Determination of vanadium in biological fluids using HR-ICP-MS

Abstract

A simple, fast and sensitive method is described for the determination of vanadium in biological fluids using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). Samples were diluted 20-fold in 0.3% HNO₃. Spectral interference from ³⁵Cl¹⁶O⁺, present in urine or serum matrices, was completely resolved from the vanadium major isotope of ⁵¹V⁺ at medium resolution of 4000. Quantitation of V in urine and serum was achieved by the method of additions using standards prepared in a pooled urine or serum sample. Mass offset and lock mass (⁴⁰Ar¹⁶O⁺) options were employed for more accurate and precise results. Better than 2.0% RSD was obtained with a 200 pg ml⁻¹ V spike added to a 20-fold diluted urine or serum matrix, reflecting one day stability. Vanadium concentrations in the range of <10 to 1500 pg ml⁻¹ and <10 to 760 pg ml⁻¹ were determined in the urine and serum samples, respectively. Good day-to-day precision of less than 4.0% RSD was typical for both sample matrices. Spike recoveries of 99 ± 2 and 98 ± 3% (one standard deviation, n = 3) were obtained in the urine and serum, respectively. An in-house CRM (SLRS-4: river water) was analyzed daily, yielding a V concentration of 0.337 ± 0.010 ng ml⁻¹ (one standard deviation, n = 35), in good agreement with the certified value of 0.32 ± 0.03 ng ml⁻¹. A detection limit (3 s) of 10 pg ml⁻¹ was estimated for V in reconstituted urine and serum samples.