Validation and quality control of an ICP-MS method for the quantification and discrimination of trace metals and application in paper analysis: an overview.

Questioned documents analysis includes: handwriting comparison, analysis of the ink and the printer used in the production of the documents, and the physical and chemical characterization of the cellulosic substrate (paper) of the documents. In many situations in life, for financial, social, and personal concerns, we depend on different documents. Therefore, over time, various analytical methods have been developed in order to determine their authenticity, source, and age or to differentiate various papers. In this study a quantitative analytical method for the determination of eight trace level chemical elements (Al, Ba, Fe, Mg, Mn, Pb, Sr, Zn) from document paper samples using inductively coupled plasma-mass spectrometry (ICP-MS) was validated and applied. The evaluation of the performance parameters of the method (applicability, fitness for purpose, linearity, working range, limit of detection and limit of quantification, sensitivity, accuracy, and precision) was accomplished. An overview of the validation parameters are presented and discussed in detail.