AOAC OMA# 2011.14 (Final Action Review)-OMB

2011.14 (Oct. 2018) – MTE-03 Final Action Review FOR ERP USE ONLY DO NOT DISTRIBUTE

standard solution to compensate EIEs effects (e.g., K, Na, and Ca) in the plasma since certain food materials can contain substantial concentrations of these elements. This provides a significant source of electrons in the plasma. The presence of ionization buffer in all samples and standards will minimize the effects of varying concentrations of EIEs in the sample. The solution presented to the nebulizer contains a maximum of 5000 mg/kg cesium for high-salted food raw materials (e.g., culinary products or tastemakers) and a minimum of 500 mg/kg cesium (for main food samples); 20 mg/kg indium and 5 mg/kg strontium, yttrium, and chromium; less than half of each element concentration of the higher working standard Std6 and less than 0.5 g/kg total dissolved minerals. Power settings and nebulizer gas flow must be optimized to ensure that the Mg280.271:Mg285.213 ratio (Mermet principle of robust plasma) demonstrates robust operating conditions in accordance with the ratio established by the instrument manufacturer. At least three replicate readings of the same sample are performed, with relatively long integration times to minimize noise. ( b ) ICP wavelengths .—A number of recommended and alternative wavelengths may be used for the nine elements to be determined and internal standards (Table 2011.14K). As a minimum, select one recommended and one alternative wavelength for each element corrected by one recommended wavelength for appropriate internal standard. All responses for both recommended and alternative wavelengths for each element are corrected using only one internal standard line. The following is a list of wavelengths for each element (and its appropriate internal standard) in priority order that have been found acceptable for main foodstuffs: Wavelength (nm): Ca: 317.933 (In: 303.936); Cu: 324.754 (In: 303.936); Fe: 259.94 (Sr: 338.071); K: 766.491 (Sr: 460.733);