Measurement of the Trace Elements Cu, Zn, Fe, and Mg and the Ultratrace Elements Cd, Co, Mn, and Pb in Limited Quantity Human Plasma and Serum Samples by Inductively Coupled Plasma-Mass Spectrometry

Gang Li,Lance A Schell,J David Robertson,Shih-Wen Lin,John D Brockman

doi:10.4236/ajac.2012.39084

Abstract

In public health studies limited volumes of blood are often collected and stored for future hypothesis testing. Archived samples are irreplaceable and therefore it is valuable to develop analytical techniques that require minimal sample vo-lume. This work describes the measurement of trace elements Mg, Cu, Fe, Zn and ultratrace elements Cd, Co, Mn, Pb in limited quantity (150 μL) human serum or plasma samples. Samples were digested using a hotblock and analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The analytical method was evaluated using a quadrupole (Q) and sector field high resolution (SF) instrument to analyze trace elements in Seronorm? quality control serum material. The method was used to analyze 1888 blinded human plasma samples which were archived for the National Cancer Institute from the Nutrition Intervention Trial in Linxian China. The inductively coupled plasma method was capable of accurately analyzed limited quantity samples of human serum and plasma for the trace elements Mg, Cu, Fe Zn and the ultra trace elements Co, Mn and Pb. The concentration of Cd in human plasma samples was below the level of detection for 75% of the samples analyzed.

Highlights

Epidemiologists and scientists interested in studying nutritional, environmental, biologic and genetic factors that influence human health often collect and process blood samples into plasma or serum for analytical testing
This paper examines the accuracy and precision of a digestion procedure for analysis of the trace elements Cu, Zn, Fe, Mg and the ultratrace elements Cd, Co, Mn and Pb in 150 μL of serum and plasma samples
The isotope 26Mg was measured in the Q ICPMS method because 24Mg, which has a higher abundance occasionally produced count rates outside the upper limits of the sequential dynode electron multiplier detector of the (Q) inductively coupled plasma mass spectrometry (ICP-MS)

Summary

Introduction

Epidemiologists and scientists interested in studying nutritional, environmental, biologic and genetic factors that influence human health often collect and process blood samples into plasma or serum for analytical testing. Many studies that report trace element concentrations in serum and plasma samples require a minimum of 500 μL of sample [1,2,3,4,5]. In these publications, sample preparation is limited to a “dilute and shoot” procedure. The dilute and shoot methods require a nebulizer with sample flow rates of 1 mL/min or greater. This can be a challenge in small volume samples for ultra-trace elements such as Co, Pb and Cd which require a 1:10 to 1:20 sample dilution

Results

Discussion

Conclusion