ASTM_D_8469_-_22.pdf

Designation:D846922Standard Test Method forAnalysis of Multiple Elements in Cannabis Matrices byInductively Coupled Plasma Mass Spectrometry(ICP-MS)1This standard is issued under the fixed designation D8469;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 the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method uses inductively coupled plasma massspectrometry(ICP-MS)to determine multiple trace elements incannabis and cannabis-related matrices following samplepreparation using microwave-assisted acid digestion.This testmethod is applicable to the quantification of trace levels ofelements in dried plant materials,concentrates,oils,extracts,tinctures of cannabis and cannabis-related products.Othermatrices may be added provided that the lab validates the extramatrices using Practice D8282.Details are provided on thevalidation of both the sample preparation procedure andanalytical method using certified reference materials(CRMs)and validation of the analytical method using spike recoverytesting of several cannabis based samples.1.2 This test method should be used by analysts experiencedin the use of microwave digestion and ICP-MS,matrixinterferences,and procedures for their correction or reduction,and should only be used by personnel trained in the handling,preparation,and analysis of samples for the determination oftrace elements in cannabis and cannabis products(1).2This testmethod was developed using a single quadrupole ICP-MSequipped with a collision/reaction cell(CRC)that can bepressurized with helium(He)gas for the removal of poly-atomic interferences using kinetic energy discrimination(KED).This test method can also be run using a triplequadrupole or“tandem”mass spectrometer(MS/MS)ICP-MSinstrument,which is fitted with CRC technology.The ICP-MSmethod accounts for polyatomic interferences,which are themost common spectral overlaps in ICP-MS,isobaricinterferences,and any potential doubly-charged ion interfer-ences(M2+)that may arise from the presence of rare earthelements(REEs)in the samples,as the REE2+ion interferencescan affect the accuracy of the measurement of arsenic(As)andselenium(Se)in the samples.Table 1 lists elements for whichthe test method applies along with recommended analyticalmasses,and secondary masses for some elements.The prioritytoxic elements arsenic(As),cadmium(Cd),mercury(Hg),andlead(Pb),also sometimes referred to as the“big four”toxictrace elements are listed separately because of their toxicity,asdiscussed in 5.1.1.3 Certified reference materials(CRMs)should be matrixmatched as closely as possible to the cannabis/plant matrix.In-house reference materials(RMs)are acceptable if no CRMis available and/or the in-house RM is well characterized,butCRMs are preferred.NIST 1575a Pine Needles,NRCHEMP-1,and a NIST hemp sample(NIST number notassigned yet)were analyzed to verify method bias.TheRM/CRMs should have a recovery between 80%to 120%when concentrations are above the limit of quantification(LOD)or within the concentration uncertainty(converted topercent relative uncertainty)supplied on the certificate,which-ever is greater.If acceptable values are not obtained,theanalytical solution may be reanalyzed once.If acceptability isstill not met,recalibrate and reanalyze the entire analyticalsequence and/or prepare and digest new analytical portions.1.4 Multi-laboratory Validation(MLV)This test methodwas tested by analyzing an NRC hemp CRM,a NIST hempSRM,and a NIST plant control sample(NIST 1575a PineNeedles)by four laboratories each running a single quadrupoleICP-MS.1.5 Gravimetric dilution(weight/weight),volumetric dilu-tion(volume/volume),or a combination of the two techniques(weight/volume)are acceptable methods for ICP-MS samplepreparation.1.6 UnitsThe values stated in SI units are to be regardedas the standard.No other units of measurement are included inthis standard.1.7 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for the1This test method is under the jurisdiction of ASTM Committee D37 onCannabis and is the direct responsibility of Subcommittee D37.03 on Laboratory.Current edition approved Aug.1,2022.Published October 2022.DOI:10.1520/D8469-22.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard