| | QC STANDARD 19: AS, BE, CA, CD, CO, CR, CU, FE, MG, MN, MO, NI, PB, SB, SE, TI, TL, V, ZN @ 100 ?G/M CRES-QC-019.5 500ml QC STANDARD 20 (SECOND SOURCE): AG, AL, AS, BA, BE, CD, CO, CR, CU, MN, MO, NI, PB, SB, SE, TH, TL, CRES-CC5608R.1 100ml QC STANDARD 21 (PRIMARY): AS, BE, CA, CD, CO, CR, CU, FE, LI, MG, MN, MO, NI, PB, SB, SE, SR, TI, TL CRES-QC-021.1 100ml |