High-order calibration for the spectrofluorimetric determination of pesticides based on photochemical derivatization. A solution of the problems of inner-filter effects and matrix interferences in complex environmental water

• Emission-excitation-irradiation time-volume fourth-order data array was measured.
• An alternating fitting weighted residue quadrilinear decomposition algorithm was developed.
• It is based on the incompletely unfolded matrices along two different modes.
• It has been further extended to address the matrix effect from environmental water.
• Quantifying pesticides with no or weak native fluorescence was realized.

The paper reports a simple and effective spectrofluorimetric method for the quantitative analysis of the pesticide with no or weak fluorescence in complex environmental water using photochemical derivatization and high-order calibration. Through constructing four objective functions according to the pseudo-fully unfolded matrices of quadrilinear model along two different modes, a new third-order calibration algorithm named as alternating fitting weighted residue quadrilinear decomposition (AFWRQLD) has been proposed with excellent performance. Most importantly, since the matrix effect from environmental water induces partial fluorescence quenching of the fluorescent photochemical derivative of imidacloprid, AFWRQLD has been further extended for the analysis of fourth-order emission–excitation–UV irradiation time–volume data array. Satisfactory results has been obtained for the quantitative analysis of artificial river samples spiked with imidacloprid by extracting the extra mode to extract the relationship between the target analyte and the volume of environmental water. The spectral and UV irradiation time profiles yielded by the methodology are in good agreement with experimental observations. The average recovery is 93.9 ± 5.2% with a root-mean-square error of prediction of 7.4 ng mL− 1 and the detection limit of 16.0 ng mL− 1. Due to inner-filter effects and matrix interferences widely existing in increasingly severe aquatic environment, the strategy can be expected to open a new avenue for further insight into the health of aquatic ecosystem.