Application of a heated electrospray interface for on-line connection of the AAS detector with HPLC for detection of organotin and organolead compounds

摘要

A heated electrospray interface that affords high sensitivity and long-term signal stability for AAS detection of metal-containing analytes in organic or organic-water solvents after HPLC separation is described. The vitreous body of the electrospray interface is externally heated above the boiling point of the solvent and quartz furnace AAS is used for detection. Interface working conditions were optimized with a full experimental design for the detection of tin- (tetramethyl-, tetraethyl-, tetrabutyl-, and tetrapentyltin, tributyltin chloride, dibutyltin dichloride, and butyltin trichloride) and lead- (tetraethyl- and tetraphenyllead) containing compounds in the column eluate. The heated electrospray interface enables use of a wide range of flow rates-from 50 to 1000 μL min~(-1). The measurement sensitivity and detection limit achieved were compared with those obtained by use of the thermospray interface and post-column conversion of the organotin compounds to gaseous hydrides. The detection limits for the low-molecular weight species of the homologous series (2.8±0.1 ng (140±5 ng mL~(-1)) for tetramethyltin and 3.1±0.2 ng (155±10 ng mL~(-1)) for tetraethyltin) were obtained approximately one order of magnitude lower than those obtained by use of the thermospray interface. With this HPLC-ES-QFAAS system the tributyltin content of BCR reference material 477, mussel tissue, was analyzed. This system was also applied to analysis of tetraethyllead in gasoline samples.