1、Designation: E1753 18aE1753 19Standard Practice forUse of Qualitative Chemical Spot Test Kits for Detection ofLead in Dry Paint Films1This standard is issued under the fixed designation E1753; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the use of commercial spot test kits based on either sulfide or rhodizonate
3、 for the qualitativedetermination of the presence of lead in dry paint films.1.2 This practice may also be used as a qualitative procedure for other dry coating films such as varnishes.1.3 This practice provides a list of the advantages and limitations of chemical spot test kits based on sulfide and
4、 rhodizonateto allow the user to choose the appropriate spot test for a given circumstance.1.4 This practice contains notes which are explanatory and not part of mandatory requirements.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is th
5、e responsibilityof the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability ofregulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardiz
6、ationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E1605 Terminology Relating to Lead in Buildings3. Ter
7、minology3.1 For definitions of terms relating to this practice that do not appear here, refer to Terminology E1605.3.2 Definitions of Terms Specific to This Standard:3.2.1 core samplea fragment of the entire dry paint film removed from the substrate with a coring tool which is designed toremove a sp
8、ecified area (for example, a square centimetre) of dry paint film.3.2.2 negative screena spot test for which a negative result indicates a low probability of lead being present in the testspecimen above a predetermined level; for example, a regulated federal or state abatement action level.3.2.3 neg
9、ative testthe absence of the characteristic color change within a specified time limit, usually within a few minutes.3.2.4 paint chip samplea fragment of a dry paint film removed from the substrate.3.2.5 positive testthe observation of the characteristic color change within a specified time limit, u
10、sually within a few minutes,although specific procedures for some test kits include observing the characteristic color change after an overnight waiting period.3.2.6 rhodizonate spot test methodfor lead detection, the use of a dilute solution of rhodizonate ion to test a painted surfaceor paint chip
11、 for the qualitative presence of lead (1).33.2.6.1 Discussion1 This practice is under the jurisdiction of ASTM Committee E06 on Performance of Buildings and is the direct responsibility of Subcommittee E06.23 on Lead HazardsAssociated with Buildings.Current edition approved Oct. 1, 2018Jan. 1, 2019.
12、 Published November 2018February 2019. Originally approved in 1995. Last previous edition approved in 2018 asE175318.18a. DOI: 10.1520/E175318A.10.1520/E175319.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of
13、ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The boldface numbers in parentheses refer to a list of references at the end of this practice.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an ind
14、ication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be
15、considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1A characteristic color change of the reagent from yellow/orange to pink or red indicates the presence of lead above the level ofdetection of the test kit
16、.3.2.7 sulfide spot test methodfor lead detection, the use of a dilute solution of sulfide ion to test a painted surface or paint chipfor the qualitative presence of lead (2).3.2.7.1 DiscussionA characteristic color change of the reagent from colorless to grey or black indicates the presence of lead
17、 above the level ofdetection of the spot test.4. Summary of Practice4.1 A dry paint film sample (a painted surface, paint chip, ground paint powder, or core sample) is tested for lead qualitativelythrough the use of a spot test. Spot tests kits are based on the reaction of Lead II (Pb2+) ion with ei
18、ther sulfide ion (S2) orrhodizonate ion C6O62, resulting in the characteristic color change (See 3.2.6 and 3.2.7).4.1.1 Prior to performing the spot test, the dry paint film surface is first cleaned. Except for surface tests, the film is thenprepared by either cutting a notch or an angular cut in si
19、tu or by removing a paint chip or core sample.4.1.2 The test is performed by applying the spot test reagents (directly or with the use of an adsorbent applicator) to the prepareddry paint sample and observing the characteristic color change after a specified time, usually within a few minutes.4.1.3
20、An interpretation of the presence or absence of lead in the dry paint sample is made based on the observation of thepresence or absence of the characteristic color change.5. Significance and Use5.1 This technique is applicable to dry paint films and varnishes in a variety of forms including the inta
21、ct dry paint film surface,a notched or other angular cut surface that exposes a cross section of all paint layers, a paint chip, and ground paint film.5.2 The response of the spot test method varies depending on the extractability of lead from a coating matrix, which may differdepending on the test
22、kit used, the coating type tested, and the type of lead pigment (3).5.3 In some situations, metals and other chemical species interfere with the spot tests causing false negative or false positiveresults (see Section 8).5.4 A spot test result may be used as a negative screen for the presence of lead
23、 in paints and varnishes provided the responseof the test kit is sensitive to detecting lead reliably at a given predetermined level, for example, a federal or state regulatedabatement action level (4).5.5 This practice may be used in conjunction with quantitative analytical methods for lead such as
24、 portable X-ray fluorescence,anodic stripping voltammetry, or fixed-site laboratory analysis of paint chip samples.5.6 Colorblind individuals (protanomalous viewers) who are deficient in viewing red colors may have difficulty in discerningthe pink or red color of a positive rhodizonate test.6. Appar
25、atus and Materials6.1 For Sulfide Spot Tests:6.1.1 Sulfide Based Spot Test Kit (usually consists of a 5 to 8 % solution of sodium sulfide in a dropper bottle).6.1.2 Disposable Plastic or Latex Gloves.6.2 For Rhodizonate Spot Tests:6.2.1 Rhodizonate Based Spot Test Kit (usually consists of rhodizonat
26、e reagent and an extraction solution).6.2.2 Absorbent Applicators, for applying spot test reagents or for extracting and collecting the lead from the painted surface.Absorbent applicators (that is, swabs, filter paper) may or may not be provided with a purchased test kit.6.3 For Both Sulfide and Rho
27、dizonate 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.Acceptable cuttingtools include a clean cutting knife with a fine, sharp edge, razor knife, thin s
28、calpel blade, or coring tool.6.3.4 Mortar and Pestle, for grinding paint chip sample, if necessary.6.3.5 Magnifying Glass (at least 4 power).6.3.6 Flashlight, to examine color change under incandescent light in dimly lit areas.E1753 1927. Reagents7.1 Reagents as Provided by the Spot Test KitReagents
29、 and materials kept beyond the preparers expiration date orrecommended shelf life shall be discarded. Store spot test kits at room temperature away from direct sunlight or room light. Freshlyprepared rhodizonate reagents require storage in a refrigerator to retard the rate of hydrolysis of the rhodi
30、zonate dye.7.2 Dispose of reagents according to applicable regulations promulgated by authorities having jurisdiction.8. Advantages and Disadvantages of Different Chemical Spot Tests8.1 Sulfide TestA clear solution of sodium sulfide reacts with lead in situ or on paint chips to produce a grey or bla
31、ck color(lead sulfide, PbS).8.1.1 Sulfide Test Advantages:8.1.1.1 Sulfide-based tests are rapid, easy, and relatively inexpensive to use.8.1.1.2 Sodium sulfide reacts with most lead containing pigments in paint, including lead chromate pigments within 1 or 2 min.8.1.2 Sulfide Test Disadvantages:8.1.
32、2.1 Sulfide solutions emit a toxic, potentially hazardous gas (H2S) which has an unpleasant odor (rotten eggs). Thegeneration of hazardous levels of H2S in the field, however, can be minimized by good ventilation, by using low concentrationsof sodium sulfide (not to exceed 5 to 8 %), by restricting
33、the volume of sodium sulfide solution used per test to a drop, and bycarrying only small amounts of sodium sulfide solutions (30 mL (30 mL or less). Also, since acid conditions increase the releaseof H2S gas, do not use a strong acid or an acidic solution to clean the test location either before or
34、after the sulfide test is performed.The user is cautioned to minimize breathing in the H2S fumes. In addition, since sulfide solutions are alkaline, it is recommendedthat the user consider wearing gloves and eye protection. Sulfide solutions are poisonous and are to be kept out of the reach ofchildr
35、en.8.1.2.2 Sulfide based tests are not specific for lead. In addition to lead, sulfide ion reacts with several other metal ions to givea black color including iron, nickel, cobalt, copper, mercury, and molybdenum (1, 5). Except for iron, the concentration of thesemetals in paint is usually less than
36、 1 %, which is too low to be detected by a 5 to 8 % solution of sodium sulfide (2). Iron-containingpigments, oxides, and iron blue are found in paints. Oxides are used primarily in exterior paints to provide deep earth-toned colors.Although sodium sulfide solution does not cause a color change with
37、all iron oxide pigments, positive sulfide spot test results ondeep earth-toned or blue colored paints are to be considered suspect. In these cases, the use of other test procedures for lead isrecommended.8.1.2.3 Testing paint directly on metal surfaces composed of iron, copper, or nickel (for exampl
38、e, pipes and radiators) isdiscouraged as it may lead to false positive results. An immediate dark color is formed on the surface of some treated steels, forexample, phosphate treatment.8.1.2.4 Metals other than lead and iron found in large quantities in paint include zinc, titanium, and barium, but
39、none of thesemetals produces a black color with sulfide (2). Zinc sulfides are colorless; titanium sulfides can be red or even grey, and bariumsulfides are yellow/green (1). However, these sulfides are rarely observed when testing paint with sodium sulfide spot tests becauseof the low solubility of
40、the metal species in the sodium sulfide solution.8.1.2.5 Sulfide can react with some non-lead containing paints used today to produce a grey color; however, most non-leadcontaining paints do not react with the 5 to 8 % solutions of sodium sulfide to give a grey color.8.1.2.6 It is difficult to disce
41、rn a black color against dark paints such as black, brown, dark green, or dark blue. For dark paintsother than black, the use of a magnifying glass, white tissue, or commercial cotton swab to take up the black color may aid in thedetermination of the test result. Results observed at the test locatio
42、n shall be compared to a similarly prepared control test locationprepared a few centimetres away from the test location and wetted with water. If there is no difference in appearance between thecontrol test location and the test location, the test result is considered negative.Alternatively, for bla
43、ck paint and other dark coloredpaints, the use of a rhodizonate based test kit that uses absorbent applicators or other acceptable procedures is recommended.8.1.2.7 Once exposed to air, 5 to 8 % solutions of sodium sulfide have a limited shelf life. Do not use sodium sulfide solutionsbeyond their ex
44、piration date.NOTE 1Shelf life depends upon storage, temperature, light conditions, and other use factors.8.1.2.8 If a sulfide spot test that is first conducted on a notch cut into the test surface yields a negative results, re-conduct thetest on a chip removed from the surface. Research has indicat
45、ed that some sulfide test kits have increased sensitivity when usedon a chip removed from the surface than on a notch cut into the surface (4).8.2 Rhodizonate TestA yellow/orange solution of rhodizonate reacts with lead to produce a pink or red complex (PbC6O6)under acid conditions.8.2.1 Rhodizonate
46、 Test Advantages:8.2.1.1 Rhodizonate is more specific for lead in paint than sulfide. 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 neutral or basic, the characteristic color change
47、for lead is from yellow/orange to blue or violet.However, under neutral or basic conditions, a blue or violet color change is not specific for lead (1, 6).E1753 1938.2.1.2 Rhodizonate based tests are rapid, easy, and relatively inexpensive to use.8.2.2 Rhodizonate Disadvantages:8.2.2.1 Rhodizonate b
48、ased spot tests shall not be used on red or pink paint that rubs off or bleeds color. However, rhodizonatebased spot tests that use absorbent applicators to apply the test reagents may be used on red or pink paint that does not bleed color.NOTE 3It may be determined if red or pink paint does bleed b
49、y dipping a cotton swab into the leaching solution supplied by the test kit or, if noneis provided, dipping a cotton swab into household vinegar and rubbing the cotton swab over the surface of the red or pink paint. If a red or pink coloris observed on the cotton swab, rhodizonate based tests should not be used to test these painted surfaces. Instead, it is recommended that a sodium sulfidespot test or other acceptable test method be used to determine the presence of lead.8.2.2.2 Rhodizonate ion will react with barium ion to form an orange color. Barium su
