Recovery of Atrazine, Bromacil, Chlorpyrifos, and Metolachlor from Water Samples after Concentration on Solid-Phase Extraction Disks: Interlaboratory Study

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.

Interlaboratory Comparison of Extraction Efficiency of Pesticides from Surface and Laboratory Water Using Solid-Phase Extraction Disks

“…Results from a previous southern region collaborative project (S-271) showed that extraction efficiencies of the disks were comparable with or better than the recoveries obtained from shipped water samples (7). Also, many problems associated with shipping water samples, such as storage stability, bottle breakage, and high shipping charges were eliminated by using the disk as storage and shipping media (7). Further studies reported by Mersie et al (8) demonstrated the capacity of this technique for a wide range of compounds.…”

“…However, the difference was small enough that many samples would be required to detect the difference (6). Results from a previous southern region collaborative project (S-271) showed that extraction efficiencies of the disks were comparable with or better than the recoveries obtained from shipped water samples (7). Also, many problems associated with shipping water samples, such as storage stability, bottle breakage, and high shipping charges were eliminated by using the disk as storage and shipping media (7).…”

“…In our previous study, an interlaboratory comparison was conducted to examine the feasibility of using C 18 solid-phase extraction disks (Empore) to simultaneously determine the herbicides atrazine, bromacil, and metolachlor and the insecticide chlorpyrifos in water samples (7). A common fortification source and a common sample processing procedure were used to minimize variation in initial concentrations and operator inconsistencies.…”

Discovery of novel 3‐{[(5,5‐dimethyl‐4,5‐dihydroisoxazol‐3‐yl)sulfonyl]methyl}benzo[d]isoxazole analogs as promising very long chain fatty acids inhibitors

“…As an early herbicide of chloroacetamide, acetochlor occupies a large market, and metolachlor is the same as acetochlor [15–19] . Subsequently, Syngenta developed the optically active isomer S‐metolachlor [20–24] . In 2016, worldwide sales of S‐metolachlor reached $590 million, making it the largest acetamide herbicide, surpassing acetochlor.…”

“…[15][16][17][18][19] Subsequently, Syngenta developed the optically active isomer S-metolachlor. [20][21][22][23][24] In 2016, worldwide sales of S-metolachlor reached $590 million, making it the largest acetamide herbicide, surpassing acetochlor. At present, with the exposure of acetochlor and isopromethachlor potential hazards to human and the forbiddance of acetochlor in European Union, the herbicides containing the structural type of 3-sulfonylisooxazole, such as pyroxasulfone and fenoxasulfone were commercialized by Japanese companies in 2011 and 2014, respectively.…”