RIBONUCLEOTIDE ELECTROLYTES FOR CAPILLARY ELECTROPHORESIS OF POLYPHOSPHATES AND POLYPHOSPHONATES WITH INDIRECT PHOTOMETRIC DETECTION

Ribonucleotide electrolytes, namely adenosine, cytidine, guanosine, and uridine monophosphates (AMP, CMP, GMP, and UMP), are investigated for capillary electrophoresis (CE) with indirect photometric detection (IPD) of polyphosphates (P-n) and polyphosphonates (RP(n)). A separation of 12 P-n and RP(n) components in about 30 min using 5 mM ribonucleotide with 2 mM diethylenetriamine as electroosmotic now suppressor with negative polarity CE is possible. Although all of the ribonucleotide monophosphates seem to provide reasonable selectivity, AMP is the best electrolyte because of its high molar absorptivity, large dynamic reserve, and favorable transfer ratio required for a,sensitive IPD. However, the quality of separation for some P-n (particularly P-3- and P-4-phosphates) can be dramatically improved by incorporating Mg2+ in the running buffer with positive polarity, Detection limits for P-n and RP(n) range from 0.84 to 11 mu M, quite comparable to those obtained with commonly used HPLC methods, The reproducibility of the migration time is between 0.5 and 1.0% RSD, One practical application is the determination of phosphates and phosphonates in soap and various brands of toothpaste. The quantitation of glyphosate and aminomethylphosphonic acid in a commmercial herbicide is performed with an average relative error of 1.6%, The developed CE method could be applied routinely for the analysis of samples having phosphorus-containing polyvalent anions.