Determination of dichlobenil and its major metabolite (BAM) in onions by PTV–GC–MS using PARAFAC2 and experimental design methodology

Abstract

The optimization of a GC-MS analytical procedure which includes derivatization, Quick Easy Cheap Effective Rugged and Safe (QuEChERS) and programmed temperature vaporization (PTV) using design of experiments is performed to determine 2,6dichlorobenzonitrile (dichlobenil) and 2,6dichlorobenzamide (BAM) in onions, using 3,5dichlorobenzonitrile and 2,4dichlorobenzamide as internal standards. The use of a central composite design and two D-optimal designs, together with the desirability function, makes it possible to significantly reduce the economic, time and environmental cost of the study. The usefulness of PARAFAC2 for solving problems as the interference of unexpected derivatization artifacts unavoidably linked to some derivatization agents, or the presence of coeluents from the complex matrix, which share m/z ratios with the target compounds, is shown. The limits of decision (CC) of the optimized procedure, 5.00 g kg -1 for dichlobenil and 1.55 g kg -1 for BAM (=0.05), are bellow the maximum residue limit (MRL) established by the EU for dichlobenil (20 g kg -1 ) in this commodity.

Modeling and Optimization of Phosphate Recovery from Industrial Wastewater and Precipitation of Solid Fertilizer using Experimental Design Methodology

“…Central composite, Dohelert and Box Behnken designs are widely used and allow the researcher to choose the most suitable one for approaching the optimization problem [13][14][15][16][17] . Struvite (MgNH 4 PO 4 · 6H 2 O) precipitation from industrial wastewater streams occurs under certain environmental conditions of pH, alkalinity, temperature, phosphorus, ammonium and magnesium concentrations which vary with water source and interfering ions presence.…”

Ad-hoc blocked design for the robustness study in the determination of dichlobenil and 2,6-dichlorobenzamide in onions by programmed temperature vaporization-gas chromatography–mass spectrometry

“…[19]. The 524 tolerance intervals obtained for the relative abundances are shown in Table 3, fourth column.…”

“…The analytical 100 procedure is explained in detail in Ref. [19], where it can be seen that it depends on several 101…”

“…It is particularly helpful for determining compounds of interest in food 114 commodities [19,24], for solving problems as small retention time shifts, severe interferences 115 caused by unexpected derivatization artifacts or by co-eluents of the complex matrix which 116 share m/z ratios with the target compounds. The second-order advantage of PARAFAC2 117 allows the determination of the target analytes in samples where unknown interferents are 118 present without the need of calibrate them.…”

“…As it has just mentioned, the experimental procedure under 130 study depends (or may depend) upon 18 experimental factors [19]. An experimental design is 131 set with the factors at two levels to perform the robustness study of the analytical procedure.…”