Partial least-squares with residual bilinearization for the spectrofluorimetric determination of pesticides. A solution of the problems of inner-filter effects and matrix interferents

Abstract

This paper demonstrates for the first time the power of a chemometric second-order algorithm for predicting, in a simple way and using spectrofluorimetric data, the concentration of analytes in the presence of both the inner-filter effect and unsuspected species. The simultaneous determination of the systemic fungicides carbendazim and thiabendazole was achieved and employed for the discussion of the scopes of the applied second-order chemometric tools: parallel factor analysis (PARAFAC) and partial least-squares with residual bilinearization (PLS/RBL). The chemometric study was performed using fluorescence excitation-emission matrices obtained after the extraction of the analytes over a C18-membrane surface. The ability of PLS/RBL to recognize and overcome the significant changes produced by thiabendazole in both the excitation and emission spectra of carbendazim is demonstrated. The high performance of the selected PLS/RBL method was established with the determination of both pesticides in artificial and real samples.

Second- and higher-order data generation and calibration: A tutorial

“…In 2006, the power of U-PLS/RBL was experimentally demonstrated for the first 505 time, by correctly predicting the concentration of two selected analytes (the fungicides 506 carbendazim and thiabendazole) through EEFMs read in a C18 membrane, in which the 507 analytes were retained, in the presence of unexpected species and overcoming the inner 508 filter effect [60]. Significant changes are produced by thiabendazole in both the 509 excitation and emission spectra of carbendazim.…”

Analytical applications of second-order calibration methods

“…The application of second-order algorithms to DAD-MS data has improved considerably the resolution and quantitation of coeluted biocide compounds in the LC analysis of complex environmental samples. PARAFAC, GRAM, TLD and PLS-RBL have been used to determine the same family of pesticides using fluorescence data [107][108][109].…”

Improvement of residual bilinearization by particle swarm optimization for achieving the second‐order advantage with unfolded partial least‐squares

“…In this report, PSO is applied after U-PLS calibration of a series of simulated and experimental data, previous to the use of RBL for achieving the second-order advantage. It should be noticed that we have data available for several experimental systems where U-PLS/RBL has shown some advantages over PARAFAC, because of the presence of deviations from tri-linearity brought about by phenomena such as: (1) linear dependency in one or both data dimensions [32,36], (2) interactions between analyte and background [29], (3) inner filter effects [31,33], (4) severe spectral overlapping [32], etc. However, in order to better appreciate the phenomenon under discussion, we have prepared a new experimental data set, where two analytes are calibrated and two potential interferents occur.…”