1、Designation:E175304E175313 Standard Practice for Use of Qualitative Chemical Spot Test Kits for Detection of Lead in Dry Paint Films 1 This standard is issued under the xed designation E1753; the number immediately following the designation indicates the year of original adoption or, in the case of
2、revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval. 1. Scope 1.1 This practice covers the use of commercial spot test kits based on either sulde or rhodizonate f
3、or the qualitative determination of the presence of lead in dry paint lms. 1.2 This practice may also be used as a qualitative procedure for other dry coating lms such as varnishes. 1.3 This practice provides a list of the advantages and limitations of chemical spot test kits based on sulde and rhod
4、izonate to 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 the
5、responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents 2.1 ASTM Standards: 2 E1605Terminology Relating to Lead in Buildings E1828Practice for Evaluating the Perfo
6、rmance Characteristics of Qualitative Chemical Spot Test Kits for Lead in Paint (Withdrawn 2010) 3 3. Terminology 3.1 For denitions of terms relating to this practice that do not appear here, refer to Terminology E1605. 3.2 Denitions of Terms Specic to This Standard: 3.2.1 core samplea fragment of t
7、he entire dry paint lm removed from the substrate with a coring tool which is designed to remove a specied area (for example, a square centimetre) of dry paint lm. 3.2.2 negative screena spot test for which a negative result indicates a low probability of lead being present in the test specimen abov
8、e a predetermined level; for example, a regulated federal or state abatement action level. 3.2.3 negative testthe absence of the characteristic color change within a specied time limit, usually within a few minutes. 3.2.4 paint chip samplea fragment of a dry paint lm removed from the substrate. 3.2.
9、5 positivetesttheobservationofthecharacteristiccolorchangewithinaspeciedtimelimit,usuallywithinafewminutes, althoughspecicproceduresforsometestkitsincludeobservingthecharacteristiccolorchangeafteranovernightwaitingperiod. 3.2.6 rhodizonate spot test methodfor lead detection, the use of a dilute solu
10、tion of rhodizonate ion to test a painted surface or paint chip for the qualitative presence of lead (1). 3 Acharacteristic color change of the reagent from yellow/orange to pink or red indicates the presence of lead above the level of detection of the test kit. 1 This practice is under the jurisdic
11、tion ofASTM Committee E06 on Performance of Buildings and is the direct responsibility of Subcommittee E06.23 on Lead Hazards Associated with Buildings. Current edition approved Dec. 1, 2004Jan. 1, 2013. Published December 2004February 2013. Originally approved in 1995. Last previous edition approve
12、d in 20012004 as E175301.E175304. DOI: 10.1520/E1753-04.10.1520/E1753-13. 2 ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatserviceastm.org.ForAnnualBookofASTMStandards volume information, refer to the standards Document Summary page on the ASTM website. 3 T
13、he last approved version of this historical standard is referenced on www.astm.org. 3 The boldface numbers in parentheses refer to a list of references at the end of this practice. This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what
14、changes have been made to the previous version. Because it 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 version of the standard as published by ASTM is to be considered the
15、official document. Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States 13.2.6.1 Discussion A characteristic color change of the reagent from yellow/orange to pink or red indicates the presence of lead above the level of detection of the t
16、est kit. 3.2.7 suldespottestmethodforleaddetection,theuseofadilutesolutionofsuldeiontotestapaintedsurfaceorpaintchip for the qualitative presence of lead (2).Acharacteristic color change of the reagent from colorless to grey or black indicates the presence of lead above the level of detection of the
17、 spot test. 3.2.7.1 Discussion A characteristic color change of the reagent from colorless to grey or black indicates the presence of lead above the level of detection of the spot test. 4. Summary of Practice 4.1 Adry paint lm sample (a painted surface, paint chip, ground paint powder, or core sampl
18、e) is tested for lead qualitatively through the use of a spot test. Spot tests kits are based on the reaction of Lead II (Pb 2+ ) ion with either sulde ion (S 2 ) or rhodizonate ion C 6 O 6 2 , resulting in the characteristic color change (See 3.2.6 and 3.2.7). 4.1.1 Prior to performing the spot tes
19、t, the dry paint lm surface is rst cleaned. Except for surface tests, the lm is then prepared by either cutting a notch or an angular cut in situ or by removing a paint chip or core sample. 4.1.2 Thetestisperformedbyapplyingthespottestreagents(directlyorwiththeuseofanadsorbentapplicator)totheprepare
20、d dry paint sample and observing the characteristic color change after a specied time, usually within a few minutes. 4.1.3 An interpretation of the presence or absence of lead in the dry paint sample is made based on the observation of the presence or absence of the characteristic color change. 5. S
21、ignicance and Use 5.1 Thistechniqueisapplicabletodrypaintlmsandvarnishesinavarietyofformsincludingtheintactdrypaintlmsurface, a notched or other angular cut surface that exposes a cross section of all paint layers, a paint chip, and ground paint lm. 5.2 Theresponseofthespottestmethodvariesdependingo
22、ntheextractabilityofleadfromacoatingmatrix,whichmaydiffer 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 species interfere with the spot tests causing false negative or false positive results (see Section 8
23、). 5.4 Aspot test result may be used as a negative screen for the presence of lead in paints and varnishes provided the response of the test kit is sensitive to detecting lead reliably at a given predetermined level, for example, a federal or state regulated abatement action level (4). 5.5 Thispract
24、icemaybeusedinconjunctionwithquantitativeanalyticalmethodsforleadsuchasportableX-rayuorescence, anodic stripping voltammetry, or xed-site laboratory analysis of paint chip samples. 5.6 Colorblind individuals (protanomalous viewers) who are decient in viewing red colors may have difficulty in discern
25、ing the pink or red color of a positive rhodizonate test. 6. Apparatus and Materials 6.1 For Sulde Spot Tests: 6.1.1 Sulde Based Spot Test Kit (usually consists of a 5 to 8% solution of sodium sulde in a dropper bottle). 6.1.2 Disposable Plastic or Latex Gloves. 6.2 For Rhodizonate Spot Tests: 6.2.1
26、 Rhodizonate Based Spot Test Kit (usually consists of rhodizonate 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, lter paper) may or may not be
27、 provided with a purchased test kit. 6.3 For Both Sulde and Rhodizonate Spot Tests: 6.3.1 Non-Abrasive Cleaning Solution. 6.3.2 Towels, Towelette, or Sponge. 6.3.3 CuttingTool,usedtocutintothedrypaintlm.Acuttingtoolmayormaynotbeprovidedwiththekit.Acceptablecutting tools include a clean cutting knife
28、 with a ne, sharp edge, razor knife, thin scalpel 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. E175313 27. Reagents 7.1 R
29、eagents as Provided by the Spot Test KitReagents and materials kept beyond the preparers expiration date or recommendedshelflifeshallbediscarded.Storespottestkitsatroomtemperatureawayfromdirectsunlightorroomlight.Freshly prepared rhodizonate reagents require storage in a refrigerator to retard the r
30、ate of hydrolysis of the rhodizonate dye. 7.2 Dispose of reagents according to applicable regulations promulgated by authorities having jurisdiction. 8. Advantages and Disadvantages of Different Chemical Spot Tests 8.1 Sulde TestAclear solution of sodium sulde reacts with lead in situ or on paint ch
31、ips to produce a grey or black color (lead sulde, PbS). 8.1.1 Sulde Test Advantages: 8.1.1.1 Sulde-based tests are rapid, easy, and relatively inexpensive to use. 8.1.1.2 Sodiumsuldereactswithmostleadcontainingpigmentsinpaint,includingleadchromatepigmentswithin1or2min. 8.1.2 Sulde Test Disadvantages
32、: 8.1.2.1 Sulde solutions emit a toxic, potentially hazardous gas (H 2 S) which has an unpleasant odor (rotten eggs). The generation of hazardous levels of H 2 S in the eld, however, can be minimized by good ventilation, by using low concentrations of sodium sulde (not to exceed 5 to 8%), by restric
33、ting the volume of sodium sulde solution used per test to a drop, and by carrying only small amounts of sodium sulde solutions (30 mL or less).Also, since acid conditions increase the release of H 2 S gas, do not use a strong acid or an acidic solution to clean the test location either before or aft
34、er the sulde test is performed.The user is cautioned to minimize breathing in the H 2 S fumes. In addition, since sulde solutions are alkaline, it is recommended that theuserconsiderwearingglovesandeyeprotection.Suldesolutionsarepoisonousandaretobekeptoutofthereachofchildren. 8.1.2.2 Sulde based tes
35、ts are not specic for lead. In addition to lead, sulde ion reacts with several other metal ions to give a black color including iron, nickel, cobalt, copper, mercury, and molybdenum (1, 5). Except for iron, the concentration of these metalsinpaintisusuallylessthan1%,whichistoolowtobedetectedbya5to8%
36、solutionofsodiumsulde(2).Iron-containing pigments,oxides,andironbluearefoundinpaints.Oxidesareusedprimarilyinexteriorpaintstoprovidedeepearth-tonedcolors. Although sodium sulde solution does not cause a color change with all iron oxide pigments, positive sulde spot test results on deep earth-toned o
37、r blue colored paints are to be considered suspect. In these cases, the use of other test procedures for lead is recommended. 8.1.2.3 Testing paint directly on metal surfaces composed of iron, copper, or nickel (for example, pipes and radiators) is discouraged as it may lead to false positive result
38、s.An immediate dark color is formed on the surface of some treated steels, for example, phosphate treatment. 8.1.2.4 Metals other than lead and iron found in large quantities in paint include zinc, titanium, and barium, but none of these metals produces a black color with sulde (2). Zinc suldes are
39、colorless; titanium suldes can be red or even grey, and barium suldesareyellow/green(1).However,thesesuldesarerarelyobservedwhentestingpaintwithsodiumsuldespottestsbecause of the low solubility of the metal species in the sodium sulde solution. 8.1.2.5 Sulde can react with some non-lead containing p
40、aints used today to produce a grey color; however, most non-lead containing paints do not react with the 5 to 8% solutions of sodium sulde to give a grey color. 8.1.2.6 It is difficult to discern a black color against dark paints such as black, brown, dark green, or dark blue. For dark paints other
41、than black, the use of a magnifying glass, white tissue, or commercial cotton swab to take up the black color may aid in the determinationofthetestresult.Resultsobservedatthetestlocationshallbecomparedtoasimilarlypreparedcontroltestlocation prepared a few centimetres away from the test location and
42、wetted with water. If there is no difference in appearance between the controltestlocationandthetestlocation,thetestresultisconsiderednegative.Alternatively,forblackpaintandotherdarkcolored paints, the use of a rhodizonate based test kit that uses absorbent applicators or other acceptable procedures
43、 is recommended. 8.1.2.7 Once exposed to air, 5 to 8% solutions of sodium sulde have a limited shelf life. Do not use sodium sulde solutions beyond their expiration date. NOTE 1Shelf life depends upon storage, temperature, light conditions, and other use factors. 8.1.2.8 If a sulde spot test that is
44、 rst conducted on a notch cut into the test surface yields a negative results, re-conduct the test on a chip removed from the surface. Research has indicated that some sulde test kits have increased sensitivity when used on a chip removed from the surface than on a notch cut into the surface (4). 8.
45、2 Rhodizonate TestA yellow/orange solution of rhodizonate reacts with lead to produce a pink or red complex (PbC 6 O 6 ) under acid conditions. 8.2.1 Rhodizonate Test Advantages: 8.2.1.1 Rhodizonate is more specic for lead in paint than sulde. Under acid conditions, only lead reacts with the yellow/
46、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 for lead is from yellow/orange to blue or violet. However, under neutral or basic conditions, a blue or violet color change is not specic fo
47、r lead (1, 6). 8.2.1.2 Rhodizonate based tests are rapid, easy, and relatively inexpensive to use. E175313 38.2.2 Rhodizonate Disadvantages: 8.2.2.1 Rhodizonate based spot tests shall not be used on red or pink paint that rubs off or bleeds color. However, rhodizonate basedspotteststhatuseabsorbenta
48、pplicatorstoapplythetestreagentsmaybeusedonredorpinkpaintthatdoesnotbleedcolor. NOTE 3To determine if red or pink paint bleeds, dip a cotton swab into 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 over the s
49、urface of the red paint. If a red or pink color is observed on the cotton swab, rhodizonate based tests shall not be used to test these painted surfaces. Instead, the use of a sodium sulde spot test or other acceptable test method to determine the presence of lead is recommended. 8.2.2.2 Rhodizonate ion will react with barium ion to form an orange color. Barium sulfate was sometimes added to household paints as an extender, but because of the insolubility of barium sulfate, barium ion an
