scholarly journals Optimization of a Multiresidue Analysis of 65 Pesticides in Surface Water Using Solid-Phase Extraction by LC-MS/MS

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6627
Author(s):  
Bahar Nakhjavan ◽  
Jason Bland ◽  
Maryam Khosravifard

An analytical method was developed and validated for simultaneous quantitation of 65 pesticides, including one single solid-phase extraction (SPE) procedure in surface water by liquid chromatography coupled to tandem mass spectroscopy. Different parameters that have an influence on extraction efficiency were evaluated in this research. Different types of cartridges, elution solvents, and sorbent drying time were investigated, and the most appropriate one was selected. Moreover, various pretreatment techniques were applied to remove sediments from water without the loss of pesticides. Centrifugation was introduced as the best option at the beginning of sample preparation to resolve the clogging of the sorbent cartridges. The recoveries of all pesticides ranged from 70% to 120%, with a relative standard deviation of less than 13.7%. The feasibility of the method was evaluated on 10 surface water samples with different concentrations of sand, sediment, and particles.

Author(s):  
Kamran Bashir ◽  
Zhimin Luo ◽  
Guoning Chen ◽  
Hua Shu ◽  
Xia Cui ◽  
...  

Griseofulvin (GSF) is clinically employed to treat fungal infections in humans and animals. GSF was detected in surface waters as a pharmaceutical pollutant. GSF detection as an anthropogenic pollutant is considered as a possible source of drug resistance and risk factor in ecosystem. To address this concern, a new extraction and enrichment method was developed. GSF-surface molecularly imprinted polymers (GSF-SMIPs) were prepared and applied as solid phase extraction (SPE) sorbent. A dispersive solid phase extraction (DSPE) method was designed and combined with HPLC for the analysis of GSF in surface water samples. The performance of GSF-SMIPs was assessed for its potential to remove GSF from water samples. The factors affecting the removal efficiency such as sample pH and ionic strength were investigated and optimized. The DSPE conditions such as the amount of GSF-SMIPs, the extraction time, the type and volume of desorption solvents were also optimized. The established method is linear over the range of 0.1–100 µg/mL. The limits of detection and quantification were 0.01 and 0.03 µg/mL respectively. Good recoveries (91.6–98.8%) were achieved after DSPE. The intra-day and inter-day relative standard deviations were 0.8 and 4.3% respectively. The SMIPs demonstrated good removal efficiency (91.6%) as compared to powder activated carbon (67.7%). Moreover, the SMIPs can be reused 10 times for water samples. This is an additional advantage over single-use activated carbon and other commercial sorbents. This study provides a specific and sensitive method for the selective extraction and detection of GSF in surface water samples.


Author(s):  
Zhen Li ◽  
Hongwei Sun

The reliable quantification of perfluoroalkyl carboxylic acids (PFCAs) in environmental samples like surface water by using gas chromatography (GC) remains challenging because the polar PFCAs call for derivatization before injection and problems involving the integration of sample pretreatment and derivatization procedures. Here we proposed a cost-effective method for the GC based determination of C4–C12 PFCAs in surface water samples by integrating solid phase extraction and PFCAs anilide derivatization. First, we assessed the performance of different PFCAs derivatization methods, namely esterification and amidation. Esterification was unable to derivatize C4–C6 PFCAs. On the contrary, amidation procedures by using 2,4-difluoroaniline (DFA) and N,N′-dicyclohexylcarbodiimide (DCC) could successfully transform all the PFCA analogs to produce anilide derivatives, which could be easily detected by GC. Then the reaction conditions in the amidation approach were further optimized by using orthogonal design experiments. After optimizing the instrumental parameters of GC, the limits of detection (LOD) of this derivatization method were determined to be 1.14–6.32 μg L−1. Finally, in order to establish an intact method for the quantification of PFCAs in surface water samples, solid phase extraction (SPE) was used for extraction and cleanup, which was further integrated with the subsequent amidation process. The SPE-amidation-GC method was validated for application, with good accuracy and precision reflected by the PFCAs recoveries and derivatization of triplicates. The method reported here could provide a promising and cost-effective alternative for the simultaneous determination of C4–C12 PFCAs in environmental water samples.


2000 ◽  
Vol 83 (6) ◽  
pp. 1327-1333 ◽  
Author(s):  
Thomas C Mueller ◽  
Scott A Senseman ◽  
R Don Wauchope ◽  
Chris Clegg ◽  
Roddy W Young ◽  
...  

Abstract An interlaboratory comparison was conducted in 1997 and 1998 to examine the feasibility of using C18 solid-phase extraction disks (Empore™) to simultaneously determine the herbicides atrazine, bromacil, and metolachlor and the insecticide chlorpyrifos in water samples. A common fortification source and sample processing procedure were used to minimize variation in initial concentrations and operator inconsistencies. The protocol consisted of paired laboratories in different locations coordinating their activities and shipping fortified water samples (deionized or local surface water) or Empore disks on which the pesticides had been retained and then quantitating the analytes by a variety of gas chromatographic methods. Average recoveries from all laboratories were >80% for atrazine, bromacil, and metolachlor, and >70% for chlorpyrifos. Detection of bromacil was unachievable at some locations because of chromatographic problems. Shipping samples between cooperating laboratories did not affect the recovery of atrazine, chlorpyrifos, or metolachlor in either matrix. Recoveries tended to be higher from disks shipped to cooperating laboratories compared with those from fortified water. Shipping disks eliminated many problems associated with the shipment of water samples, such as bottle breakage, higher shipping cost, and possible pesticide degradation. Recoveries of bromacil and metolachlor were lower from fortified surface water samples than from fortified deionized water samples. This collaborative research demonstrated that pesticides in water samples can be concentrated on solid-phase extraction disks at one location and quantitated under diverse analytical conditions at another location. The extraction efficiencies of the disks were comparable with or better than the recoveries obtained from the shipped water samples, and the problems associated with shipping water samples were eliminated by using the disks.


2018 ◽  
Vol 90 (11) ◽  
pp. 6827-6834 ◽  
Author(s):  
Pierpaolo Tomai ◽  
Andrea Martinelli ◽  
Stefano Morosetti ◽  
Roberta Curini ◽  
Salvatore Fanali ◽  
...  

2020 ◽  
Vol 16 (4) ◽  
pp. 436-446
Author(s):  
Vallerie A. Muckoya ◽  
Philiswa N. Nomngongo ◽  
Jane C. Ngila

Background: Parabens are synthetic esters used extensively as preservatives and/or bactericides in personal care personal products. Objective: Development and validation of a novel robust chemometric assisted analytical technique with superior analytical performances for the determination of ethylparaben, methylparaben and propylparaben, using simulated wastewater matrix. Methods: An automated Solid Phase Extraction (SPE) method coupled with liquid chromatographymass spectrometry was applied in this study. A gradient elution programme comprising of 0.1% formic acid in deionised water (A) and 0.1% formic acid in Methanol (B) was employed on a 100 x 2.1 mm, 3.0 μm a particle size biphenyl column. Two-level (2k) full factorial design coupled with response surface methodology was used for optimisation and investigation of SPE experimental variables that had the most significant outcome of the analytical response. Results: According to the analysis of variance (ANOVA), sample pH and eluent volume were statistically the most significant parameters. The method developed was validated for accuracy, precision, Limits of Detection (LOD) and Limit of Quantification (LOQ) and linearity. The LOD and LOQ established under those optimised conditions varied between 0.04-0.12 μgL−1 and 0.14-0.40 μgL−1 respectively. The use of matrix-matched external calibration provided extraction recoveries between 78-128% with relative standard deviations at 2-11% for two spike levels (10 and 100 μgL-1) in three different water matrices (simulated wastewater, influent and effluent water). Conclusion: The newly developed method was applied successfully to the analyses of parabens in wastewater samples at different sampling points of a wastewater treatment plant, revealing concentrations of up to 3 μgL−1.


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