(a,h)anthracene, di-n-butylphthalate, 1,3-dichlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 3,3′-dichlorobenzidine, dieldrin, diethyl phthalate, dimethyl phthalate, 2,4-dinitrotoluene, 2,6-dinitrotoluene, di-n-octylphthalate, endosulfan sulfate, endrin aldehyde, fluoranthene, fluorene, heptachlor, heptchlor epoxide, hexachlorobenzene, hexachlorobutadiene, hexachloroethane, indeno(1,2,3-cd)pyrene, isophorone, naphthalene, nitrobenzene, N-nitrosodi-n-propylamine, PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, PCB-1260, phenanthrene, pyrene, toxaphene, 1,2,4-trichlorobenzene Acid extractables: 4-chloro-3-methylphenol, 2-chlorophenol, 2,4-dichlorophenol, 2,4-dimethylphenol, © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater 2,4-dinitrophenol, 2-methyl-4,6-dinitrophenol, 2-nitrophenol, 4-nitrophenol, pentachlorophenol, phenol, 2,4,6-trichlorophenol The method may be extended to include the following compounds: benzidine, α-BHC, γ-BHC, endosulfan I, endosulfan II, endrin, hexachlorocyclopentadiene, N-nitrosodimethylamine, N-nitrosodiphenylamine 218 (Popup - Footnote) † Kontes K-570050-1025 or equivalent 219 (Popup - Footnote) ‡ Kontes K-570001-0500 or equivalent 220 (Popup - Footnote) § Kontes K-503000-0121 or equivalent 221 (Popup - Footnote) i Kontes K-569001-0219 or equivalent 222 (Popup - Footnote) # Hershberg-Wolf Extractor, Ace Glass Co., Vineland, NJ, P/N 6841-10, or equivalent 223 (Popup - Footnote) ** Gas chromatographic methods are extremely sensitive to the materials used Mention of trade names by Standard Methods does not preclude the use of other existing or as-yet-undeveloped products that give demonstrably equivalent results 224 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 225 (Popup - Footnote) * 4-Chloro-3-methylphenol, 2-chlorophenol, 2,4-dichlorophenol, 2,4-dimethylphenol, 2,4-dinitrophenol, 2-methyl-4,6-dinitrophenol, 2-nitrophenol, 4-nitrophenol, pentachlorophenol, phenol, 2,4,6-trichlorophenol 226 (Popup - Footnote) † Gas chromatographic methods are extremely sensitive to the materials used Mention of trade names by Standard Methods does not preclude the use of other existing or as-yet-undeveloped products that give demonstrably equivalent results 227 (Popup - Footnote) ‡ Davison grade 923 or equivalent 228 (Popup - Footnote) § For U.S federal permit-related analyses, use samples obtainable from U.S EPA Environmental Monitoring and Support Laboratory, Cincinnati, OH 229 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 230 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 231 (Popup - Footnote) © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater * Acenaphthene, acenaphthylene, anthracene, benzo-(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(ghi)perylene, benzo(k)fluoranthene, chrysene, dibenzo(a,h)anthracene, fluoranthene, fluorene, indeno(1,2,3-cd)pyrene, naphthalene, phenanthrene, and pyrene 232 (Popup - Footnote) † Perkin Elmer No 089-0716 or equivalent 233 (Popup - Footnote) ‡ Corning 3-75 or equivalent 234 (Popup - Footnote) § Gas chromatographic methods are extremely sensitive to the materials used Mention of trade names by Standard Methods does not preclude the use of other existing or as-yet-undeveloped products that give demonstrably equivalent results 235 (Popup - Footnote) i Davison, grade 923 or equivalent 236 (Popup - Footnote) # For U.S federal permit-related analyses, use samples obtainable from U.S EPA Environmental Monitoring and Support Laboratory, Cincinnati, OH 237 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1996 238 (Popup - Footnote) * Aldicarb sulfoxide, aldicarb sulfone, oxamyl, methomyl, 3-hydroxycarbofuran, aldicarb, baygon, carbofuran, carbaryl, and methiocarb 239 (Popup - Footnote) † HPLC methods are extremely sensitive to the materials used Mention of trade names by Standard Methods does not preclude the use of other existing or as-yet-undeveloped products that give demonstrably equivalent results 240 (Popup - Footnote) ‡ Kratos URS 051 and URA 100, or equivalent 241 (Popup - Footnote) Đ Millipore Type HA, 0.45 àm, for water, and Millipore Type FH, 0.5 µm, for organics, or equivalent 242 (Popup - Footnote) Đ Millipore Type HA, 0.45 àm, for water, and Millipore Type FH, 0.5 µm, for organics, or equivalent 243 (Popup - Footnote) i Millipore stainless steel XX300/200, or equivalent 244 (Popup - Footnote) # Nuclepore 180406, 7035 Commerce Circle, Pleasanton, CA 94566–3294, or equivalent 245 (Popup - Footnote) ** Gelman Sciences Acro LC 13, 0.45-µm disposable filter assembly, or equivalent, for aqueous © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater samples 246 (Popup - Footnote) †† Millipore, Super-Q, or equivalent 247 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1993 248 (Popup - Footnote) * No Chromix, Godax, Varick Place, New York, NY, or equivalent 249 (Popup - Footnote) † Hydrox, Matheson Gas Products, P O Box E, Lyndhurst, NJ, or equivalent 250 (Popup - Footnote) ‡ Gas Chrom Q, Applied Science Labs., Inc., P O Box 440, State College, PA, or equivalent 251 (Popup - Footnote) § J & W Scientific, DB-5, DB-1701, or equivalent 252 (Popup - Footnote) i J & W Scientific, DB-1, or equivalent 253 (Popup - Footnote) # Gas chromatographic methods are extremely sensitive to the materials used Mention of trade names by Standard Methods does not preclude the use of other existing or as-yet-undeveloped products that give demonstrably equal results 254 (Popup - Footnote) ** Use E M QuantTM, MCB Manufacturing Chemists, Inc., 2909 Highland Ave., Cincinnati, OH, or equivalent 255 (Popup - Footnote) †† FlorisilTM or equivalent 256 (Popup - Footnote) ‡‡ Gas-Chrom QTM, Supelcoport, or equivalent 257 (Popup - Footnote) §§ FlorisilTM or equivalent 258 (Popup - Footnote) * FlorisilTM or equivalent 259 (Popup - Footnote) * Aldrin, α-BHC, β-BHC, δ-BHC, γ-BHC, chlordane, 4,4′-DDD, 4,4′-DDE, 4,4′-DDT, dieldrin, endosulfan I, endosulfan II, endosulfan sulfate, endrin, endrin aldehyde, heptachlor, heptachlor epoxide, toxaphene, PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, PCB-1260 260 (Popup - Footnote) ‡ Kontes K-42054 or equivalent 261 (Popup - Footnote) § Gas chromatographic methods are extremely sensitive to the materials used Mention of trade names by Standard Methods does not preclude the use of other existing or as-yet-undeveloped © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater products that give demonstrably equivalent results 262 (Popup - Footnote) i E Merck, EM Science Quant or equivalent 263 (Popup - Footnote) #Florisil or equivalent 264 (Popup - Footnote) ** For U.S federal permit-related analyses, use samples obtainable from U.S EPA Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 265 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1994 266 (Popup - Footnote) * Aldrich Chemical or equivalent 267 (Popup - Footnote) * APPROVED BY STANDARD METHODS COMMITTEE, 1996 268 (Popup - Footnote) * Aminex, BioRad Labs, A-9 cation exchange and A-27 anion exchange resins, or equivalent 269 (Popup - Footnote) † Whatman #1 or equivalent © Copyright 1999 by American Public Health Association, American Water Works Association, Water Environment Federation ... American Water Works Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater ground, and wastewaters as well as drinking water Some industrial process waters,... Association, Water Environment Federation Standard Methods for the Examination of Water and Wastewater Quality Control See Section 4020 and individual methods for quality control methods and precision and. .. Environment Federation Standard Methods for the Examination of Water and Wastewater bromination of the phenol red occur readily If the reaction is buffered to pH 4.5 to 4.7, the color of the brominated