Determination of borates in caviare by ion-exclusion chromatography

A specific and rapid analytical procedure for the determination of borates in caviare was developed using ion-exclusion chromatography. Products requi re minimal pre-treatment, are simply extracted with eluent and filtered pri or to chromatography. Isolation of the analyte as a 2:1 sorbitol-borate com plex was accomplished using an anion exchange column with an eluent consist ing of 2mm sorbitol, and conductivity detection was used. Among five sugar alcohols examined for complexation, sorbitol was found to provide optimum r esolution and a 3-4 times enhancement of response over borate anion alone. The response of the complex was linear over at least a 100 fold range in co ncentration (0.1-10 mu g boron/ml) with a correlation coefficient of 0.9997 . Using a boric acid standard solution, the limits of detection and quantit ation were 0.065 mu g/ml and 0.216 mu g/ml, respectively, calculated as bor on. Replicate analyses (n = 5) for samples having commercially added borate (equivalent to 300-1000 mu g/g boron) gave RSD values of 1.18-2.03%. Recov eries of borate from fortified samples having commercially added borate pre sent varied from 94.5 to 101.1% while untreated samples exhibited recoverie s of 78.5-108.0% over a concentration range of 23-1039 mu g/g, calculated a s boron.