Determination of Trace Elements in Whole Blood by ICP-MS with Simple Dilution of Samples

Importance of the Topic

Trace elements play critical roles in human metabolism as components of enzymes, hormones, and biomarkers of nutritional and toxicological status. Whole blood analysis is particularly informative but traditionally requires complex sample preparation prone to contamination and analyte loss. A streamlined, sensitive approach for multi‐element determination can enhance throughput and reliability in clinical, forensic, and research laboratories.

Goals and Study Overview

This study aims to establish a rapid, accurate, and simple method for quantifying 19 trace and major elements in whole blood using direct dilution and inductively coupled plasma mass spectrometry (ICP‐MS). By avoiding extensive digestion or extraction steps, the protocol seeks to reduce labor, minimize contamination, and support high sample throughput.

Methodology and Instrumentation

Whole blood samples were diluted 20-fold with a matrix of 0.2% nitric acid containing 0.1 mg/L gold as a stabilizer. Calibration standards covering 19 elements (As, Ba, Cd, Cr, Li, Mn, Ni, Pb, Sb, Sn, Sr, Tl, Se, Cu, Ca, Mg, Fe, Hg, Zn) were prepared in the same diluent. An internal standard mixture (Be, Sc, Ge at 1000 µg/L; In, Y, Bi at 500 µg/L) in 10% isopropanol/0.2% HNO₃ was added online at a 9:1 ratio. Instrumental measurements were performed on a Shimadzu ICPMS-2050 with a DC04 nebulizer, cyclone spray chamber, mini‐torch, nickel skimmer cone, and AS-20 autosampler. Operating conditions included 1.20 kW RF power; plasma, auxiliary, and carrier gas flows of 9.0, 1.10, and 0.85 L/min; collision/reaction gases He and H₂; and a sampling depth of 6 mm.

Main Results and Discussion

Method detection limits (MDLs) ranged from 0.03 µg/L for Sb to 110 µg/L for Ca (mg/L unit for Ca and Fe), with most analytes below 1 µg/L. Precision tests at 1 µg/L spike level yielded relative standard deviations below 3% for all elements. Spike recovery studies in bovine whole blood demonstrated recoveries between 90.3% and 110%, confirming method accuracy. Long‐term stability over four hours showed signal ratios within ±5% for Fe, Hg, and Se under both He and H₂ collision modes.

Benefits and Practical Applications

The direct‐dilution ICP-MS approach eliminates complex digestion, reducing contamination risk and saving time and labor. Low sample consumption enables large‐scale screening in clinical diagnostics, nutritional monitoring, toxicology, and QA/QC in pharmaceutical and environmental laboratories. The availability of H₂ collision gas enhances Se sensitivity, while He mode maintains robust interference removal.

Used Instrumentation

• Shimadzu ICPMS-2050 system
• DC04 nebulizer
• Cyclone spray chamber
• Mini-torch and nickel skimmer cone
• AS-20 autosampler with online internal standard kit

Future Trends and Possibilities

Advances may include fully automated online dilution and sample introduction systems, further reduction of detection limits by novel collision/reaction gases, and adaptation to other biological matrices such as serum or urine. Integration with high‐throughput robotics and data analytics could facilitate large‐scale population studies and point‐of‐care testing. Emerging portable ICP-MS platforms may extend field applications in environmental and forensic investigations.

Conclusion

The presented direct‐dilution ICPMS-2050 method offers a fast, accurate, and low‐contamination solution for multi‐element determination in whole blood. It demonstrates excellent sensitivity, precision, recovery, and stability, making it well suited for diverse analytical laboratories.

Reference

No specific literature references were provided within the original document.