Flame atomic absorption spectrometric determination of serum zinc: collaborative study.

Area of Science:

• Clinical Chemistry
• Analytical Chemistry
• Trace Element Analysis

Background:

• Accurate determination of serum zinc concentrations is crucial for diagnosing and managing various health conditions.
• Existing methods may lack standardization or sufficient accuracy for widespread clinical use.
• The need for a robust and reproducible assay for serum zinc is well-established in laboratory medicine.

Purpose of the Study:

• To collaboratively study and validate a new method for determining serum zinc concentrations.
• To assess the method's accuracy, precision, and reliability across multiple laboratories.
• To establish a standardized protocol for routine serum zinc analysis.

Main Methods:

• Serum samples were analyzed in polypropylene tubes.
• Direct dilution of samples with 0.03% Brij 35.
• Zinc determination using flame atomic absorption spectrophotometry (AAS) with certified standard reference material for external control.

Main Results:

• The method demonstrated good repeatability with relative standard deviations (RSDr) of 1.2% and 11.4% at different concentration levels.
• Reproducibility relative standard deviations (RSDR) were 6.1% and 12.9% for serum zinc concentrations of 6.36 and 0.63 µg/mL, respectively.
• The method achieved interim official first action approval by AOAC, indicating its reliability.

Conclusions:

• The validated flame atomic absorption spectrophotometry (AAS) method provides accurate and reproducible measurements of serum zinc.
• This method is suitable for routine clinical laboratory use.
• The AOAC interim approval signifies the method's readiness for official adoption.