Accurate standardization and normalization of hepatic metal contents in Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)

Background: LA-ICP-MS is a powerful methodology for the precise determination and quantification of metals in nearly any kind of sample [1]. We recently used this method to quantify metals in experimental models and clinical samples of Wilson's disease [2 – 3]. However, measured ion intensities of selected mass-to-charge (m/z) ratios, may vary considerably from measurement to measurement and underlie non-linear drift during time. Beside proper calibration, normalization strategies for measured traces of a specific ion to a well-characterized reference material are required. Other strategies use an endogenous reference element that ideally should have a homogenous distribution within the measured sample. However, normalization methods depend on the chosen experimental setup, the sample material analyzed, and are most often based on one or few isotopes or the total ion current.