ICP_Operations_Guide_2016

2

Quality Issues

There are several quality issues that are important with respect to multi-element chemical standards:

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Many of the topics above have been discussed in other publications on our site. Please use the links provided throughout this article to gain a better understanding of the issues discussed below. Accuracy The accuracy of a certified reference material (CRM) standard is dependent upon: t ćF NFUIPE T VTFE GPS DFSUJĕDBUJPO .FUIPE 7BMJEBUJPO * t 1SPQFS QSFQBSBUJPO PG UIF FMFNFOUBM TUBOEBSE B 2$ TBNQMF PS TFDPOE TPVSDF TBNQMF TIPVME CF BOBMZ[FE BHBJOTU UIF TJOHMF or multi-element blend). t *EFOUJĕDBUJPO BOE FYQSFTTJPO PG BMM 3BOEPN BOE 'JYFE &SSPST 4FF 6OEFSTUBOEJOH &SSPS #VEHFUT * GPS EFĕOJUJPOT (Note that uncertainty calculations will be discussed in part 3 of this series). t $IFNJDBM BOE QIZTJDBM TUBCJMJUZ ‰ $POUBJOFS 5SBOTQJSBUJPO * QMBZT BO JNQPSUBOU SPMF JO DIFNJDBM TUBCJMJUZ 4FF 4UBCJMJUZ PG t "CTFODF PG CMVOEFST USBJOJOH XSJUUFO QSPDFEVSFT EFUBJMFE SFDPSET JOUFSOBM BVEJUT FUD )BWJOH B HPPE RVBMJUZ TZTUFN in place helps to prevent laboratory blunders. See ISO Guide 34, 17025, and 9001 Explained* to learn more about out which International Organization of Standardization (ISO) standards are most important for trace analyses. Purity Purity becomes an issue when using starting materials of single element blends to prepare multi-element blends. The degree of importance increases as the relative order of magnitude of the components increases. Known purity and hopefully very clean materials are critical in the execution of ICP-OES spectral interference studies. These studies typically involve the aspiration of a 1000 μg/mL solution of a single element while collecting the spectral regions of analytes that may be interfered with. Inorganic Ventures’ laboratory has purchased many materials claiming a purity of 5 to 6-9’s. However, it’s never a bad idea to confirm a manufacturer’s claims. For more information regarding purity considerations, please consult the following online articles: Elements at ppb Concentration Levels* for detailed information on physical stability. t 1BDLBHJOH BOE TUPSBHF ‰ $POUBJOFS .BUFSJBM * 1SPQFSUJFT BSF JNQPSUBOU UP DPOTJEFS

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It’s important for the multi-element blends to be compatible with the containers in which they are prepared and stored. It’s equally important that they are compatible with the introduction system of the instrument(s) used to analyze the blend and with the other analytes within the blend. Some points to consider: t *T UIF NBUSJY PG UIF TUBOEBSE DPNQBUJCMF XJUI HMBTT PS RVBSU[ (MBTT JT OPU DPNQBUJCMF XJUI )' BOE DBVTUJD NBUSJDFT t "SF UIFSF QPTTJCMF SFBDUJPOT CFUXFFO UIF DIFNJDBM DPNQPOFOUT PG UIF TUBOEBSE UIBU NBZ BEWFSTFMZ BMUFS UIF TUBOEBSE XJUI UJNF 1IPUP SFEVDUJPO PG "H JO IJHI )$M NBUSJDFT QQU PG "H JO USBDF $M NBUSJDFT QQU PG 1C BOE #B XJUI USBDF MFWFMT PG TVMGBUF or chromate, ppt of the alkaline and rare earths with F- in HF matrices, ppt of fluorinated elements like Sn(F)x-y in the presence of elements that would complex with the fluoride and therefore ‘pull it away’ from the metal stabilized as the fluoride complex, etc.

* Visit inorganicventures.com/tech/icp-operations/ for additional information from this link