固相萃取-高效液相色谱法测定水样中硝基苯类化合物

建立了固相萃取-高效液相色谱法测定水样中5种硝基苯类化合物,硝基苯、2,4,6-三硝基甲苯、2,4-二硝基氯苯、邻一硝基氯苯和对-硝基氯苯的方法.对固相萃取,水样预处理和色谱分离条件做了试验并予以优化.采用Porapak RDX固相萃取柱将样品浓缩富集后,以C<,18>色谱柱(250 mm×4.6 mm,5μm)为分离柱,以甲醇和水以体积比55比45的混合液为流动相,在检测波长为260 nm处进行测定.方法检出限(2S/N)为0.8～1.8μg·L-1,相对标准偏差(n=7)在1.1 9/6～5.6%之间,加标回收率在81.5%～101.0%之间.该方法已用于地表水及生活饮用水中的硝基苯类化合物测定.     

气相色谱法测定饮用水及其源水中灭草松和2,4-滴

采用气相色谱ECD检测器同时分离检测水中灭草松和2,4-滴两种农药.水样中灭草松和2,4-滴在酸性条件下经乙酸乙酯萃取,然后用碘甲烷溶液酯化,生成较易挥发的甲基酯类衍生物,用毛细管气相色谱-电子捕获检测器分离测定.对衍生方式、温度和时间进行了优化,分别使用ECD和FPD检测器测定灭草松,而ECD检测灵敏度高.本法的最低检测质量浓度为灭草松0.15 μg/L,2,4-滴0.050 μg/L.方法灵敏度和精密度均满足分析要求.     

HPLC-DAD法分析硝基化合物的影响因素EI北大核心CSCD

利用液相色谱对邻硝基甲苯、间硝基甲苯、对硝基甲苯、硝基苯、1,3,5-三硝基苯、2,4-二硝基甲苯、2,6-二硝基甲苯、环三亚甲基三硝胺、环四次甲基四硝胺、2,4,6-三硝基甲苯10种硝基化合物进行了分离,研究了色谱柱温度、流动相成分和流速对分离效果的影响。升高色谱柱温度或加快流动相流速都会使化合物的分离度变差。流动相成分的变化对各化合物分析的影响较大,不仅会改变化合物的分离度,还会使吸收波长发生移动。色谱柱为Zorbax Eclipse XDB-C_(18)(4.6×250 mm,5μm),色谱柱温度≤30℃、流动相为甲醇:水=55:45(V/V)、流速在0.6~1.2 m L/min时10种硝基化合物可以达到较好的分离。     

HPLC-DAD法分析硝基化合物的影响因素

利用液相色谱对邻硝基甲苯、间硝基甲苯、对硝基甲苯、硝基苯、1,3,5-三硝基苯、2,4-二硝基甲苯、2,6-二硝基甲苯、环三亚甲基三硝胺、环四次甲基四硝胺、2,4,6-三硝基甲苯10种硝基化合物进行了分离,研究了色谱柱温度、流动相成分和流速对分离效果的影响。升高色谱柱温度或加快流动相流速都会使化合物的分离度变差。流动相成分的变化对各化合物分析的影响较大,不仅会改变化合物的分离度,还会使吸收波长发生移动。色谱柱为Zorbax Eclipse XDB-C_(18)(4.6×250 mm,5μm),色谱柱温度≤30℃、流动相为甲醇:水=55:45(V/V)、流速在0.6~1.2 m L/min时10种硝基化合物可以达到较好的分离。     

气相色谱内标法测定饮用水中氯乙酸及不确定度评定

采用气相色谱内标法对氯化消毒的饮用水进行氯乙酸残留测定。水样经过液液萃取以后,加入甲醇-浓硫酸溶液衍生2 h,取上清液测定。以1,2-二溴丙烷为内标,用DB-1(0.25mm×0.25μm×30m)的毛细管柱进行分离,电子捕获(ECD)检测器检测,并依据JJF1059-1999对检测结果进行不确定度评定和表示。方法线性良好(相关系数R2=0.9995和0.9971),平均加标回收率为100%~120%,重现性好。不确定度评定结果显示不确定度主要来自标准品的纯度和体积。     

气相色谱-电子捕获检测法测定食品包装材料中2,4-二氨基甲苯

建立了食品包装复合材料中2,4-二氨基甲苯的气相色谱-电子捕获检测(GCECD)方法。分析条件为:HP-5毛细管气相色谱柱(30m×0.32mm×0.25μm);载气流速0.8mL/min;进样口温度为260℃,分流比为5∶1;ECD检测器温度:300℃;柱温:170℃;进样量:1μL。2,4-二氨基甲苯浓度在0.02~1mg/L范围内与色谱峰面积线性良好,相关系数为0.9991,方法检出限(S/N=3)为0.001mg/L。     

气相色谱法测定水样中硝基苯类化合物含量

提出了气相色谱法测定水样中硝基苯类化合物的含量的方法。水样经乙酸乙酯-苯-乙醚(2+1+0.02)混合溶剂提取,采用HP-1701毛细管色谱柱(30m×0.25mm,0.25μm)分离,用微电子捕获检测器测定。9种硝基苯类在11.5min内达到完全分离,其线性范围在质量浓度0.001～5.0mg.L-1之间。方法的回收率在92.0%～108%之间,测定结果的相对标准偏差(n=5)均小于5.0%。     

顶空气相色谱法同时测定生活饮用水中17种挥发性卤代烃

建立了顶空气相色谱法同时测定生活饮用水中17种挥发性卤代烃的分析方法。样品采用自动顶空进样技术，经DB–5毛细管色谱柱（30 m×0.32 mm,0.25μm）分离后，用电子捕获检测器检测。优化样品保存条件为加入0.5 g抗坏血酸，冷藏避光保存。优化顶空条件：平衡温度为70℃，平衡时间为30 min,NaCl添加量为2.5 g。使用4-溴氟苯作为质控物质，保证测定结果的准确性。17种挥发性卤代烃的标准曲线相关系数均不小于0.998，方法检出限为0.003～2μg/L，平均回收率为85.7%～105.7%，测定结果的相对标准偏差为1.0%～5.6%(n=6)。该方法快速、灵敏度高、重现性好，适用于生活饮用水中17种挥发性卤代烃的同时测定。     

固相萃取-毛细管气相色谱法测定生活饮用水中16种硝基苯类化合物

建立了生活饮用水中16种硝基苯类物质的固相萃取-毛细管气相色谱-电子捕获检测方法.实验优化了色谱柱、升温程序等色谱条件,并对影响固相萃取效果的主要因素(萃取小柱、洗脱剂和洗脱体积)进行了考察.水样中16种硝基苯类物质经Oasis HLB固相萃取柱吸附、正己烷-丙酮(3∶1,V/V)洗脱后,采用DB-1701毛细管气相色谱柱程序升温分离、ECD检测,在33 min内完成所有待测组分的测定.16种硝基苯类组分在各自的线性范围内相关系数r≥0.998,方法的检出限为0.01 ～0.77 μg/L(S/N=3),定量限为0.03 ～2.57 μg/L(S/N=10),日内精度和日间精度分别在1.0％ ～ 3.8％和2.3％～4.8％间,样品加标回收率为83.6％～ 111.8％,加标样品的RSD为1.2％ ～5.1％.应用本方法对50份水样进行了分析,结果表明,本方法准确、灵敏、快速,适用于水质的常规分析,可为水样中硝基苯类物质的污染评价提供技术支持.     

分散液相微萃取-气相色谱/质谱快速分析水中的硝基苯类化合物

建立了分散液相微萃取.气相色谱,质谱快速分析水中硝基苯、对硝基苯、1,3一二硝基苯和2,4-二硝基氯苯的新方法.将含有18μL氯苯(萃取荆)的0.25 mL丙酮(分散剂)作为萃取体系,快速注入到5.0 mL水溶液中.在4000r/min下离心2.0 min后,得到(10.0±0.5)μL沉积相(氯苯),取底部沉积相1.0μL进行气相色谱,质谱分析.方法线性范围0.5～50μg/L(r2=0.9986～0.9994),检出限0.2～0.5μg/L,相对标准偏差4.2%～7.3%(n=5).将该方法用于环境水样的测定,加标回收率72.9%～89.6%.     

顶空-气相色谱法同时测定饮用水中八种挥发性苯系物

利用顶空-毛细管柱气相色谱技术对饮用水中的苯、甲苯、乙苯、邻二甲笨、对二甲笨、间二甲笨、异丙苯、苯乙烯的测定方法进行了研究,并对平衡时间、气／液体积比、水中含盐量等影响测定因素进行了探讨,对色谱条件和顶空进样条件进行了优化。该方法选用HP-INNOWAX色谱柱,使一直较难分离的间、对二甲苯得到了很好的分离。对八种苯系物进行了最低检出限、线性、回收率、精密度试验,其平均回收率为97．4％～1063％（n=7）,相对标准偏差为2．55％～3．83％（n=7）,最低检出限为0．06～0．10μg／L。测定结果表明,该法操作简单,重现性好,灵敏度高,完全可以满足饮用水中挥发性苯系物的测定。     

顶空固相微萃取-气相色谱-质谱法同时测定饮用水源水中24种VOCs

建立了同时测定饮用水源水中24种挥发性有机物(VOCs)的顶空固相微萃取-气相色谱-质谱法.用75 μm CarboxenTM-Polydimethylsiloxane(CAR-PDMS)固相微萃取柱顶空萃取水样中的VOCs,VOCs用气相色谱-质谱联用仪检测,采用内标法定量.对萃取柱涂层、样品盐度、萃取温度和萃取时间等样品前处理条件进行了优化,VOCs的检出限在0.03～0.31 μg/L之间,线性相关系数r＞0.996(二氯甲烷和三氯甲烷除外).对饮用水源水实际水样0.50μg/L和1.00 μg/L两个加标浓度水平的回收率进行了测定,三氯甲烷回收率均值分别为104％和142％,其余VOCs回收率分别为90.0％～120％和88.0％～110％,除二氯甲烷和三氯甲烷外,其余VOCs测定结果的相对标准偏差均小于15.0％(n=6).该方法适用于饮用水源水中挥发性有机物的监测分析.     

顶空毛细管柱气质联用法测定饮用水中15种挥发性有机物

采用顶空毛细管柱GC–MS法测定饮用水中卤代烃、苯系物、氯苯等15种挥发性有机物。色谱柱为DB–624石英毛细管柱(60 m×0.25 mm,1.8μm),程序升温,直接进样顶空毛细管柱气质联用法同时测定饮用水中15种挥发性有机物。该方法具有良好的线性,线性相关系数均大于0.996。方法的检出限为0.10~0.22μg/L。15种挥发性有机物的平均回收率在94%~103%之间,测定结果的相对标准差为2.9%~6.7%(n=7)。该方法简便、快速,检测结果均能满足GB 5749–2006检测要求。     

直接进样–超高效液相色谱串联质谱法同时测定水源水中9种农药

建立直接进样–超高效液相色谱三重四级杆质谱联用(UPLC–MS–MS)快速测定水源水中9种痕量农药残留的方法。水样无需富集,经超高效液相色谱分离,串联三重四级杆质谱检测,在7.5 min内完成9种目标化合物的分析。9种农药的检出限(S/N≥3)在0.01~1.4μg/L之间,在各自的考察浓度范围内线性关系良好(r≥0.995)。在1.0~80μg/L添加水平内,实际样品的平均加标回收率为66.2%~114.0%,测定结果的相对标准偏差为2.3%~20.4%(n=6)。该法操作简便,重现性好,可用于饮用水源水中农药残留的快速测定。     

Determination of pesticide residues and related compounds in water and industrial effluent by solid-phase extraction and gas chromatography coupled to triple quadrupole mass spectrometry

Pollution of drinking water supplies from industrial waste is a result of several industrial processes and disposal practices, and the establishment of analytical methods for monitoring organic compounds related to environmental and health problems is very important. In this work, a method using solid-phase extraction (SPE) and gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS) was developed and validated for the simultaneous determination of pesticide residues and related compounds in drinking and surface water as well as in industrial effluent. Optimization of the method was achieved by using a central composite design approach on parameters such as the sample pH and SPE eluent composition. A single SPE consisting of the loading on a polymeric sorbent of 100 mL of sample adjusted to pH 3 and elution with methanol/methylene chloride (10:90, v/v) permitted the obtaining of acceptable recoveries in most cases. The concentration factor associated with sensitivity of the chromatographic analysis permitted the achievement of the method limit of detection values between 0.01 and 0.25 μg L^?1. Recovery assays presented mean recoveries between 70 and 120 % for most of the compounds with very good precision, despite the different chemical nature of the compounds analyzed. The selectivity of the method, evaluated through the relative intensity of quantification and qualification ions obtained by GC-QqQ-MS/MS, was considered adequate. The developed method was finally applied to the determination of target analytes in real samples. River water and treated industrial effluent samples presented residues of some compounds, but no detectable residues were found in the drinking water samples evaluated.     

气相色谱-串联质谱法测定船用燃料油中的9种含氮化合物

采用气相色谱-串联质谱(GC-MS/MS)法建立了船用燃料油中9种含氮化合物的测定方法。样品以SPE小柱净化去除饱和烃后,通过二氯甲烷-乙醇(5∶1)溶液洗脱。用DB-5MS(30 m×0.25 mm×0.25μm)色谱柱分离,采用多反应监测(MRM)模式,外标法定量。结果表明,9种含氮化合物的色谱分离效果良好,在浓度1~1 000 mg/kg范围内与峰面积均呈线性关系。方法的定量下限(S/N=10)为0.18~0.43 mg/kg,平均加标回收率为85.3%~121.6%,相对标准偏差(RSD,n=6)均不大于6.8%。结果表明该方法快速可靠、准确简便,适用于船用燃料油中9种含氮化合物的检测。     

离子色谱法测定饮用水中6种阴离子

建立生活饮用水中F~–,Cl~–,PO_3^(3–),PO_4^(3–),SO_3^(2–),SO_4^(2–)6种阴离子的离子色谱检测法。采用戴安DX–120型离子色谱仪及Ion Pac AS9–HC(250 mm×4.0 mm)阴离子交换柱,以5.0 mmo L/L Na_2CO_3–0.6 mmo L/L NaHCO_3溶液为淋洗液,流量为1.2 mL/min。6种阴离子的质量浓度与其色谱峰面积呈良好的线性关系,相关系数为0.999 3~0.999 8,检出限为0.026 4~0.741 4μg/mL(S/N=3)。水样的加标回收率为91.3%~110.0%,测定结果的相对标准偏差为1.65%~3.07%(n=6)。该方法具有操作简单,选择性、准确性好等优点,能够满足饮用水中F~–,Cl~–,PO_3^(3–),PO_4^(3–),SO_3^(2–),SO_4^(2–)6种阴离子的测定要求。     

Application of continual injection liquid‐phase microextraction method coupled with liquid chromatography to the analysis of organophosphorus pesticides

A liquid‐phase microextraction coupled with LC method has been developed for the determination of organophosphorus pesticides (methidation, quinalphos and profenofos) in drinking water samples. In this method, a small amount (3 μL) of isooctane as the acceptor phase was introduced continually to fill‐up the channel of a 1.5 cm polypropylene hollow fiber using a microsyringe while the hollow fiber was immersed in an aqueous donor solution. A portion of the acceptor phase (ca. 0.4 μL) was first introduced into the hollow fiber and additional amounts (ca. 0.2 μL) of the acceptor phase were introduced to replenish at intervals of 3 min until set end of extraction (40 min). After extraction, the acceptor phase was withdrawn and transferred into a 2 mL vial for a drying step prior to injection into a LC system. Parameters that affect the extraction efficiency were studied including the organic solvent, length of fiber, volume of acceptor and donor phase, stirring rate, extraction time, and effect of salting out. The proposed method provided good enrichment factors of up to 189.50, with RSD ranging from 0.10 to 0.29%, analyte recoveries of over 79.80% and good linearity ranging from 10.0 to 1.25 mg/L. The LOD ranged from 2.86 to 82.66 μg/L. This method was applied successfully to the determination of organophosphorus pesticides in selected drinking water samples.     

固相萃取–气相色谱法测定饮用水中5种有机磷农药

建立了固相萃取–气相色谱法测定饮用水中敌敌畏、乐果、甲基对硫磷、马拉硫磷及对硫磷的方法。采用Cleanert PEP–SPE固相萃取柱,以二氯甲烷、乙酸乙酯、甲醇及纯水活化固相萃取柱,以5 m L/min流量富集水样,然后用二氯甲烷及乙酸乙酯洗脱浓缩后进行气相色谱分析。5种有机磷农药线性相关系数均大于0.995,方法测定下限为0.16~0.80μg/L,加标回收率为59.8%~109.0%,测定结果的相对标准偏差小于16%(n=6)。该方法灵敏度高,准确度好,适用于饮用水中5种有机磷农药的检测。     

Determination of Ethylenethiourea (ETU) at Trace Levels in Water Samples by Cathodic Stripping Voltammetry

A stripping voltammetric method for the determination of ethylenethiourea in water samples is described based on its adsorptive deposition at the hanging mercury drop electrode (HMDE). In a borate buffer (pH 9.0) as supporting electrolyte, ETU is deposited at +100 mV (vs. Ag/AgCl) and stripped during the cathodic scan. The linear range for the measurements was from 2.0 to 100 μg L^?1, with a detection limit calculated as 1.4 μg L^?1 after a deposition time of 300 s and a RSD of 1.9% (n=5) for 50 μg L^?1 of ETU measured. The interferences of some organic compounds and metallic ions were tested. Recoveries between 93 and 110% were obtained using the standard addition method for spiked samples of natural and drinking waters. The method is rapid and applicable in the monitoring of ETU residues in water samples.