Vanadium isotopic composition of the sea squirt ( Ciona savignyi ).

Vanadium (V) in the sea squirt (Ciona savignyi) from Onagawa Bay, Miyagi, Japan, was isolated and purified through adsorption on a diamine resin and anion and cation exchanges after the dissolution of sea squirt samples with nitric acid and hydrogen peroxide. The 50V/51V isotope ratio of V thus obtained was mass-spectrometrically determined to be from 2.51×10−3 to 2.55×10−3 with the average of 2.53×10−3 by the thermal ionisation technique. This value agreed with those of vanadyl chloride and vanadyl nitrate both prepared from vanadyl sulphate (Wako Pure Chemical Industries, Ltd., Japan) and of V in coastal seawater (Shimokita Peninsula, Aomori, Japan) within experimental uncertainties (standard deviation of±0.04), which suggested that no appreciable V isotope fractionation occurs accompanying V uptake by the sea squirt from sea water. [ABSTRACT FROM AUTHOR]