Nylon membrane as a fluorimetric probe for the herbicide bentazone

JÉSSICA P. CHIARANDINI ; GRACIELA M. ESCANDAR

ANALYTICAL AND BIOANALYTICAL CHEMISTRY

SPRINGER HEIDELBERG

Lugar: HEIDELBERG; Año: 2011 vol. 402 p. 2221 - 2225

1618-2642

The fluorimetric signal produced by the herbicide bentazone retained in selectedsolid-surfaces was investigated. Among the different tested supports, only a microporousnylon membrane demonstrated to be able to produce the desired signal. The nature of thesolvent employed for depositing bentazone on the nylon surface was found to be critical forobtaining high fluorescence intensity. A user-friendly strategy was implemented, spotting afew microliters of the analyte solution over the membrane and acquiring the fluorescencespectra directly from the solid-surface. The quantitative study was carried out by both zeroth?and second?order calibrations. Improved selectivity and sensitivity were attained with thelatter calibration mode and, therefore, it was selected for subsequent quantitative experimentsin both synthetic and real samples. The fact that BTZ contained in natural waters must beextracted in chloroform to be spotted over nylon allowed the pre-concentration of the analyte.A volume of water was percolated through a C18 membrane and the retained BTZ was theneluted with a small volume of chloroform. Following the suggested procedure, a detectionlimit of 0.4 ng mL?1 (0.003 ng/spot), a prediction relative error of 8 % and a samplefrequency of about 10 samples h?1 were obtained in spiked natural waters of different origins,highlighting the usefulness of the proposed approach.