IMPROVED PEROXYOXALATE CHEMILUMINESCENCE-BASED DETERMINATIONS BY USE OF CONTINUOUS REAGENT ADDITION TO REMOVE BACKGROUND EMISSION

The continuous addition of reagent technique was used as an effective means for suppressing background emission in peroxyoxalate chemiluminescence reactions. For this purpose, the bis(2,4,6-trichlorophenyl) oxalate/hydrogen peroxide system and phenothiazine derivatives such as acepromazine, propiopromazine, thioridazine, promazine, trimeprazine, methotrimeprazine, and chlorpromazine were chosen. The influence of environmental factors such as pH, water content, reagent concentration, and addition rate on the maximum reaction rate was assessed in terms of background emission. The resulting method provides a linear response to phenothiazine derivatives over a range of 3 orders of magnitude with relative standard deviation of similar to 1-3.7% and detection limits in the picomole range far some phenothiazine derivatives, in addition to a high selectivity. The proposed method for acepromazine and propiopromazine exhibits the best analytical features and compares favorably with existing alternatives in terms of sensitivity, precision, and sampling frequency. The determination of acepromazine in horse plasma was selected to validate the proposed method for analysis of real samples.