1、Designation: E 1753 04Standard Practice forUse of Qualitative Chemical Spot Test Kits for Detection ofLead in Dry Paint Films1This standard is issued under the fixed designation E 1753; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the use of commercial spot test kitsbased on either sulfide or rhodizonate for th
3、e qualitativedetermination of the presence of lead in dry paint films.1.2 This practice may also be used as a qualitative proce-dure for other dry coating films such as varnishes.1.3 This practice provides a list of the advantages andlimitations of chemical spot test kits based on sulfide andrhodizo
4、nate to allow the user to choose the appropriate spot testfor a given circumstance.1.4 This practice contains notes which are explanatory andnot part of mandatory requirements.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsib
5、ility 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:2E 1605 Terminology Relating to Lead in BuildingsE 1828 Guide for Evaluating the Performance Char
6、acteris-tics of Qualitative Chemical Spot Test Kits for Lead inPaint3. Terminology3.1 For definitions of terms relating to this practice that donot appear here, refer to Terminology E 1605.3.2 Definitions of Terms Specific to This Standard:3.2.1 core samplea fragment of the entire dry paint filmremo
7、ved from the substrate with a coring tool which isdesigned to remove a specified area (for example, a squarecentimetre) of dry paint film.3.2.2 negative screena spot test for which a negativeresult indicates a low probability of lead being present in thetest specimen above a predetermined level; for
8、 example, aregulated federal or state abatement action level.3.2.3 negative testthe absence of the characteristic colorchange within a specified time limit, usually within a fewminutes.3.2.4 paint chip samplea fragment of a dry paint filmremoved from the substrate.3.2.5 positive testthe observation
9、of the characteristiccolor change within a specified time limit, usually within a fewminutes, although specific procedures for some test kits includeobserving the characteristic color change after an overnightwaiting period.3.2.6 rhodizonate spot test methodfor lead detection, theuse of a dilute sol
10、ution of rhodizonate ion to test a paintedsurface or paint chip for the qualitative presence of lead (1).3Acharacteristic color change of the reagent from yellow/orangeto pink or red indicates the presence of lead above the level ofdetection of the test kit.3.2.7 sulfide spot test methodfor lead det
11、ection, the use ofa dilute solution of sulfide ion to test a painted surface or paintchip for the qualitative presence of lead (2). A characteristiccolor change of the reagent from colorless to grey or blackindicates the presence of lead above the level of detection ofthe spot test.4. Summary of Pra
12、ctice4.1 A dry paint film sample (a painted surface, paint chip,ground paint powder, or core sample) is tested for leadqualitatively through the use of a spot test. Spot tests kits arebased on the reaction of Lead II (Pb2+) ion with either sulfideion (S2) or rhodizonate ion C6O62, resulting in the c
13、harac-teristic color change (See 3.2.6 and 3.2.7).4.1.1 Prior to performing the spot test, the dry paint filmsurface is first cleaned. Except for surface tests, the film is thenprepared by either cutting a notch or an angular cut in situ orby removing a paint chip or core sample.1This practice is un
14、der the jurisdiction of ASTM Committee E06 on Perfor-mance of Buildings and is the direct responsibility of Subcommittee E06.23 on LeadHazards Associated with BuildingsCurrent edition approved Dec. 1, 2004. Published December 2004. Originallyapproved in 1995. Last previous edition approved in 2001 a
15、s E 1753 01.2For 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 standards Document Summary page onthe ASTM website.3The boldface numbers in parentheses refer to a l
16、ist of references at the end ofthis practice.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.1.2 The test is performed by applying the spot testreagents (directly or with the use of an adsorbent applicator) tothe prepared dry paint
17、 sample and observing the characteristiccolor change after a specified time, usually within a fewminutes.4.1.3 An interpretation of the presence or absence of lead inthe dry paint sample is made based on the observation of thepresence or absence of the characteristic color change.5. Significance and
18、 Use5.1 This technique is applicable to dry paint films andvarnishes in a variety of forms including the intact dry paintfilm surface, a notched or other angular cut surface thatexposes a cross section of all paint layers, a paint chip, andground paint film.5.2 The response of the spot test method v
19、aries dependingon the extractability of lead from a coating matrix, which maydiffer depending on the test kit used, the coating type tested,and the type of lead pigment (3).5.3 In some situations, metals and other chemical speciesinterfere with the spot tests causing false negative or falsepositive
20、results (see Section 8).5.4 A spot test result may be used as a negative screen forthe presence of lead in paints and varnishes provided theresponse of the test kit is sensitive to detecting lead reliably ata given predetermined level, for example, a federal or stateregulated abatement action level
21、(4).5.5 This practice may be used in conjunction with quanti-tative analytical methods for lead such as portable X-rayfluorescence, anodic stripping voltammetry, or fixed-site labo-ratory analysis of paint chip samples.5.6 Colorblind individuals (protanomalous viewers) whoare deficient in viewing re
22、d colors may have difficulty indiscerning the pink or red color of a positive rhodizonate test.6. Apparatus and Materials6.1 For Sulfide Spot Tests:6.1.1 Sulfide Based Spot Test Kit (usually consists ofa5to8 % solution of sodium sulfide in a dropper bottle).6.1.2 Disposable Plastic or Latex Gloves.6
23、.2 For Rhodizonate Spot Tests:6.2.1 Rhodizonate Based Spot Test Kit (usually consists ofrhodizonate reagent and an extraction solution).6.2.2 Absorbent Applicators, for applying spot test reagentsor for extracting and collecting the lead from the paintedsurface.Absorbent applicators (that is, swabs,
24、 filter paper) mayor may not be provided with a purchased test kit.6.3 For Both Sulfide and Rhodizonate Spot Tests:6.3.1 Non-Abrasive Cleaning Solution.6.3.2 Towels, Towelette, or Sponge.6.3.3 Cutting Tool, used to cut into the dry paint film. Acutting tool may or may not be provided with the kit.Ac
25、ceptable cutting tools include a clean cutting knife with afine, sharp edge, razor knife, thin scalpel blade, or coring tool.6.3.4 Mortar and Pestle, for grinding paint chip sample, ifnecessary.6.3.5 Magnifying Glass (at least 43 power).6.3.6 Flashlight, to examine color change under incandes-cent l
26、ight in dimly lit areas.7. Reagents7.1 Reagents as Provided by the Spot Test KitReagentsand materials kept beyond the preparers expiration date orrecommended shelf life shall be discarded. Store spot test kitsat room temperature away from direct sunlight or room light.Freshly prepared rhodizonate re
27、agents require storage in arefrigerator to retard the rate of hydrolysis of the rhodizonatedye.7.2 Dispose of reagents according to applicable regulationspromulgated by authorities having jurisdiction.8. Advantages and Disadvantages of Different ChemicalSpot Tests8.1 Sulfide TestA clear solution of
28、sodium sulfide reactswith lead in situ or on paint chips to produce a grey or blackcolor (lead sulfide, PbS).8.1.1 Sulfide Test Advantages:8.1.1.1 Sulfide-based tests are rapid, easy, and relativelyinexpensive to use.8.1.1.2 Sodium sulfide reacts with most lead containingpigments in paint, including
29、 lead chromate pigments within 1or 2 min.8.1.2 Sulfide Test Disadvantages:8.1.2.1 Sulfide solutions emit a toxic, potentially hazardousgas (H2S) which has an unpleasant odor (rotten eggs). Thegeneration of hazardous levels of H2S in the field, however, canbe minimized by good ventilation, by using l
30、ow concentrationsof sodium sulfide (not to exceed 5 to 8 %), by restricting thevolume of sodium sulfide solution used per test to a drop, andby carrying only small amounts of sodium sulfide solutions (30mL or less). Also, since acid conditions increase the release ofH2S gas, do not use a strong acid
31、 or an acidic solution to cleanthe test location either before or after the sulfide test isperformed. The user is cautioned to minimize breathing in theH2S fumes. In addition, since sulfide solutions are alkaline, itis recommended that the user consider wearing gloves and eyeprotection. Sulfide solu
32、tions are poisonous and are to be keptout of the reach of children.8.1.2.2 Sulfide based tests are not specific for lead. Inaddition to lead, sulfide ion reacts with several other metal ionsto give a black color including iron, nickel, cobalt, copper,mercury, and molybdenum (1, 5). Except for iron,
33、the concen-tration of these metals in paint is usually less than 1 %, whichis too low to be detected bya5to8%solution of sodiumsulfide (2). Iron-containing pigments, oxides, and iron blue arefound in paints. Oxides are used primarily in exterior paints toprovide deep earth-toned colors. Although sod
34、ium sulfidesolution does not cause a color change with all iron oxidepigments, positive sulfide spot test results on deep earth-tonedor blue colored paints are to be considered suspect. In thesecases, the use of other test procedures for lead is recommended.8.1.2.3 Testing paint directly on metal su
35、rfaces composed ofiron, copper, or nickel (for example, pipes and radiators) isdiscouraged as it may lead to false positive results. Animmediate dark color is formed on the surface of some treatedsteels, for example, phosphate treatment.8.1.2.4 Metals other than lead and iron found in largequantitie
36、s in paint include zinc, titanium, and barium, but noneE1753042of these metals produces a black color with sulfide (2). Zincsulfides are colorless; titanium sulfides can be red or even grey,and barium sulfides are yellow/green (1). However, thesesulfides are rarely observed when testing paint with s
37、odiumsulfide spot tests because of the low solubility of the metalspecies in the sodium sulfide solution.8.1.2.5 Sulfide can react with some non-lead containingpaints used today to produce a grey color; however, mostnon-lead containing paints do not react with the 5 to 8 %solutions of sodium sulfide
38、 to give a grey color.8.1.2.6 It is difficult to discern a black color against darkpaints such as black, brown, dark green, or dark blue. For darkpaints other than black, the use of a magnifying glass, whitetissue, or commercial cotton swab to take up the black colormay aid in the determination of t
39、he test result. Results observedat the test location shall be compared to a similarly preparedcontrol test location prepared a few centimetres away from thetest location and wetted with water. If there is no difference inappearance between the control test location and the testlocation, the test res
40、ult is considered negative. Alternatively,for black paint and other dark colored paints, the use of arhodizonate based test kit that uses absorbent applicators orother acceptable procedures is recommended.8.1.2.7 Once exposed to air, 5 to 8 % solutions of sodiumsulfide have a limited shelf life. Do
41、not use sodium sulfidesolutions beyond their expiration date.NOTE 1Shelf life depends upon storage, temperature, light condi-tions, and other use factors.8.1.2.8 If a sulfide spot test that is first conducted on a notchcut into the test surface yields a negative results, re-conduct thetest on a chip
42、 removed from the surface. Research hasindicated that some sulfide test kits have increased sensitivitywhen used on a chip removed from the surface than on a notchcut into the surface (4).8.2 Rhodizonate TestA yellow/orange solution of rhodi-zonate reacts with lead to produce a pink or red complex(P
43、bC6O6) under acid conditions.8.2.1 Rhodizonate Test Advantages:8.2.1.1 Rhodizonate is more specific for lead in paint thansulfide. Under acid conditions, only lead reacts with theyellow/orange rhodizonate solution to give a pink to red color(1, 6).NOTE 2If the pH of the rhodizonate reagent is neutra
44、l or basic, thecharacteristic color change for lead is from yellow/orange to blue orviolet. However, under neutral or basic conditions, a blue or violet colorchange is not specific for lead (1, 6).8.2.1.2 Rhodizonate based tests are rapid, easy, and rela-tively inexpensive to use.8.2.2 Rhodizonate D
45、isadvantages:8.2.2.1 Rhodizonate based spot tests shall not be used on redor pink paint that rubs off or bleeds color. However, rhodizon-ate based spot tests that use absorbent applicators to apply thetest reagents may be used on red or pink paint that does notbleed color.NOTE 3To determine if red o
46、r pink paint bleeds, dip a cotton swabinto the leaching solution supplied by the test kit or, if none is provided,dip the cotton swab into household vinegar and rub the cotton swab overthe surface of the red paint. If a red or pink color is observed on the cottonswab, rhodizonate based tests shall n
47、ot be used to test these paintedsurfaces. Instead, the use of a sodium sulfide spot test or other acceptabletest method to determine the presence of lead is recommended.8.2.2.2 Rhodizonate ion will react with barium ion to forman orange color. Barium sulfate was sometimes added tohousehold paints as
48、 an extender, but because of the insolubilityof barium sulfate, barium ion and, hence, the orange color, isonly rarely detected. However, since it is possible for a strongorange color to mask a weak pink color due to lead, it isrecommended that paints providing an orange color withrhodizonate be fur
49、ther tested with a sodium sulfide test kit orother acceptable lead detection method (for example, labora-tory analysis of a paint chip sample).8.2.2.3 Sulfates can interfere with the pink color develop-ment of lead rhodizonate and cause a false negative result.Substrate materials such as plaster, gypsum wallboard (sheetrock), some cement blocks, and some bricks may containsoluble sulfates.NOTE 4A rhodizonate test can be performed at a notched or angularcut test location on wallboard (sheet rock) or on a paint chip removed fromthe wallboard (sheet rock), etc., provid
