Total Protein Determinations by Particle Beam/Hollow Cathode Optical Emission Spectroscopy

A novel method for quantitative total protein determinations is presented. Total protein content is determined by particle beam/hollow cathode optical emission spectroscopy (PB/HC-OES) through monitoring of carbon atomic emission. The PB/HC-OES offers such advantages as ease of operation, exclusion of labor-intensive sample pretreatment processes, rapid analysis, high sensitivity, and low detection limit. The method could also be adapted to be integrated to current microfluidics devices. Parametric optimization for sample introduction, nebulization, desolvation, and hollow cathode source conditions is performed for the analysis of aqueous bovine serum albumin solutions. Response curves of C (I) 193.0-nm emission were obtained under the optimized conditions with both 10% HCl and 100 (mu)g/mL KCl added to the sample matrix as potential carriers. The detection limit for triplicate injections of bovine serum albumin standards was found to be on the singlenanogram level with 200-(mu)L injections. The addition of KCl significantly improved the sensitivity, supporting the proposed "carrier effect" of chloride salts in the particle transport process. Results obtained here suggest a range of applications for the use of the PB/HC-OES source for total protein determinations; emphasis here is future use in assessing protein quantification in microfluidic systems.