1、Designation: E2927 161Standard Test Method forDetermination of Trace Elements in Soda-Lime GlassSamples Using Laser Ablation Inductively Coupled PlasmaMass Spectrometry for Forensic Comparisons1This standard is issued under the fixed designation E2927; the number immediately following the designatio
2、n indicates the year oforiginal adoption or, in the case of 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.1NOTEEditorial corrections were made to 11.1 in
3、December 2017.INTRODUCTIONOne objective of a forensic glass examination is to compare glass samples to determine if they maybe discriminated using their physical, optical or chemical properties (for example, color, refractiveindex (RI), density, elemental composition). If the samples are distinguish
4、able in any of theseobserved and measured properties, it may be concluded that they did not originate from the samesource of broken glass. If the samples are indistinguishable in all of these observed and measuredproperties, the possibility that they originated from the same source of glass may not
5、be eliminated.The use of an elemental analysis method such as laser ablation inductively coupled plasma massspectrometry yields high discrimination among sources of glass.1. Scope1.1 This test method covers a procedure for the quantitativeelemental analysis of the following seventeen elements:lithiu
6、m (Li), magnesium (Mg), aluminum (Al), potassium (K),calcium (Ca), iron (Fe), titanium (Ti), manganese (Mn),rubidium (Rb), strontium (Sr), zirconium (Zr), barium (Ba),lanthanum (La), cerium (Ce), neodymium (Nd), hafnium (Hf)and lead (Pb) through the use of Laser Ablation InductivelyCoupled Plasma Ma
7、ss Spectrometry (LA-ICP-MS) for theforensic comparison of glass fragments. The potential of theseelements to provide the best discrimination among differentsources of soda-lime glasses has been published elsewhere(1-5).2Silicon (Si) is also monitored for use as a normalizationstandard. Additional el
8、ements may be added as needed, forexample, tin (Sn) can be used to monitor the orientation of floatglass fragments.1.2 The method only consumes approximately 0.4 to 2 g ofglass per replicate and is suitable for the analysis of fullthickness samples as well as irregularly shaped fragments assmall as
9、0.1 mm by 0.4 mm in dimension. The concentrationsof the elements listed above range from the low parts permillion (gg-1) to percent (%) levels in soda-lime-silicate glass,the most common type encountered in forensic cases. Thisstandard method may be applied for the quantitative analysis ofother glas
10、s types; however, some modifications in the referencestandard glasses and the element menu may be required.1.3 This standard does not replace knowledge, skill, ability,experience, education or training and should be used inconjunction with professional judgment.1.4 The values stated in SI units are
11、to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 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 a
12、nd determine the applica-bility of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom
13、-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.1This test method is under the jurisdiction ofASTM Committee E30 on ForensicSciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.Current edition approved Dec. 1, 2016. Publishe
14、d April 2017. Originallyapproved in 2013. Last previous edition approved in 2013 as E2927 13. DOI:10.1520/E2927-16E01.2The boldface numbers in parentheses refer to a list of references at the end ofthis standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA
15、19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Te
16、chnical Barriers to Trade (TBT) Committee.12. Referenced Documents2.1 ASTM Standards:3E2330 Test Method for Determination of Concentrations ofElements in Glass Samples Using Inductively CoupledPlasma Mass Spectrometry (ICP-MS) for Forensic Com-parisonsE177 Practice for Use of the Terms Precision and
17、 Bias inASTM Test MethodsC162 Terminology of Glass and Glass Products3. Terminology3.1 Definitions:3.1.1 calibration standard, nused to determine the quan-titative analysis for the analyte elements of interest in the glassmatrix. The calibration standard(s) shall have a known elemen-tal composition
18、including a known uncertainty for the reportedanalytes.3.1.2 glass, nan inorganic product of fusion that has beencooled to a rigid condition without crystallization. C1623.1.3 normalization standard, nan element that is presentin the glass matrix at elevated and relatively homogeneousconcentration t
19、hat may be used to normalize the laser ablationsignal to compensate for any variation on the ablated mass orinstrumental drift.4. Summary of Test Method4.1 The glass fragments usually do not require samplepreparation prior to the LA-ICP-MS analysis. However, theymay be washed with solvents or pre-ab
20、lated if necessary.4.2 The glass fragment is placed inside an ablation chamberand a laser beam is focused on the surface of the sample. Whenthe ablation is started, the interaction between the pulsed laserand the sample surface produces a cloud of very smallparticles, which are transported from the
21、ablation cell by acarrier gas into the ICP-MS for analysis.4.3 An ICP-MS is used to quantify the elements of interest.4.4 Quantitative analysis is accomplished using well-characterized glass standards whose major elemental compo-sition is similar to the material to be analyzed.4.5 A comparison betwe
22、en the reported elemental composi-tions of the known and recovered glass fragments may result ina decision on whether the samples are distinguishable byelemental composition or indistinguishable by elemental com-position.5. Significance and Use5.1 This test method is useful for the determination ofe
23、lemental concentrations in the microgram per gram (gg-1)topercent (%) levels in soda-lime glass samples. A standard testmethod may aid in the interchange of data between laboratoriesand in the creation and use of glass databases.5.2 The determination of elemental concentrations in glassprovides high
24、 discriminating value in the forensic comparisonof glass fragments.5.3 This test method produces minimal destruction of thesample. Microscopic craters of 50 to 100 m in diameter by 80to 150-m deep are left in the glass fragment after analysis. Themass removed per replicate is approximately 0.4 to 3.
25、1 g.5.4 Appropriate sampling techniques shall be used to ac-count for natural heterogeneity of the materials at a micro-scopic scale.5.5 The precision, accuracy, and limits of detection of themethod (for each element measured) shall be established ineach laboratory that employs the method. The measu
26、rementuncertainty of any concentration value used for a comparisonshall be recorded with the concentration.5.6 Acid digestion of glass followed by either InductivelyCoupled Plasma-Optical Emission Spectrometry (ICP-OES) orInductively Coupled Plasma-Mass Spectrometry (ICP-MS)may also be used for trac
27、e elemental analysis of glass, and offersimilar detection levels and the ability for quantitative analysis.However, these methods are destructive, and require largersample sizes and much longer sample preparation times (TestMethod E2330).5.7 Micro X-Ray Fluorescence (-XRF) uses comparablesample size
28、s to those used for LA-ICP-MS with the advantageof being non-destructive of the sample. Some of the drawbacksof -XRF are poorer sensitivity and precision, and longeranalysis time.5.8 Scanning Electron Microscopy with EDS (SEM-EDS) isalso available for elemental analysis, but it is of limited use for
29、forensic glass source discrimination due to poor detectionlimits for higher atomic number elements present in glass attrace concentration levels. However, distinguishing betweensources having similar RIs and densities is possible.6. Apparatus6.1 LA-ICP-MSA Laser Ablation system coupled to anICP-MS i
30、nstrument is employed. Since there are severalmanufacturers for both laser ablation units and ICP-MSinstruments, the instrument maker, model, configuration, andmajor operational parameters (that is, laser wavelength for thelaser and mass selective detector type for the ICP-MS) of bothinstruments sha
31、ll be noted within the analysis results. The mostcommon laser wavelengths used for glass analysis are 266 nm,213 nm, and 193 nm. Either quadrupole or magnetic sectorICP-MS instruments are suitable for this test method.6.2 Prior to the analysis on the day it is used, the ICP-MSshall be tuned accordin
32、g to the manufacturers recommenda-tions covering the mass range of the elements to be measured.The instrument shall be adjusted for maximum sensitivity, bestprecision, and to minimize oxides and doubly charged ioninterferences. The use of a glass reference material, such asNIST 612,4is recommended d
33、uring the tuning and perfor-mance check. Detector cross calibrations (pulse/analog) shall3For 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 Summ
34、ary page onthe ASTM website.4Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.E2927 1612be performed before any measurements when two detectormodes are used in the analysis.6.3 In order to prepare for data
35、 acquisition, the signals of thefollowing isotopes are monitored in the ICP-MS; lithium (7Li),magnesium (24 or 25Mg), aluminum (27Al), silicon (29Si),potassium (39K), calcium (42Ca), iron (57Fe), titanium (49Ti),manganese (55Mn), rubidium (85Rb), strontium (88Sr), zirco-nium (90Zr), tin (118Sn), bar
36、ium (137Ba), lanthanum (139La),cerium (140Ce), neodymium (146Nd), hafnium (180Hf) and lead(208Pb). This procedure may be applicable to other elementsand other isotopes (for example,206, 207Pb); however, thoseelements listed above are considered to provide the mostdiscrimination power for soda-lime g
37、lass comparisons.Alternatively, other isotopes such as56Fe may be monitoredusing ICP-MS with advanced technology to remove interfer-ences (for example, sector field ICP-MS or reaction cells).6.4 Either argon or helium may be used as a carrier gas totransport the particles from the ablation cell to t
38、he plasma. Theuse of helium carrier gas has been reported to result in fewerfractionation effects than the use of argon as a carrier (6).7. Hazards7.1 Commercial laser ablation units are enclosed type Ilasers. However, laser systems typically used for analysis ofglass generate high energy radiation
39、that may pose serious risksto eye safety if exposed to the eye. Interlocks shall not bebypassed or disconnected.7.2 The argon plasma shall not be observed directly withoutprotective eyewear. Potentially hazardous UV light may beemitted.7.3 ICP-MS instruments generate high amounts of radiof-requency
40、energy in their RF power supply and torch boxes thatis potentially hazardous if allowed to escape. Safety devicesand safety interlocks shall not be bypassed or disconnected.8. Calibration and Standardization8.1 A calibration curve using multiple glass standards orusing a single glass standard may be
41、 used for quantitation forLA-ICP-MS analysis of glass. Any calibration standard shallbe matrix-matched to the sample and well-characterized. Thecalibration standard(s) shall be traceable to an accepted stan-dard. For glass analysis there are several standards that areavailable such as the NIST Stand
42、ard Reference Materials (thatis, NIST 610, NIST 612, NIST 614) and the float glass standardglasses (FGS1, FGS2) evaluated by the European groupNITECRIME (5) and distributed by the Bundeskriminalamt,Germany.5A normalization standard, preferably silicon (29Si),shall be used to normalize the signal. Th
43、e use of a normaliza-tion standard is needed to adjust for differences in ablationyield between the ablated materials. Since silicon is present asa major component in all soda-lime glass (70 to 72 % as SiO2)(3, 7), a low abundance isotope (29Si) is commonly used as thenormalization standard for this
44、 method. If this method is usedfor the analysis of other glass types, the concentration of thenormalization standard shall be determined prior to quantita-tive analysis.8.2 In addition to the calibration standard, at least oneadditional glass standard reference material shall should bemeasured with
45、each sample set as a quality control check forthe accuracy and precision of the method. The quality controlspecifications shall be set by each laboratory.8.3 As a minimum, calibration standards are required at thebeginning and the end of the analytical sequence in order toadjust for instrument drift
46、 over time.Acceptance criteria for thecalibration shall be defined by each laboratory and shallinclude the use of calibration verification standards.9. Procedure9.1 If necessary, samples may be cleaned to remove anysurface contamination by washing or pre-ablation, or both,prior to analysis. Cleaning
47、 may include washing samples withsoap and water, with or without ultrasonication, and rinsing indeionized water, followed by rinsing in acetone, methanol, orethanol, and drying. Soaking in various concentrations of nitricacid for 30 minutes or longer, rinsing with deionized water andethanol, and dry
48、ing prior to analysis removes most surfacecontamination without affecting the measured concentrationsof elements inherent in the glass. However, the use of nitricacid may remove some surface coatings that may be present.9.2 Multiple samples and standards may be placed togetherin the ablation cell as
49、 long as their positions are documented.9.3 The samples or standards, or both, shall be secured inthe ablation cell using double-sided tape or other adhesive.Orient the sample to avoid an original surface of the glass. Theknown and questioned samples shall be treated equally. Thefollowing steps shall be followed:9.3.1 Purge the ablation cell with the carrier gas betweensamples to avoid any contamination.9.3.2 If pre-ablation cleaning is performed it may be done atthis point.9.3.3 Focus the laser beam at the surface of the sample.Single spot (or depth profile) abla
