Flow Injection for Sample Introduction into Inductively Coupled Plasma for the Determination of Boron in Biological Samples

Abstract

An important aspect of any BNCT Program is the ability to rapidly and quantitatively determine boron in a variety of biological sample types. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) has proven to be well-suited for boron analysis in biological samples^(1,2). Detection limits for boron by ICP-AES are typically less than 0.010 μg boron/mL in the analytical solution (biological samples at 1 μg boron/g can be quantitated with dilution factors as large as 100) and the linear dynamic range is in the range of five to six orders of magnitude. The major limitation of boron determinations by ICP-AES is attributed to problems with carryover⁽³⁾. At the INEL BNCT laboratory, we have found that a rinse cycle utilizing both basic and acidic conditions helps to limit this problem. Unfortunately, the rinse procedure is time consuming and drives the total analysis time to 5–7 minutes per sample, depending upon the boron concentration of the previous sample. To limit the required rinse time, samples that are expected to have very high boron concentrations are diluted so the resulting analytical solution concentrations are less than 5 μg boron/mL.