Determination of lead in human saliva by combined cloud point

LUCONI, MARTA; OLSINA, ROBERTO; FERNANDEZ, LILIANA; SILVA, MARÍA FERNANDA

JOURNAL OF HAZARDOUS MATERIALS.

Elsevier

Año: 2005 vol. B128 p. 240 - 246

0304-3894

A micelle-mediated phase separation without added chelating agents to preconcentrate trace levels of lead in human saliva as a prior step to its determination by capillary electrophoresis has been developed. The enrichment step is based on the cloud point extraction of lead with the non-ionic surfactant PONPE 7.5 in the absence of chelating agent. The surfactant-rich phase was diluted with acetonitrile and the resultant solution was injected directly into the CE instrument. Factors affecting the combined methodology such as surfactant-rich phase diluting agent, buffer pH and concentration, applied voltage, sample preparation and presence of additives were studied in detail. A BGE of 20mM imidazole containing 30% acetonitrile, pH 6.20 was found to be optimal for the separation of lead from other saliva constituents. Indirect detection was performed at 205 nm. The detection limit value of lead for the preconcentration of 8ml of saliva was 11.4
g l−1. The calibration graph using the preconcentration system was linear with a correlation coefficient of 0.997 at levels near the detection limits up to at least 400
g l−1. The reproducibility (R.S.D.) on the basis of migration time and peak area were better than 0.68 and 3.6%, respectively. The method was successfully applied to the determination of lead in human saliva. The method was successfully applied to the determination of lead in human saliva. calibration graph using the preconcentration system was linear with a correlation coefficient of 0.997 at levels near the detection limits up to at least 400
g l−1. The reproducibility (R.S.D.) on the basis of migration time and peak area were better than 0.68 and 3.6%, respectively. The method was successfully applied to the determination of lead in human saliva. The method was successfully applied to the determination of lead in human saliva.
g l−1. The calibration graph using the preconcentration system was linear with a correlation coefficient of 0.997 at levels near the detection limits up to at least 400
g l−1. The reproducibility (R.S.D.) on the basis of migration time and peak area were better than 0.68 and 3.6%, respectively. The method was successfully applied to the determination of lead in human saliva. The method was successfully applied to the determination of lead in human saliva.
g l−1. The reproducibility (R.S.D.) on the basis of migration time and peak area were better than 0.68 and 3.6%, respectively. The method was successfully applied to the determination of lead in human saliva.