1、Designation: D3082 15Standard Test Method forBoron in Water1This standard is issued under the fixed designation D3082; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the
2、 year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of boron inwater and wastewaters by the curcumin colorimetric-extractionmethod2in concentrations between 0.1 and 1.0 mg/L. Ther
3、ange can be extended by dilution of the sample.1.2 Only dissolved boron is determined. This test methodrequires that the water sample be filtered through a 0.45-mmembrane filter before analysis.1.3 This test method is a colorimetric method that is verysensitive to low concentrations of boron in wate
4、r and requiresa relatively small sample volume for analysis.1.4 Precision and bias were obtained on natural and waste-waters. It is the users responsibility to ensure the validity ofthis test method for waters of untested matrices.1.5 The values stated in SI units are to be regarded asstandard. No o
5、ther units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility
6、 of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D1066 Practice for Sampling SteamD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370
7、Practices for Sampling Water from Closed ConduitsD4841 Practice for Estimation of Holding Time for WaterSamples Containing Organic and Inorganic ConstituentsD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analys
8、isE60 Practice for Analysis of Metals, Ores, and RelatedMaterials by SpectrophotometryE2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision LiquidsE275 Practice for Describing and Measuring Performance ofUltraviolet and Visible Spectrophotometers3. Terminology3.1 Defin
9、itions:3.1.1 For definitions of terms used in this test method, referto Terminology D1129.4. Summary of Test Method4.1 When a water sample containing soluble boron isacidified with hydrochloric acid and evaporated to dryness inthe presence of curcumin, a red-colored complex called roso-cyanine is fo
10、rmed. This colored product is taken up inisopropyl alcohol and is read spectrophotometrically.5. Significance and Use5.1 Because boron can be both essential and deleterious toplant growth, and because ingestion of large amounts can affectthe central nervous system in humans, a method is required tod
11、etermine its concentration in potable, natural, and wastewa-ters. This test method provides a means of determining theboron concentration of these waters. The holding time for thesamples may be calculated in accordance with Practice D4841.5.2 Boric acid is used for chemical shim control of neutronfl
12、ux in a nuclear reactor. This test method serves to determineif the boron concentration is within acceptable limits.6. Interferences6.1 Nitrate concentrations above 20 mg/L begin to interfere.Hardness levels about 100 mg/L as CaCO3give high resultsbecause of the turbidity caused by the insolubility
13、of thehardness salts in isopropyl alcohol. The turbidity can beeliminated by filtering the final solution through a 0.45-mmembrane filter before reading on the spectrophotometer.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee
14、 D19.05 on Inorganic Constituentsin Water.Current edition approved Feb. 1, 2015. Published March 2015. Originallyapproved in 1972. Last previous edition approved in 2009 as D3082 09. DOI:10.1520/D3082-15.2This test method is similar to, but not identical with that appearing in StandardMethods for Ex
15、amination of Water and Wastewater, 13th Ed., American PublicHealth Association, Washington, DC, pp 6972.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standard
16、s Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.2 Organic color may be present in the sample that couldaffect absorbance rea
17、dings on the spectrophotometer. If aninterfering organic color is present in the sample, the followingprocedure has been found useful in reducing this interferencefor some matrices. Pipet an appropriate sample aliquot into aplatinum dish (Note 1). Make alkaline to litmus with NaOHsolution (20 g/L) a
18、nd add 3 drops in excess. Evaporate todryness on a steam or hot-water bath. If desired, organicmaterial may be destroyed by ignition from 500 to 550Cbefore proceeding. Allow the platinum dish to cool and acidifywith 5 mL of HCl (1 + 19). Triturate with a rubber policemanto dissolve the residue, pour
19、 the contents into a calibratedcentrifuge tube, wash the platinum dish with 3 or 4 mL ofwater, and add to the centrifuge tube. Dilute to the 10-mLmark. Centrifuge to obtain a clear solution. Perform the samesteps on a reagent blank.NOTE 1Other types of evaporating dishes may be used but must becheck
20、ed. Porcelain or ceramic-type dishes may contain boron-fluxingagents.7. Apparatus7.1 All laboratory ware used in the performance of this testmethod must either be plastic or boron-free.7.2 Hot-Water Bath, with temperature control at 55 6 2C.7.3 Spectrophotometer, suitable for use in the range of 540
21、nm. The photometric practices prescribed in this test methodshall conform to Practice E60. Spectrophotometers shall con-form to Practice E275. Measure absorbance using a 50-mmcell.7.4 Evaporating Dishes, 100 to 150 mL capacity.7.5 ThermometerAn ASTM Gravity Thermometer havinga range from 20 to +102C
22、, as specified, and conforming tothe requirements for Thermometer 12C as prescribed in Speci-fication E2251.8. Reagents and Materials8.1 Reagent grade chemicals shall be used in all tests.Unless otherwise indicated, all reagents shall conform to thespecifications of the Committee on Analytical Reage
23、nts of theAmerican Chemical Society, where such specifications areavailable.4Other grades may be used, provided it is firstascertained that the reagent is of sufficiently high purity topermit its use without lessening the accuracy of the determi-nation.8.2 Purity of WaterUnless otherwise indicated,
24、referencesto water shall be understood to mean reagent water conformingto Specification D1193, Type I, II, or III water. Type I ispreferred and more commonly used. Type II water wasspecified at the time of round robin testing of this test method.NOTE 2The user must ensure the type of reagent water c
25、hosen issufficiently free of interferences. The water should be analyzed using thetest method.8.3 Boron Solution, Stock (1.00 mL = 1.00 mg B)Dryabout 10 g of boric acid (H3BO3) crystals in a desiccatorcontaining a silica gel desiccant for 24 h (Note 2). Dissolve5.719 g of the dry H3BO3in water and d
26、ilute to 1 L. Store thesolution in a plastic bottle or boron-free container.Alternatively, certified boron stock solutions of appropriateknown purity are commercially available through chemicalsupply vendors and may be used.NOTE 3If boric acid is heated, it gradually loses water, changing firstto me
27、taboric acid (HBO2) and finally dehydrating completely to theanhydrous oxide (B2O3). It is important therefore that oven drying not beused as a method of drying boric acid.8.4 Boron Solution, Standard (1.00 mL = 0.010 mg B)Quantitatively dilute 10.0 mL of the stock boron solution to 1L with water. S
28、tore in a plastic bottle or boron-free container.8.5 Curcumin SolutionDissolve 40 mg of finely groundcurcumin5and5gofoxalic acid (H2C2O42H2O) in 80 mL ofisopropyl alcohol.Add 4.0 mL of hydrochloric acid (HCl, sp gr1.19) and make up to 100 mL with isopropyl alcohol.NOTE 4There are other colorimetric
29、methods available for borontesting which use other indicators (the Carmine Method).8.6 Hydrochloric Acid (1 + 19)Add 1 volume of hydro-chloric acid (sp gr 1.19) to 19 volumes of water.8.7 Isopropyl Alcohol.8.8 Sodium Hydroxide Solution (20 g/L)Dissolve2gofNaOH in water and dilute to 100 mL.8.9 Filte
30、r PaperPurchase suitable filter paper. Typicallythe filter papers have a pore size of 0.45-m membrane.Material such as fine-textured, acid-washed, ashless paper, orglass fiber paper are acceptable. The user must first ascertainthat the filter paper is of sufficient purity to use withoutadversely aff
31、ecting the bias and precision of the test method.9. Sampling9.1 Collect the samples in accordance with Practice D1066or Practices D3370.9.2 Filter the sample through a 0.45-m membrane filter assoon as possible after sampling.9.3 Samples should be collected and stored in polyethylenebottles or alkali
32、-resistant, boron-free glass. No other preserva-tion is required.10. Calibration and Standardization10.1 Prepare a series of standard boron solutions to coverthe range from 0 to 1.0 mg/L. Make up standards by dilutingsuitable volumes of the boron standard solution (1.00mL = 0.010 mg B) to 100 mL.4Re
33、agent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaa
34、nd National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.5The sole source of supply of curcumin known to the committee at this time isEastman No. 1179. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments w
35、ill receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.D3082 15210.2 Develop the color complex as directed in 11.1 11.4.Measure the absorbance of each standard at 540 nm in a50-mm cell using a reagent blank as the reference solution toset zero absor
36、bance on the spectrophotometer. Read directly inconcentration if this capability is provided with the instrumentor plot absorbance versus concentration on linear graph paperor using a computer. The calibration curve is linear from 0.1 to1.0 mg/L.11. Procedure11.1 Pipet 1.0 mL of a clear, filtered sa
37、mple containing 0.1to 1.0 mg/L of boron into an evaporating dish (Treatment oforganic interferences discussed in 6.2). Run a blank and at leastone standard in conjunction with the unknown sample. Add 4mL of curcumin solution to each sample and standard, andthen, gently swirl to mix contents.11.2 Pla
38、ce the evaporating dishes in a hot-water bath that iscontrolled at 55 6 2C and evaporate to dryness.Allow 15 minafter the contents appear dry before removing. Cool to roomtemperature.11.3 Add 10 mL of isopropyl alcohol to each dish and stirwith a plastic rod to ensure complete dissolution of thered-
39、colored complex. Wash the contents of each evaporatingdish into a 25-mL volumetric flask using isopropyl alcohol.Dilute to the mark using isopropyl alcohol and mix thoroughly.11.4 If the solution appears turbid, filter through a 0.45-mmembrane filter before reading the absorbance. Measure theabsorba
40、nce of each sample and standard at 540 nm on thespectrophotometer using the reagent blank to set zero absor-bance. Record the boron concentration as indicated by thecalibration curve.12. Calculation12.1 Calculations are not required, as the boron concentra-tion can be read directly from the calibrat
41、ion curve provided nodilution or concentration of the original sample was made.13. Precision and Bias613.1 The overall and single-operator precision of this testmethod for five laboratories varied with the concentration ofboron being measured in accordance with Table 1 and Table 2.Test method evalua
42、tion included a total of seven operatorsanalyzing each sample on three consecutive days, within itsrange for reagent water and water of choice.13.1.1 The overall precision for reagent water varies lin-early with the concentration of boron being measured, and itmay be expressed mathematically as foll
43、ows:St5 0.030 X10.020 (1)where:St= overall precision, mg/L andX = concentration of B, mg/L.13.2 Recoveries of known amounts of boron (from boricacid) in a series of prepared standards for the five participatinglaboratories were as given in Table 3.13.3 Waters of choice arbitrarily selected by partic
44、ipatinground-robin laboratories consisted of natural and wastewaters.It is the users responsibility to ensure the validity of this testmethod for waters of untested matrices.13.4 Precision and bias for this test method conforms toPractice D2777 77, which was in place at the time ofcollaborative test
45、ing. Under the allowances made in 1.4 ofPractice D2777 13, these precision and bias data do meetexisting requirements for interlaboratory studies of CommitteeD19 test methods.14. Quality Control14.1 In order to be certain that analytical values obtainedusing these test methods are valid and accurate
46、 within theconfidence limits of the test, the following QC procedures mustbe followed when analyzing boron.14.2 Calibration and Calibration Verification:14.2.1 Analyze at least three working standards containingconcentrations of boron that bracket the expected sampleconcentration, prior to analysis
47、of samples, to calibrate theinstrument. The calibration correlation coefficient shall beequal to or greater than 0.990.14.2.2 Verify instrument calibration after standardization byanalyzing a standard at the concentration of one of thecalibration standards. The concentration of a mid-range stan-dard
48、 should fall within 615 % of the known concentration.Analyze a calibration blank to verify system cleanliness.14.2.3 If calibration cannot be verified, recalibrate theinstrument.14.3 Initial Demonstration of Laboratory Capability:14.3.1 If a laboratory has not performed the test before, or ifthere h
49、as been a major change in the measurement system, forexample, new analyst, new instrument, etc., a precision andbias study must be performed to demonstrate laboratorycapability.6Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D19-1126. ContactASTM CustomerService at serviceastm.org.TABLE 1 Interlaboratory Precision for Boron in Reagent Water byCurcumin Colorimetric MethodAmount Added,mg/LAmountFound, mg/LSt, mg/L So, mg/LStatisticallySignificant 95% Level1.000 0.993 0.049 0.042 ye
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