Automation of sample preparation workflow for trace elements testing by ICP-MS/MS

Objectives Inductively coupled plasma–mass spectrometry (ICP-MS) is a gold standard for testing trace elements. Despite its wide adoption in clinical laboratories, sample preparation workflows are typically manual and prone to environmental contamination. The objective of this study was to develop an automated sample preparation procedure for quantitation of zinc (Zn), copper (Cu) and selenium (Se) in serum by ICP-MS/MS. Methods Revvity Janus G3 expanded liquid handling workstation was customized to: (1) scan barcodes on specimen collection (primary) tubes and sample preparation (secondary) tubes to verify sample matching; (2) add diluent containing internal standards to secondary tubes; (3) aliquot blanks, calibrators, quality controls and human serum samples from standard rack or primary tubes to secondary tubes. Zn, Cu and Se were quantified by a multiplex ICP-MS/MS method. Results The linear regression results between the automated (y) and the manual (x) sample preparation methods were y=1.04x−0.14 (R 2 =0.999, n=264), y=1.04x−0.22 (R 2 =0.998, n=264), and y=1.03x+0.00 (R 2 =0.994, n=264) for Zn, Cu and Se, respectively. A blank batch test was performed to assess the risk of environmental contamination during automated pipetting. Other validation studies including calibration preparation verification, accuracy, precision, and stability of standards, all met the acceptable performance limits. Conclusions An automated sample preparation method was developed and validated for multiplex quantitation of Zn, Cu and Se in human serum using ICP-MS/MS. Since its implementation, we have observed quality improvements and hands-on time savings.