Poly(lauryl methacrylate-co-1,6-hexanediol ethoxylate diacrylate) modified silica-based dispersive solid-phase extraction for determination of phenylurea herbicides in environmental water samples

In this study, poly(lauryl methacrylate-co-1,6-hexanediol ethoxylate diacrylate) (LMA-HEDA) was synthesised on silanised silica through free-radical cross-linking polymerisation process. The optimal preparation process was obtained by investigating the effects of polymerisation temperature and reaction time. Characterisation of the LMA-HEDA-modified silica was achieved using diffuse reflectance FT-IR. The resulting LMA-HEDA-modified silica was then utilised as a sorbent for dispersive solid-phase extraction (dSPE) of phenylurea herbicides (PUHs) from various environmental water samples. The optimisation of LMA-HEDA-based dSPE process was achieved by investigating the effect of the following parameters including extraction time, pH of sample solution, composition of elution solvent and addition of salt on the extraction recovery of PUHs from water samples. Gradient elution was performed to analyse the extracted PUHs by high performance liquid chromatography (HPLC) with UV-photodiode array detection. Acceptable matrix effect was observed using the proposed LMA-HEDA-based dSPE-HPLC-UV for determining PUHs in environmental water samples. Relatively low detection limits (0.027–0.053 ng mL^?1) and good linearity (0.1–4.0 ng mL^?1; r² > 0.999) for individual PUHs were obtained using the proposed method. The proposed method offered detection limits lower than the allowed permissible level (0.1 ng mL^?1) set by European Union. The enrichment factors of target PUHs were also estimated at 40.3–47.7. Good extraction recoveries (80.1–97.9%) for PUHs-spiked water samples were obtained with relative standard deviations lower than 8.7%. The intra-day/inter-day precision (0.7–4.6%/0.2–5.9%) and accuracy (96.7–104.2%/95.3–103.6%) of the proposed method were also evaluated in this study. In addition, the applicability of the developed method was demonstrated by the measurement of PUHs in various environmental water samples.     

Development of ultrasound-assisted emulsification microextraction for the determination of triazine herbicides in environmental water samples by high-performance liquid chromatography

A simple, rapid, efficient, and environmentally friendly method for the determination of some triazine herbicides (simazine, atrazine, prometone, ametryn and prometryne) in water samples was developed by ultrasound-assisted emulsification microextraction (USAEME) coupled with high-performance liquid chromatography-diode array detection (HPLC-DAD). The main parameters that affect the extraction efficiencies, such as the kind and volume of the extraction solvent, ultrasound emulsification time and salt addition, were investigated and optimized. Under the optimum conditions, the method was sensitive and showed a good linearity within a range of 0.5 to 200?ngm?L^?1 for simazine, atrazine, prometone, ametryn and prometryne, with the correlation coefficients (r) varying from 0.9993 to 0.9998. High enrichment factors were obtained ranging from 148 to 225. The limits of detection (LODs) were in the range between 0.06 and 0.1?ngm?L^?1 and the limits of quantification (LOQs) were in the range between 0.2 and 0.3?ngm?L^?1. The recoveries of the analytes from water samples at spiking levels of 5.0 and 50.0?ngm?L^?1 were ranged from 82.4% to 107.0%. The relative standard deviations (RSDs) varied from 3.0% to 4.6%. The results demonstrated that the USAEME-HPLC-DAD method was an ef?cient pretreatment and enrichment procedure for the determination of triazine pesticides in real water samples.     

基于混合固定相色谱柱的SPE-HPLC法检测环境水体中三嗪类除草剂

利用混合固定相色谱柱(Optimix SCX/C8)分析了8种三嗪类化合物,在0.01 mol/L乙酸钠缓冲溶液(pH4.2)-CH3CN(75：25,V/V)等度洗脱的流动相条件下,实现了利用液相色谱方法分离同分异构体敌草净和西草净,并对比了相同色谱条件下8种目标物在C8色谱柱上的分离效果;比较了PEP和C18固相萃...     

Ion chromatography for the analysis of glyphosate and its selected metabolites. A review

Among all known compounds with herbicide activity glyphosate, has been the most commercially successful one. Currently, it is under evaluation because of its possible cancerogenic properties. However, the question is—if it is possible to completely withdraw it from use. Before it can happen, it is important to be sure of all its benefits and limitations, and this requires further detailed research. Due to the extent and prevalence of its use, glyphosate ends up in the environment and then in food and our bodies. There are several methods used for their determination. One of them is ion chromatography. Taking into account its advantages and disadvantages, as well as its rapid development, their importance in this field can be expected to increase in the near future. This paper summarizes the literature data from the past 22 years. The applications of ion chromatography in the determination of glyphosate in various types of environmental, food, and other samples are described. Moreover, the methods used so far are compared with the possibilities offered by ion chromatography, which main advantages and benefits are easy availability, low operating costs, green chemistry aspects, and suitable validation parameters.     

Application of phosphonium deep eutectic solvents as extractants in ultrasound-assisted dispersive liquid–liquid microextraction for preconcentration of trace amounts of herbicides in drainage ditches waters

In this study, an efficient preconcentration method was presented that is based on dispersive liquid-liquid microextraction taking the advantage of newly synthesized phosphonium deep eutectic solvents used as extractants and ultrasound probe as a dispersing agent. The extracts obtained were analyzed by high-performance liquid chromatography. To optimize the five most important factors for the microextraction procedure a central composite design plan was used. Under optimal conditions (140 μl of extractant, 60 mg of NaCl, pH = 2.0, 120 s of extraction time with ultrasound probe as the dispersing agent, 16 min of centrifugation for phase separation), the proposed method allowed to achieve good precision with RSD between 3.2% and 9.7% at 1.0, 5.0 and 40.0 ng ml levels. The preconcentration factors were equal to 42, 39, and 41, and the limits of detection 0.128, 0.103, and 0.135 ng/ml for dicamba, 2-methyl-4-chlorophenoxyacetic acid, and 2-methyl-4-chlorophenoxypropionic acid, respectively. The proposed method was successfully applied for the determination of chlorophenoxy acid herbicides in water samples from drainage ditches with a good recovery in the range of 70%–93%.