Second-order advantage with excitation-emission fluorescence spectroscopy and a flow-through optosensing device. Simultaneous determination of thiabendazole and fuberidazole in the presence of uncalibrated interferences

G. PICCIRILLI, G. ESCANDAR

ANALYST

Royal Society of Chemistry

Lugar: Londres; Año: 2010

0003-2654

<!-- /* Font Definitions */ @font-face {font-family:MTSY; panose-1:0 0 0 0 0 0 0 0 0 0; mso-font-alt:"Arial Unicode MS"; mso-font-charset:129; mso-generic-font-family:auto; mso-font-format:other; mso-font-pitch:auto; mso-font-signature:3 151388160 16 0 524289 0;} @font-face {font-family:"@MTSY"; panose-1:0 0 0 0 0 0 0 0 0 0; mso-font-charset:129; mso-generic-font-family:auto; mso-font-format:other; mso-font-pitch:auto; mso-font-signature:3 151388160 16 0 524289 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> This paper presents a novel approach for the simultaneous determination of two widely used fungicides in a very interfering environment, combining the advantage of a spectrofluorimetric optosensor coupled to a flow-injection system and the selectivity of second-order chemometric algorithms. The sensor is based on the simultaneous retention of thiabendazole and fuberidazole on a non-selective sensing support (octadecyl silane C18 gel) placed inside a quartz flow-cell. After the arrival of the analytes to the sensing zone, the flow is stopped and the excitation-emission fluorescence matrix is read in a fast-scanning spectrofluorimeter. Different second-order calibration algorithms were selected for data processing, namely parallel factor analysis (PARAFAC) and unfolded and multidimensional partial least-squares coupled to residual bilinearization (U- and N-PLS/RBL). These algorithms achieve the second-order advantage, and are in principle able to overcome the problem of the presence of unexpected interferences. The power of U-PLS/RBL to quantify both fungicides at parts-per-billion levels, even in the presence of high concentrations of spectral interferences such as carbaryl, carbendazim and 1-naphthylacetic acid, is demonstrated. Using a sample volume of 2 mL, detection limits of 4 ng mL−1 and 0.3 ng mL−1 for thiabendazole and fuberidazol were respectively obtained in samples without interferences. In samples containing interferences, the limits of detection were 17 and 1 ng mL–1 for thiabendazole and fuberidazol, respectively. The sample frequency, including excitation/emission fluorescence matrix measurements, was 12 samples h-1. The sensor was satisfactorily applied to the determination of both analytes in real water samples.