1、Designation: D 3082 03Standard 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 (e) 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. T
3、herange 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 w
4、ater 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 This standard does not purport to address all of thesafety con
5、cerns, 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 of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1066 Practice for Sampling Steam3D 11
6、29 Terminology Relating to Water3D 1192 Specification for Equipment for Sampling Waterand Steam in Closed Conduits3D 1193 Specification for Reagent Water3D 1293 Test Methods for pH of Water3D 2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D-19 on Water3D
7、 3370 Practices for Sampling Water from Closed Con-duits3D 4841 Practice for Estimation of Holding Time forWater Samples Containing Organic and Inorganic Con-stituents3D 5810 Guide for Spiking into Aqueous Samples3D 5847 Practice for the Writing Quality Control Specifica-tions for Standard Test Meth
8、ods for Water Analysis3E60 Practice for Photometric and SpectrophotometricMethods for Chemical Analysis of Metals4E 200 Practice for Preparation, Standardization, and Stor-age of Standard and Reagent Solutions for ChemicalAnalysis5E 275 Practice for Describing and Measuring Performanceof Ultraviolet
9、, Visible, and Near Infrared Spectrophotom-eters63. Terminology3.1 Definitions: For definitions of terms used in this testmethod, refer to 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 p
10、resence of curcumin, a red-colored complex called roso-cyanine is formed. 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
11、affectthe central nervous system in humans, a method is required todetermine 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
12、 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 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 CaCO3
13、give high resultsbecause of the turbidity caused by the insolubility of thehardness salts in isopropyl alcohol. The turbidity can be1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.05 on Inorganic Constituentsin Water.Curr
14、ent edition approved Jan. 10, 2003. Published January 2003. Originallyapproved in 1972. Last previous edition approved in 1996 as D 3082 92 (1996).2This test method is similar to, but not identical with that appearing in StandardMethods for Examination of Water and Wastewater, 13th Ed., American Pub
15、licHealth Association, Washington, DC, pp 6972.3Annual Book of ASTM Standards, Vol 11.01.4Annual Book of ASTM Standards, Vol 03.05.5Annual Book of ASTM Standards, Vol 15.05.6Annual Book of ASTM Standards, Vol 03.06.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM Int
16、ernational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.eliminated 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 th
17、e 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) and add 3 dr
18、ops in excess. Evaporate todryness on a steam or hot-water bath. If desired, organicmaterial may be destroyed by ignition at 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 con
19、tents 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 bechecked. Porc
20、elain 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 540nm. The
21、photometric practices prescribed in this test methodshall conform to Practice E60. 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
22、 indicated, all reagents shall conform to thespecifications of the Committee on Analytical Reagents of theAmerican Chemical Society, where such specifications areavailable.7Other grades may be used, provided it is firstascertained that the reagent is of sufficiently high purity topermit its use with
23、out lessening the accuracy of the determi-nation.8.2 Purity of WaterUnless otherwise 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
24、of round robin testing of this test method.NOTE 2The user must ensure the type of 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 desiccatorco
25、ntaining a silica gel desiccant for 24 h (Note 2). Dissolve5.719 g of the dry H3BO3in water and dilute to 1 L. Store thesolution in a plastic bottle or boron-free container.NOTE 3If boric acid is heated, it gradually loses water, changing firstto metaboric acid (HBO2) and finally dehydrating complet
26、ely 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 a plastic bottle or boron-free container.8.
27、5 Curcumin SolutionDissolve 40 mg of finely groundcurcumin8and5gofoxalic 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.8.6 Hydrochloric Acid (1 + 19)Add 1 volume of hydro-chloric acid (sp gr 1.19) to 19 vo
28、lumes 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 Collect the samples in accordance with Practice D 1066,Specification D 1192, or Practices D 3370.9.2 Filter the sample through a 0.45-m membrane filter assoon as p
29、ossible after sampling.9.3 Samples should be collected and stored in polyethylenebottles or alkali-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 standa
30、rds 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. Measure 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
31、 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 of a clear, filtered sample containing 0.1to 1.0 mg/L of boron into an evaporating dish (Treatment oforganic interferences discussed in 6.
32、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 Place the evaporating dishes in a hot-water bath that iscontrolled at 55 6 2C and evaporate to dryness.Allow 15 minaft
33、er 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-colored complex. Wash the contents of each evaporating7Reagent Chemicals, American Chemical Society Specifications,
34、 AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc.
35、 (USPC), Rockville,MD.8Curcumin is available through Eastman No. 1179.D3082032dish 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 absorb
36、ance. 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 by thecalibration curve.12. Calculation12.1 Calculations are not required, as the boron concentra-tion can be read di
37、rectly from the calibration curve provided nodilution or concentration of the original sample was made.13. Precision and Bias913.1 The overall and single-operator precision of this testmethod for five laboratories varied with the concentration ofboron being measured in accordance with Fig. 1 and Fig
38、. 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 precision for reagent water varies lin-early with the concentration of boron being measured, and itmay be expressed
39、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 of prepared standards for the five participatinglaboratories were as given in Table 1.13.3 Waters of choice arbitraril
40、y 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 untested matrices.13.4 Precision and bias for this test method conforms toPractice D 2777 77, which was in place at the time
41、 ofcollaborative testing. Under the allowances made in 1.4 ofPractice D 2777 98, 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
42、are valid and accurate 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 sampleconcentrati
43、on, prior to analysis of samples, to calibrate the9Supporting data have been filed at ASTM Headquarters. Request RR:D19-1126.FIG. 1 Interlaboratory Precision for Boron in Reagent Water by Curcumin Colorimetric MethodD3082033instrument. The calibration correlation coefficient shall beequal to or grea
44、ter than 0.990. In addition to the initialcalibration blank, a calibration blank shall be analyzed at theend of the batch run to ensure contamination was not a problemduring the batch analysis.14.2.2 Verify instrument calibration after standardization byanalyzing a standard at the concentration of o
45、ne of thecalibration standards. The concentration of a mid-range stan-dard should fall within 615 % of the known concentration.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 bef
46、ore, or ifthere has been a major change in the measurement system, forexample, new analyst, new instrument, etc., a precision andbias study must be performed to demonstrate laboratorycapability.14.3.2 Analyze seven replicates of a standard solutionprepared from an Independent Reference Material cont
47、aining amid-range concentration of boron. The matrix and chemistry ofthe solution should be equivalent to the solution used in thecollaborative study. Each replicate must be taken through thecomplete analytical test method including any sample preser-vation and pretreatment steps. The replicates may
48、 be inter-spersed with samples.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 arewithin the limits given in Table 1. If a concentration other thanthe recommended concentrat
49、ion is used, refer to PracticeD 5847 for information on applying the F test and t test inevaluating the acceptability of the mean and standard devia-tion.14.4 Laboratory Control Sample (LCS):14.4.1 To ensure that the test method is in control, analyzea LCS containing a known concentration of boron with eachbatch or 10 samples. If large numbers of samples are analyzedFIG. 2 Interlaboratory Precision for Boron in Natural Water and Waste Water (Combined Data) by Curcumin Colorimetric MethodTABLE 1 Recovery and Precision DataAmountAddedmg/LAmountFoundmg/LRecovery, %
