Separation and Quantitation of Three Acidic Herbicide Residues in Tobacco and Soil by Dispersive Solid-Phase Extraction and UPLC–MS/MS

Abstract

A method for the determination of three acidic herbicides, dicamba, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) in tobacco and soil has been developed based on the use of liquid-liquid extraction and dispersive solid-phase extraction (dispersive-SPE) followed by UPLC-MS/MS. Two percentage of (v/v) formic acid in acetonitrile as the extraction helped partitioning of analytes into the acetonitrile phase. The extract was then cleaned up by dispersive-SPE using primary secondary amine as selective sorbents. Quantitative analysis was done in the multiple-reaction monitoring mode using stable isotope-labeled internal standards for each compound. A separate internal standard for each analyte is required to minimize sample matrix effects on each analyte, which can lead to poor analyte recoveries and decreases in method accuracy and precision. The total analysis time was <4 min. The linear range of the method was from 1 to 100 ng mL(-1) with a limit of detection of each herbicide varied from 0.012 to 0.126 ng g(-1). The proposed method is faster, more sensitive and selective than the traditional methods and more accurate and robust than the published LC-MS/MS methods.

Simultaneous determination of liensinine, isoliensinine and neferine in rat plasma by UPLC–MS/MS and application of the technique to pharmacokinetic studies

“…The usefulness of this technique has been demonstrated for a wide range of applications in bioanalytical, environmental, and pharmaceutical research (Agnesod et al, 2013;Vijaya Bhaskar Reddy et al, 2013;Xiong et al, 2013). Thus, in the present work a highly rugged, selective and rapid UPLC-MS/MS method has been developed and fully validated as per the USFDA guidelines for simultaneous measurement of liensinine, isoliensinine and neferine in rat plasma using carbamazepine as internal standard (IS).…”

Evaluation of a Stable Isotope-Based Direct Quantification Method for Dicamba Analysis from Air and Water Using Single-Quadrupole LC–MS

“…While performing the full scan analysis of dicamba, however, we also found the fragment m / z 175 [M-COOH] − corresponding to the same chromatographic peak of dicamba ( Figure 3 ). The m / z 175 ion is also a commonly found fragment ion of dicamba reported in several studies as the MS2 product ion within MS/MS experiments [ 12 , 13 , 17 , 40 ]. In our analysis, the intensity of m / z 175 was observed to be significantly higher than the intensity of m / z 219 ( Figure 2 ); therefore, both m / z 175 and 219 were included as monitored SIM ions in the method.…”

Chemometric-assisted QuEChERS extraction method for post-harvest pesticide determination in fruits and vegetables

“…As 2,4-D is a relatively strong acid (pKa = 3) and more stable at low pH values 35 , it is important to maintain pH control in the extraction solvent. Moreover, as the dissociated form of 2,4-D is highly polar, it is soluble in aqueous solutions and less soluble in water-immiscible organic solvents 36 , whereas carbendazim, thiabendazole, iprodione, and prochloraz are readily soluble in most organic solvents (i.e., methanol, acetonitrile, and acetone). Therefore, the addition of toluene to the extraction solvent was examined to improve the recoveries.…”