Development of the particle beam/hollow cathode optical emission spectroscopy system (PB/HC-OES) for biological sample analysis

Speciation via atomic spectroscopy methods is accomplished only by inference from empirical formulae. The coupling of particle beam sample introduction and hollow cathode optical emission spectroscopy (PB/HC-OES) was applied for empirical formula determinations of a group of organoselenium compounds. The carbon and hydrogen optical emission from the organoselenium compounds was monitored and the analyte element response (C (I) and H (I)) to glow discharge operation conditions was studied. Analytical response curves for integrated C and H emission intensities as a function of both single analyte concentration and the empirical formulae for the model compounds were obtained. In all cases, a variability of less than 10% RSD for triplicate injections of 200 muL samples is observed. The detection limits of 0.16 ppm of selenomethionine (0.05 ppm of elemental C) and 0.034 ppm of selenomethionine (0.0019 ppm of elemental H) were obtained over the concentration range of 0.01--1000 ppm. Within the 100 muL injections, these values equate to absolute masses of 16 ng of selenomethionine. The corresponding detection limits for the selenium content in se-(methyl)selenocysteine were determined to be 11 ng of elemental Se. The correlation of H (I)/C (I) emission intensity values to the atomic H/C values in different organoselenium compounds demonstrates that the PB/HC-OES system was capable of selenium speciation by means of the determination of empirical formulae. To further demonstrate the capability of the PB/HC-OES for biological sample analysis, total protein content was determined by particle beam/hollow cathode optical emission spectroscopy (PB/HC-OES) through monitoring of carbon atomic emission. Parametric optimization for sample introduction, nebulization, desolvation, and hollow cathode source conditions was performed for the analysis of aqueous bovine serum albumin solutions. The detection limit for triplicate injections of bovine serum albumin standards was found to be on the single-nanogram level with 200muL injections. KCl was shown to have carrier agent capability for the total protein determinations.; Subsequently, the potential of non-volatile salts as carrier agents was investigated in the determination of protein samples by PB/HC-OES. (Abstract shortened by UMI.)...