1、Designation: D 3082 09Standard Test Method forBoron in Water1This standard is issued under the fixed designation D 3082; 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 t
2、he 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. Th
3、erange 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 wa
4、ter 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
5、 other 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-bili
6、ty of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D 1066 Practice for Sampling SteamD 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on Water
7、D 3370 Practices for Sampling Water from Closed ConduitsD 4841 Practice for Estimation of Holding Time for WaterSamples Containing Organic and Inorganic ConstituentsD 5810 Guide for Spiking into Aqueous SamplesD 5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Wa
8、ter AnalysisE60 Practice for Analysis of Metals, Ores, and RelatedMaterials by Molecular Absorption SpectrometryE 275 Practice for Describing and Measuring Performanceof Ultraviolet and Visible Spectrophotometers3. Terminology3.1 Definitions: For definitions of terms used in this testmethod, refer t
9、o Terminology D 1129.4. 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 formed. This colored product is taken up inisopropyl alcohol and is rea
10、d 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 todetermine its concentration in potable, natural, and wastewa-ters. Thi
11、s test method provides a means of determining theboron concentration of these waters. The holding time for thesamples may be calculated in accordance with Practice D 4841.5.2 Boric acid is used for chemical shim control of neutronflux in a nuclear reactor. This test method serves to determineif the
12、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 of thehardness salts in isopropyl alcohol. The turbidity can beelimi
13、nated by filtering the final solution through a 0.45-mmembrane filter before reading on the spectrophotometer.6.2 Organic color may be present in the sample that couldaffect absorbance readings on the spectrophotometer. If aninterfering organic color is present in the sample, the following1This test
14、 method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.05 on Inorganic Constituentsin Water.Current edition approved May 15, 2009. Published May 2009. Originallyapproved in 1972. Last previous edition approved in 2003 as D 3082 03.2This t
15、est method is similar to, but not identical with that appearing in StandardMethods for Examination 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 se
16、rviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, U
17、nited States.procedure 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) and add 3 drops in excess. Evaporate todryness on a steam or hot-water bath. If desired, o
18、rganicmaterial 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 the contents into a calibratedcentrifuge tube, wash the platinum dish with 3 or 4 mL ofw
19、ater, 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 bechecked. Porcelain or ceramic-type dishes may contain boron-fluxingagents.7. Apparatus7.1 All
20、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 540nm. The photometric practices prescribed in this test methodshall conform to Practice E60
21、. Spectrophotometers shallconform to Practice E 275. Measure absorbance using a 50-mmcell.7.4 Evaporating Dishes, 100 to 150 mL capacity.8. Reagents8.1 Reagent grade chemicals shall be used in all tests.Unless otherwise indicated, all reagents shall conform to thespecifications of the Committee on A
22、nalytical Reagents 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 otherw
23、ise indicated, referencesto water shall be understood to mean reagent water conformingto Specification D 1193, 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
24、 reagent water chosen 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 H3B
25、O3in water and dilute to 1 L. Store thesolution in a plastic bottle or boron-free container. Alterna-tively, certified boron stock solutions are commercially avail-able through chemical supply vendors and may be used.NOTE 3If boric acid is heated, it gradually loses water, changing firstto metaboric
26、 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. Store in
27、 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 methods
28、 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.9. Sampling9.1 C
29、ollect the samples in accordance with Practice D 1066or Practices D 3370.9.2 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-resistant, boron-free glass. No other preserva-tion is require
30、d.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.10.2 Develop the color complex as directed in 11.1 through11.4. Me
31、asure the absorbance of each standard at 540 nm in a50-mm cell using a reagent blank as the reference solution toset zero absorbance on the spectrophotometer. Plot absorbanceversus concentration on linear graph paper. The calibrationcurve is linear from 0.1 to 1.0 mg/L.11. Procedure11.1 Pipet 1.0 mL
32、 of a clear, filtered sample 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
33、to mix contents.11.2 Place 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.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washi
34、ngton, 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 Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.5The sole
35、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 will receivecareful consideration at a meeting of the responsible technical committee,1whic
36、hyou may attend.D308209211.3 Add 10 mL of isopropyl alcohol to each dish and stirwith a plastic rod to ensure complete dissolution of thered-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
37、 mix thoroughly.11.4 If the solution appears turbid, filter through a 0.45-mmembrane filter before reading the absorbance. Measure theabsorbance 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
38、by thecalibration curve.12. Calculation12.1 Calculations are not required, as the boron concentra-tion can be read directly from the calibration curve provided nodilution or concentration of the original sample was made.13. Precision and Bias613.1 The overall and single-operator precision of this te
39、stmethod for five laboratories varied with the concentration ofboron being measured in accordance with Fig. 1 and Fig. 2.Test method evaluation 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
40、 precision for reagent water varies lin-early with the concentration of boron being measured, and itmay be expressed mathematically as follows:St5 0.030 X 1 0.020where:St= overall precision, mg/L andX = concentration of B, mg/L.13.2 Recoveries of known amounts of boron (from boricacid) in a series o
41、f prepared standards for the five participatinglaboratories were as given in Table 1.13.3 Waters of choice arbitrarily selected by participatinground-robin laboratories consisted of natural and wastewaters.It is the users responsibility to ensure the validity of this testmethod for waters of unteste
42、d matrices.13.4 Precision and bias for this test method conforms toPractice D 2777 77, which was in place at the time ofcollaborative testing. Under the allowances made in 1.4 ofPractice D 2777 06, these precision and bias data do meetexisting requirements for interlaboratory studies of CommitteeD19
43、 test methods.14. Quality Control14.1 In order to be certain that analytical values obtainedusing these test methods are valid and accurate within theconfidence limits of the test, the following QC procedures mustbe followed when analyzing boron.6Supporting data have been filed at ASTM International
44、 Headquarters and maybe obtained by requesting Research Report RR: D19-1126.FIG. 1 Interlaboratory Precision for Boron in Reagent Water by Curcumin Colorimetric MethodD308209314.2 Calibration and Calibration Verification:14.2.1 Analyze at least three working standards containingconcentrations of bor
45、on that bracket the expected sampleconcentration, prior to analysis of samples, to calibrate theinstrument. The calibration correlation coefficient shall beequal to or greater than 0.990. In addition to the initialcalibration blank, a calibration blank shall be analyzed at theend of the batch run to
46、 ensure contamination was not a problemduring the batch analysis.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 should fall within 615 % of the known concentration.1
47、4.2.3 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 has been a major change in the measurement system, forexample, new analyst, new instrument, etc., a precision an
48、dbias study must be performed to demonstrate laboratorycapability.14.3.2 Analyze seven replicates of a standard solutionprepared from an Independent Reference Material containing amid-range concentration of boron. The matrix and chemistry ofthe solution should be equivalent to the solution used in t
49、hecollaborative study. Each replicate must be taken through thecomplete analytical test method including any sample preser-vation and pretreatment steps.14.3.3 Calculate the mean and standard deviation of theseven values and compare to the acceptable ranges of bias inTable 1. This study should be repeated until the recoveries areFIG. 2 Interlaboratory Precision for Boron in Natural Water and Waste Water (Combined Data) by Curcumin Colorimetric MethodTABLE 1 Recovery and Precision DataAmountAddedmg/LAmountFoundmg/LRecovery, % Bias, %StatisticalSignificance(95
