Ionic‐liquid‐functionalized magnetic particles as an adsorbent for the magnetic SPE of sulfonylurea herbicides in environmental water samples

In this paper, a new ionic‐liquid‐functionalized magnetic material was prepared based on the immobilization of an ionic liquid on silica magnetic particles that could be successfully used as an adsorbent for the magnetic SPE of five sulfonylurea herbicides (bensulfuron‐methyl, prosulfuron, pyrazosulfuron‐ethyl, chlorimuron‐ethyl and triflusulfuron‐methyl) from environmental water samples. The main parameters affecting the extraction efficiency such as desorption conditions, sample pH, extraction time and so on, were optimized using the Taguchi method. Good linearities were obtained with correlation coefficients ranging from 0.9992 to 0.9999 in the concentration range of 0.1–50 μg L^?1 and the LODs were 0.053–0.091 μg L^?1. Under the optimum conditions, the enrichment factors of the method were 1155–1380 and the recoveries ranged from 77.8 to 104.4%. The proposed method was reliable and could be applied to the residue analysis of sulfonylurea herbicides in environmental water samples (tap, reservoir and river).     

Analysis of herbicides in water using temperature-responsive chromatography and an aqueous mobile phase

A simple and rapid method has been developed for herbicides in water using temperature-responsive liquid chromatography (LC) and a column packed with poly(N-isopropylacrylamide) (PNIPAAm), a polymer anchored on the stationary-phase surface of modified silica. PNIPAAm reversibly changes its hydrophilic/hydrophobic properties in water in response to temperature. The method was used to determine five sulfonylurea and three urea herbicides. Separation was achieved with a 10 mM ammonium acetate (pH 3.0) isocratic aqueous mobile phase, and by changing the column temperature. The analytes were extracted from water by off-line solid-phase extraction (SPE) with an N-vinyl-pyrrolidone polymer cartridge. The average recoveries of the eight herbicides from spiked pure water, tap water and river water were 70-130% with relative standard deviations (RSDs) of <10%. The limits of quantitation (LOQ) of the eight herbicides were between 1 and 4 microg l(-1).     

Development and validation of a solid-phase extraction method coupled to high-performance liquid chromatography with ultraviolet-diode array detection for the determination of sulfonylurea herbicide residues in bovine milk samples

This study proposes a fast, simple and sensitive liquid chromatography diode array detector (LC/UV-DAD)-based method for the simultaneous determination of eight sulfonylurea herbicides (bensulfuron methyl, chlorsulfuron, metsulfuron methyl, primisulfuron methyl, rimsulfuron, thifensulfuron methyl, triasulfuron and tribenuron methyl) in bovine whole milk at concentrations lower than the default limit of 0.01 mg kg(-1) allowed by current legislation (Regulation EC/396/2005 and following Annexes). An effective one-step solid phase extraction (SPE) and clean up procedure was defined with use of Chem Elut cartridges, providing good recoveries for all the analytes tested and with no matrix effects affecting method accuracy. Separation of herbicides was obtained on a C(18) column by acetonitrile- water gradient elution. Method validation has been performed according to European Commission Decision 2002/657/EC criteria, in terms of linearity, recovery, precision, specificity, decision limit (CC(α)) and detection capability (CC(β)). Typical recoveries ranged between 78.4% and 99.7%, at the maximum residue limits (MRLs) levels established by Regulation EC/396/2005, with relative standard deviations (RSD) no larger than 10%.     

基于十八烷基三甲基溴化铵修饰的磁性粒子在线磁性固相萃取-高效液相色谱法测定水样中磺酰脲类农药

采用溶胶-凝胶法制备表面修饰了十八烷基三甲基溴化铵的磁性粒子作为萃取剂，研制了一种在线磁性固相萃取（on-line MSPE）装置，建立了on-line MSPE与高效液相色谱联用测定水样中两种磺酰脲类农药（氯磺隆、苄嘧磺隆）的方法。实验优化了在线磁性固相萃取条件并进行方法学考察，证明该方法具有良好的线性关系（两种目标物的线性相关系数均≥ 0.9997）和较低的检出限（两种目标物的检出限分别为0.32和1.12 μg/L）。将此法用于3种环境水样中两种磺酰脲类农药的检测，水样中均检出氯磺隆，均未检出苄嘧磺隆。两种目标物加标回收率为70.0%~113.4%。该方法高效、简便，在分离富集环境水样中磺酰脲类农药方面有一定的应用前景。     

Determination of five sulfonylurea herbicides in environmental waters and soil by ultra high performance liquid chromatography with tandem mass spectrometry after extraction using graphene

A fast and novel analytical method was developed for the determination of trace levels of sulfonylurea herbicides in water and soil samples. Graphene was used as a sorbent for extraction, and ultra high performance liquid chromatography with tandem mass spectrometry was used for quantification. Five sulfonylurea herbicides were preconcentrated from water samples using a graphene‐loaded packed cartridge, while extraction from soil samples was performed in a single step using graphene‐supported matrix solid‐phase dispersion. Under the optimized conditions, the calibration plots were linear in the range between 5 and 1000 ng/L for water samples, and between 1 and 200 ng/g for soil samples. All correlation coefficients (R) were >0.99. The limits of detection for water and soil samples were 0.28–0.53 ng/L and 0.08–0.26 ng/g, respectively. This method was successfully applied to the analysis of spiked samples of environmental water and soil, with recoveries ranging from 84.2–109.3 and 86.12–103.2%, respectively, all with relative standard deviations of <10%.     

Determination of sulfonylurea herbicides in water using solid-phase extraction followed by liquid chromatography with electrospray ion trap mass spectrometry

A method has been developed for confirmation and quantitation of ten sulfonylurea herbicides (nicosufuron, thifensulfuron-methyl, metsulfuron-methyl, sulfometuron-methyl, chlorsulfuron, ethametsulfuron-methyl, tribenuron, bensulfuron-methyl, pyrazosulfuron-ethyl and chlorimuron-ethyl) in water samples. Herbicides were extracted from water by off-line solid-phase extraction (SPE). Different types of absorbents were evaluated: silica-based ODS-C₁₈ and two polymeric sorbents, Cleanert HXN and Oasis HLB. Analyte determination and quantitation was performed by liquid chromatography with electrospray mass spectrometry (LC-ESI-MS) instrumentation, equipped with ion trap mass filter. Confirmatory analysis was carried out by LC/MS/MS. MS data acquisition was performed by a single or two-ion extracted ion monitoring program. The ten herbicides were measured in fortified tap water. Average recoveries of the nine analytes (except for tribenuron) from water samples were in the range of 77–109%, and the RSD ranged from 0.3 to 14.5%. The limit of detections (LODs) varied from 6 to 34.8 ng/L.     

液相色谱-电喷雾串联质谱法测定生姜中的215种农药残留

建立了生姜中215种农药多残留测定的液相色谱-电喷雾串联质谱(LC-ESI-MS/MS)方法。样品用1%醋酸-乙腈溶液均质提取,经Sep-Pak Vac固相萃取柱净化,乙腈-甲苯(3:1, v/v)洗脱,旋转蒸发浓缩至约0.5 mL后,于室温氮气吹干,用乙腈-水(3:2, v/v)溶解,以电喷雾电离串联质谱在正离子多反应监测(MRM)模式下进行测定。在定量限水平进行添加回收率实验,方法的回收率范围为68.1%～132.6%,其中回收率在70%～120%的占94.4%,相对标准偏差(RSD)范围为0.4%～25.0%。方法的检出限(S/N=3)和定量限(S/N=10)范围分别为0.01～70.45 μg/L和0.04～234.84 μg/L。该方法操作简便,灵敏度、准确度和精密度均符合农药多残留检测技术要求,适用于生姜中215种农药多残留的快速测定。     

Automated sample preparation using supported liquid membranes for liquid chromatographic determination of sulfonylurea herbicides

Summary Sample preparation for determination of sulfonylurea herbicides in aqueous samples is investigated. The technique studied utilizes extraction and back extraction in an automated flow system and is coupled on-line to a liquid chromatographic system. The extraction unit consists of an immobilized liquid membrane, separating two aqueous phases. From the acidified donor phase the analytes are extracted into the organic solvent of the membrane. After traversing the membrane they are back extracted into an alkaline/neutral aqueous acceptor phase. They are trapped in the acceptor by dissociation, making them insoluble in the membrane.Studies of the sample preparation system concern factors like channel length of separators, distribution coefficients of analytes and use of a precolumn instead of loop for chromatographic injections. Effects of the internal diameter of the analytical column as well as the detection of the sulfonylurcas are investigated.     

Determination of nerve agent degradation products in environmental samples by liquid chromatography-time-of-flight mass spectrometry with electrospray ionization

A powerful and rapid method has been developed for the identification and quantitative determination of alkyl methylphosphonic acids, which are the degradation products of nerve agents, using liquid chromatography-time-of-flight mass spectrometry with electrospray ionization. Six alkyl methylphosphonic acids were well separated within 16 min. For quantitative analysis, good linearity, sensitivity and reproducibility were obtained by LC-MS in the selected ion monitoring mode. For unambiguous identification of alkyl methylphosphonic acids, fragment ions were produced by in-source collision induced dissociation (CID), and then exact mass measurement of CID fragment ions was performed. The feasibility of applying this technique for detecting these compounds in spiked environmental waters and soils was demonstrated.     

High efficiency packed column supercritical fluid chromatography of sulfonylurea herbicides and metabolites from large water samples

Summary Five sulfonylurea herbicides were separated by SFC on both a 25 cm and a 1.6 meter packed column. The former produced rapid analysis, the latter allowed high resolution of a complex mixture containing the solutes of interest. The solutes were simultaneously detected with UV, nitrogen-phosphorus (NPD), and electron capture (ECD) detectors. Peaks of breakdown products of sulfonylureas were characterized by their UV spectra and the presence or absence of nitrogen and chlorine from their NPD and ECD response. Both parent and breakdown products of sulfonylureas were on-line extracted from large water samples with detection limits as low as 50 parts per trillion.     

High efficiency packed column supercritical fluid chromatography of sulfonylurea herbicides and metabolites from large water samples

Summary Five sulfonylurea herbicides were separated by SFC on both a 25 cm and a 1.6 meter packed column. The former produced rapid analysis, the latter allowed high resolution of a complex mixture containing the solutes of interest. The solutes were simultaneously detected with UV, nitrogen-phosphorus (NPD), and electron capture (ECD) detectors. Peaks of breakdown products of sulfonylureas were characterized by their UV spectra and the presence or absence of nitrogen and chlorine from their NPD and ECD response. Both parent and breakdown products of sulfonylureas were on-line extracted from large water samples with detection limits as low as 50 parts per trillion.     

高效液相色谱-电喷雾串联质谱法检测环境水样中22种抗生素类药物

建立了高效液相色谱-电喷雾串联质谱(HPLC-ESI MS/MS)分析环境水样中22种抗生素类药物的方法。采用HLB固相萃取柱对环境水样中的目标化合物进行富集、净化,然后以6 mL氨水-甲醇(5:95, v/v)溶液洗脱。收集的洗脱液经氮气吹干至1 mL,然后进行HPLC-ESI MS/MS分离分析。色谱流动相A相为甲醇-乙腈(1:1, v/v), B相为0.3%(体积分数)甲酸水溶液(含0.1%(体积分数)甲酸铵,pH 2.9);色谱柱为XTerra MS C18柱。质谱检测采用正离子扫描,多反应监测模式。分别以自来水和污水作为基质,22种抗生素类药物的加标平均回收率分别为54.9%～130%和57.4%～138%,相对标准偏差(n=3)分别为2.85%～28.6%和2.02%～23.2%;方法的检出限为0.05～0.5 ng/L。将建立的方法应用于北京市高碑店湖和小清河水样的分析,结果表明在两个水样中均有部分抗生素类药物检出。     

Selective magnetic solid-phase extraction of amide herbicides from fish samples coupled with ultra-high-performance liquid chromatography with tandem mass spectrometry

An efficient magnetic dummy template molecularly imprinted polymer nanocomposite was prepared using multi-walled carbon nanotubes as a support and metolachlor deschloro as a dummy template. The obtained nanocomposites were characterized using Fourier transform infrared spectroscopy, vibrating sample magnetometry, scanning electron microscopy, and transmission electron microscopy. The adsorption performance of the obtained nanocomposites was evaluated through binding experiments, including static adsorption, kinetic adsorption, and selective recognition studies. The obtained nanocomposites were successfully applied as selective sorbents for the magnetic solid-phase extraction of seven amide herbicides (alachlor, acetochlor, pretilachlor, butachlor, metolachlor, diethatyl ethyl, and dimethachlor) coupled with liquid chromatography-tandem mass spectrometry from fish samples. Under the optimized conditions, the limit of detection was 0.01–0.1 μg/kg. The obtained recoveries of the amide herbicides from the fish samples were in the range of 88.0 to 102.1% with a relative standard deviation of less than 7.5%. This method, which eliminated the effect of template leakage on qualitative and quantitative analysis was found to be superior to the methods reported in the literature. The results indicated that it could be successfully applied to analyze amide herbicides in fish samples with satisfactory recoveries.     

水体中甲硫嘧磺隆残留量的高效液相色谱法检测

采用Kromasil C18不锈钢柱(250mm×4.6mm i.d.,5μm),以V(甲醇)∶V(水)=70∶30混合溶剂为流动相(pH用H3PO4调至3.0),流速1.0mL/min,检测波长236nm和柱温35℃,建立了不同水体中甲硫嘧磺隆残留的样品处理方法和高效液相色谱分析方法。甲硫嘧磺隆在0.25~10mg/L范围内,其峰面积(Y)与质量浓度(ρ)呈现良好的相关性,其线性回归方程为Y=4425.9ρ 5664.8,R2=0.9997。在纯净水、池塘水、河水、稻田水A和稻田水B中,甲硫嘧磺隆5个添加浓度水平的平均回收率分别为92.80%~101.53%、92.54%~103.10%%、94.11%~97.57%、92.91%~101.25%和84.94%~92.53%,RSD分别为0.43%~4.1%、0.85%~6.5%、0.37%~7.0%、0.56%~7.7%和1.4%~4.7%,检出限(LOD)为1.50×10-9g(S/N=3)。可用于环境水样中甲硫嘧磺隆的残留量检测。     

Determination of diphenylether herbicides in water samples by solid-phase microextraction coupled to liquid chromatography

Solid-phase microextraction (SPME) coupled to LC for the analysis of five diphenylether herbicides (aclonifen, bifenox, fluoroglycofen-ethyl, oxyfluorfen, and lactofen) is described. Various parameters of extraction of analytes onto the fiber (such as type of fiber, extraction time and temperature, pH, impact of salt and organic solute) and desorption from the fiber in the desorption chamber prior to separation (such as type and composition of desorption solvent, desorption mode, soaking time, and flush-out time) were studied and optimized. Four commercially available SPME fibers were studied. PDMS/divinylbenzene (PDMS/DVB, 60 microm) and carbowax/ templated resin (CW/TPR, 50 microm) fibers were selected due to better extraction efficiencies. Repeatability (RSD, < 7%), correlation coefficient (> 0.994), and detection limit (0.33-1.74 and 0.22-1.94 ng/mL, respectively, for PDMS/DVB and CW/TPR) were investigated. Relative recovery (81-104% for PDMS/DVB and 83-100% for CW/TPR fiber) values have also been calculated. The developed method was successfully applied to the analysis of river water and water collected from a vegetable garden.     

液相色谱-电喷雾电离三重四级杆质谱测定畜禽肝脏中维吉尼亚霉素M1的残留量

建立了动物肝脏组织中维吉尼亚霉素M1残留的液相色谱-电喷雾电离三重四级杆质谱(LC-ESI-MS/MS)的测定方法。样品经0.2 mol/L NH4H2PO4和乙酸乙酯提取,分散型固相萃取PSA填料净化,采用正离子扫描多反应监测(MRM)模式下液质联用仪进行定性和定量分析。该方法省去耗时的固相萃取过程,回收率在67.2%～90.3%之间,RSD<10.0%;检测限为0.5μg/kg,定量限为1.0μg/kg。     

Determination of phthalate esters in cow milk samples using dispersive liquid-liquid microextraction coupled with gas chromatography followed by flame ionization and mass spectrometric detection

A simple and economic method for the analysis of phthalate esters, dimethyl phthalate, diethyl phthalate, di-iso-butyl phthalate, di-n-butyl phthalate, and di-2-ethylhexyl phthalate in cow milk samples by means of gas chromatography-flame ionization detection and gas chromatography-mass spectrometry has been developed. In this work, NaCl and ACN were added to 5 mL of the milk sample as the salting out agent and extraction solvent, respectively. After manual shaking, the mixture was centrifuged. In the presence of NaCl, a two-phase system was formed: upper phase - acetonitrile containing phthalate esters -and lower phase - aqueous phase containing soluble compounds and the precipitated proteins. After the extraction of phthalate esters from milk, a portion of supernatant phase (acetonitrile) was removed, mixed with 1,2-dibromoethane at microliter level and injected by syringe into NaCl solution. After the extraction of the selected phthalate esters into 1,2-dibromoethane, phase separation was performed by centrifugation and the enriched analytes in the sedimented phase were determined by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. Under the optimum extraction conditions, low limits of detection and quantification between 1.5-3 and 2.5-11 ng/mL, respectively was observed. Enrichment factors were in the range of 397-499. The relative standard deviations for the extraction of 100 ng/mL of each phthalate ester were in the range of 3-4% (n = 6). Finally, some milk samples were successfully analyzed using the proposed method and two analytes, di-n-butyl phthalate and di-2-ethylhyxel phthalate, were determined in them in nanogram per milliliter level.     

粮食中磺酰脲类除草剂的UPLC/MS/MS测定方法

建立了多类粮食作物中15种磺酰脲类除草剂的超高效液相色谱-串联质谱联用仪(UPLC/MS/MS)多离子监测(MRM)的多残留检测方法。样品经乙腈提取,乙腈饱和的正己烷液-液分配,石墨化碳氨基小柱净化,采用UPLC-MS/MS(ESI+)测定。方法中各种磺酰脲类除草剂在5～200μg/L浓度范围内线性良好,相关系数在0.9995～0.9999。在5～100μg/kg范围内,平均加标回收率在71.6%～115.3%之间,相对标准偏差不大于15%。各种药物的定量限(S/N≥10)均可达到5μg/kg。该方法可同时满足大豆、大米、玉米等多种粮食中磺酰脲类除草剂的检测需求。     

Determination of sulfonylurea herbicides in soil extracts by solid-phase extraction and capillary zone electrophoresis

Summary Sulfonylurea herbicides in soil extracts were concentrated using off-line solid-phase extraction (SPE), and determined by capillary zone electrophoresis (CZE) and UV detection. The method involves extraction of soils with 0.1 M NaHCO₃ solution and subsequent preconcentration by using C₁₈ cartridges prior to separation of the pesticide using CZE. The results show that a C₁₈ cartridge is suitable for the purification of sulfonylurea herbicides in soil extracts with the recoveries ranging from 65–103%. The separation conditions affecting the resolution and detection sensitivity was systematically investigated. The sulfonylureas were resolved well using 30 mM sodium acetate (NaAc)/acetic acid (HAc)+10% acetonitrile (ACN) buffer at pH 4.80. The calibration plots for the test solutes in the concentration of 0.2–50 mg L⁻¹ were linear with detection limits in the range of 0.05–0.10 mgL⁻¹. The proposed method has been successfully demonstrated for the determination of sulfonylurea herbicides in soil samples.     

Determination of triazine herbicide residues in water samples by on-line sweeping concentration in micellar electrokinetic chromatography

A new method for the determination of atrazine, simazine and prometryn in water samples by on-line sweeping concentration technique in micellar electrokinetic chromatography （MEKC） was developed. Various parameters affecting sample enrichment and separation efficiency were systematically studied. Compared with the conventional MEKC method, up to 60-200-fold improvement in concentration sensitivity was achieved in terms of peak height by using this sweeping injection technique. The compound strychnine was used as the internal standard for the improvement of the experimental reproducibility. The limits of detection （S/ N = 3：1） for atrazine, simazine and prometryn were 9, 10 and 0.5 ng mL-1, respectively. This method has been successfully applied to the analysis of atrazine, simazine and prometryn in lake, steam and ground water.