Simultaneous determination of 31 elements in foodstuffs by ICP-MS after closed-vessel microwave digestion: Method validation based on the accuracy profile

• Optimisation and validation of 31 elements by ICP-MS method.
• Simultaneous analysis of both trace and major elements.
• Simultaneous analysis of interfered and non-interfered elements (with collision cell).
• Validation by accuracy profile procedure.

This article describes an optimisation and validation process for the simultaneous determination of 31 elements – lithium, boron, sodium, magnesium, aluminium, potassium, calcium, titanium, vanadium, chromium, iron, manganese, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, selenium, strontium, molybdenum, silver, cadmium, tin, antimony, tellurium, barium, mercury, lead and uranium – in food samples by inductively coupled plasma-mass spectrometry (ICP-MS) after closed-vessel microwave digestion. In order to improve the limits of quantification of certain elements for risk assessment in the context of the first French Infant Total Diet Study (iTDS), the analytical conditions of the multi-elemental method were optimised. The validation was conducted using the evaluation of several performance criteria such as linearity, specificity, precision under repeatability conditions, intermediate precision reproducibility and limits of quantification (LOQ), with the use of the accuracy profile. Furthermore, the method was supervised by several external quality controls (EQC). Results indicate that this method could be used in the laboratory for the routine determination of these 31 essential and non-essential elements in foodstuffs with acceptable analytical performance. A more sensitive method will be necessary for Hg and Pb to decrease at the lowest the percentage of left-censored data for this iTDS.