五氟苯甲酰氯衍生-气相色谱-质谱法测定地表水中一甲基肼

建立了五氟苯甲酰氯衍生-气相色谱-质谱法测定地表水中一甲基肼的方法。取200ml水样,调节后的pH为10,加入20ml衍生剂,在室温下剧烈振荡衍生1h,40ml二氯甲烷萃取10min,浓缩至1.0ml后用气相色谱-质谱联用分析。方法在5～500μg/L浓度范围内线性良好,相关系数大于0.996,方法检出限为2.67μg/L;加标水样的相对标准偏差为9.54%和8.38%;加标水样回收率为79.08%～102.96%。     

水中氯代酸性除草剂衍生气相色谱法主要要素探讨

建立了衍生气相色谱-负化学源质谱检测水中氯代酸性除草剂的方法,从四个方面对氯代酸性除草剂衍生气相色谱法中主要要素分析:针对不同需求选择确定萃取模式、萃取溶剂、酸度、浓缩方式等;对不同衍生方式进行比较,分析了辅助条件的必要性;针对衍生产物的不同选择离子源;标准物质的合理使用。     

醛类化合物检测方法中腙类物质的衍生条件

通过对醛类化合物的DNPH衍生化酸度、摩尔比、时间条件的研究和衍生化结果的验证获得了过量DNPH条件下制备15种醛的腙标准溶液制备方法。实验结果表明,其共同衍生化条件为1.0~2.0 mol/L盐酸溶液中DNPH/醛类摩尔比不小于2∶1条件下,醛类物质与DNPH可充分衍生化。     

高效离子色谱柱后衍生法测定环境水体中过渡金属离子含量

建立了可同时分析饮用水中铁、铜、镍、锌、钴、镉、锰等过渡金属离子的方法。优化后的离子色谱条件:选用 Dionex IonPac CS5A色谱柱(4 mm×250 mm),以7.0 mmol/L 吡啶-2,6-二羧酸＋66 mmol/L KOH＋74 mmol/L HCOOH＋5.6 mmol/L K₂SO₄为淋洗液,流速为1.2 mL/min,柱温为30 ℃;以0.5 mmol/L 4-(2-吡啶偶氮)间苯二酚＋1.0 mol/L 2-二甲醇胺＋0.5 mol/L氨水＋0.3 mol/L NaHCO₃为衍生液,流速为0.7 mL/min,紫外检测器波长为520 nm。结果表明,该离子色谱柱对以上过渡金属具有很好的保留和分离效果,衍生后的紫外检测手段具有优异的灵敏度和选择性。该方法稳定性良好,连续进样5针的相对标准偏差均小于0.79%;标准曲线线性关系良好,r≥0.998 8;方法检出限低,Fe³⁺为0.8 μg/L,Fe²⁺为4 μg/L,Cu²⁺为0.8 μg/L,Ni²⁺为3 μg/L,Zn²⁺为2 μg/L,Co²⁺为0.9 μg/L,Cd²⁺为16 μg/L,Mn²⁺为6 μg/L;检测结果准确,低、中、高3个水平的加标回收率均大于91.5%。该方法适用于环境水体中过渡金属离子的定量分析。     

衍生化气相色谱法测定环境水样中的多菌灵

通过对反应温度、时间等衍生化条件的优化研究,建立了环境水样中残留多菌灵的衍生化气相色谱氮磷检测方法。方法的最低检出浓度为0.10μg/L,样品加标回收率为83.2%～90.9%,相对标准偏差为4.6%。利用该方法能较好地满足GB 21523-2008《杂环类农药工业水污染物排放标准》中该杂环类农药的痕量测定要求。     

柱后衍生离子色谱法测定土壤和沉积物中的六价铬

采用加热回流提取、柱后衍生离子色谱法分离土壤和沉积物中的六价铬,使用紫外可见检测器进行测定。选用7种土壤和沉积物的实际样品,依次讨论了氢氧化钠-碳酸钠溶液、碳酸氢钠溶液、氢氧化钠-氯化钾溶液、离子色谱碱性淋洗液4种不同提取剂对六价铬的提取效率,以及超声提取、水浴振荡提取和恒温磁力搅拌冷凝回流3种提取方式的提取效果;研究了10～60 min、25～190℃条件下的最佳提取时间和加热温度;分析了不同提取剂体积和称样量比值条件下六价铬标土的测定量,并探究了提取液的保存条件。优化后的前处理条件：称取2.5 g筛分后的土壤或沉积物样品,加入25 mL NaOH/Na₂CO₃提取剂,在恒温磁力搅拌冷凝回流装置上于120℃加热回流60 min,离心后用0.22μm滤膜过滤,用柱后衍生离子色谱紫外检测装置进行测定。相比目前常用的分光光度法、原子吸收法等测定土壤中六价铬方法,柱后衍生离子色谱法特异性强,降低了差减法或其他前处理技术测定六价铬时所引入的误差,且不受提取液色度、浊度等影响。方法检出限可达0.002 mg/kg,灵敏度高,操作简便,抗干扰能力强,对于...     

水中草甘膦和氨甲基膦酸的柱前衍生-液相色谱方法研究

建立柱前衍生-液相色谱-荧光检测法同时测定水中草甘膦和氨甲基膦酸的方法。水样经芴甲氧羰酰氯衍生化后取上清液进样,采用ODS C18柱,以水(5 mmol/L乙酸铵)-乙腈作为流动相进行梯度洗脱,采用荧光检测器进行检测。实验通过加入柠檬酸三钠,解决了实际水样中金属阳离子的干扰问题。草甘膦和氨甲基膦酸在一定范围内线性良好(r=0.997 3~0.999 0),回收率为92.2%~102%,相对标准偏差为4.3%~8.5%,方法检出限为1.29μg/L和1.84μg/L。     

次氯酸钠衍生-气相色谱法测定水中苦味酸

采用次氯酸钠衍生、毛细管柱气相色谱电子捕获检测器测定水中苦味酸,选择正己烷为萃取剂,萃取时间5 min,衍生反应时间40 min。方法在5.00μg/L～100μg/L范围内线性良好,检出限为0.2μg/L,空白加标水样平行测定的RSD为2.2%,加标回收率为89.6%～95.0%。     

硬质聚氨酯泡沫和组合聚醚中消耗臭氧层物质的便携式GC-MS测定方法

建立了便携式顶空/气相色谱-质谱法测定硬质聚氨酯泡沫和组合聚醚中一氟三氯甲烷（CFC-11）、二氟二氯甲烷（CFC-12）、二氟一氯甲烷（HCFC-22）及一氟二氯乙烷（HCFC-141b）的定性分析方法,系统考察了色谱柱、顶空体系、顶空温度和顶空时间对测定结果的影响。结果表明,DB-WAX色谱柱对目标物质的分离效果最好,顶空温度为50℃、顶空时间为10 min条件下,目标物质的检测灵敏度最高。在优化条件下,硬质聚氨酯泡沫取样体积为1 cm³时,4种目标物的方法检出限为0.6~0.8 μg;组合聚醚取样量为10 mg时,4种目标物的方法检出限为0.5~0.6 μg。该方法具有较高的灵敏度,定性准确,适用于实际样品的现场快速定性分析。     

碱提取-丙基化衍生法同时测定土壤中的甲基汞和乙基汞

建立了碱提取-丙基化衍生方式同时测定土壤中甲基汞和乙基汞的方法。优化了仪器分析条件,研究了碱提取温度、提取时间、缓冲溶液加入量和衍生化试剂加入量对测定结果的影响。应用本方法对5种实际土壤样品进行测定,甲基汞和乙基汞的方法检出限分别为0.5 μg/kg和0.3 μg/kg,相对标准偏差分别为1.3%~17%和0.94%~16%,平均回收率分别为88.2%~110%和66.1%~110%。该法适用于批量土壤样品中甲基汞和乙基汞的分析测定。     

Determination of acetaldehyde in ambient air: comparison of thermal desorption-GC/FID method with the standard DNPH-HPLC method

In this work, the experimental compatibility between the standard DNPH-HPLC method and the gas chromatographic (GC) method (without any derivatization) was investigated for the analysis of atmospheric carbonyls. In the latter case, GC analysis was made based on adsorptive enrichment on solid sorbents followed by thermal desorption. For a comparative analysis between the two methods, we quantified the concentration levels of acetaldehyde from gaseous combustion samples of different charcoal products. The acetaldehyde concentration data, measured by the HPLC method (643 ± 1,689 ppb), were approximately 10% lower than the GC-based method (722 ± 1,788 ppb). As such, the differences in the measured concentrations were statistically insignificant. Although the percentage difference of the two methods fell within a relatively wide range, the results obtained by the GC-based method were comparable to those of the HPLC method with significantly strong correlations. The GC-based method, if tested for certain carbonyl species such as acetaldehyde, appeared to be a suitable alternative for the HPLC method.     

全自动甲基汞分析仪测定水和废水中甲基汞

建立了全自动甲基汞分析仪测定水和废水中甲基汞的方法,对较清洁的地表水和一般废水样品可直接衍生化测定,对基体复杂水样则需蒸馏后再衍生化测定。该法在水样中甲基汞含量为0~1 000 pg范围内线性良好,相关系数r为0.999 7,检出限为0.002 ng/L,标准参考物质测定结果均在参考值范围内,相对标准偏差为1.1%,加标回收率为83.2%~96.6%。该法适用于水及废水中甲基汞的检测。     

气相色谱法测定固定污染源废气中氯甲基甲醚和二氯甲基醚的研究

氯甲基甲醚(CMME)和二氯甲基醚(BCME)属于确认人类致癌物,因此,建立精准、绿色的CMME和BCME检测分析方法十分必要。基于2,4,6-三氯苯酚+乙醇钠+乙醇衍生化体系,利用气相色谱法(电子捕获检测器)测定了固定污染源废气中的CMME和BCME,并且系统地优化了采样条件、衍生化条件,确定了衍生化产物的结构及衍生比率。结果表明：工作曲线相关系数均大于0.990;当采样量为10 L时,检出限均为0.003 mg/m³;当实际样品加标量分别为0.010、0.100、1.00 mg/m³时,测定结果的相对标准偏差分别为15%～16%、8.9%～13%、10%～11%,加标回收率分别为89.2%～90.8%、75.3%～78.6%、76.5%～77.2%。     

Application of cryofocusing hydride generation and atomic fluorescence detection for dissolved mercury species determination in natural water samples

The concentration levels of mercury (Hg) species in natural water samples are usually low. Consequently, accurate analysis with low detection limits is still a major problem. In this work, a method was applied for the simultaneous direct determination of dissolved mercury species in water samples by on-line hydride generation (HG), cryogenic trapping (CT), gas chromatography (GC) and detection by atomic fluorescence spectrometry (AFS). The suitability of the method for real samples with different organic matter and chloride contents was evaluated by recovery experiments in synthetic and natural spiked water samples. The HG method was compared with other current available methods for mercury analysis with respect to the different fraction of mercury analysed, i.e. 'reactive', 'reducible' or total. HG derivatization and SnCl2 reduction (with and without previous oxidation with BrCl) were applied to synthetic and natural (spiked and non-spiked) water samples. The influence of chloride and dissolved organic matter concentrations was studied. The results suggest that the HG procedure is suitable for the simultaneous determination of Hg2+ and MeHg+ in surface water samples. Inorganic mercury analysed by HG (i.e. reducible) is close to the total inorganic mercury.     

水中乙醛和丙烯醛分析方法的对比

对测定水中乙醛和丙烯醛的3种方法——2,4-二硝基苯肼衍生化法、顶空气相色谱法和吹扫捕集一气相色谱质谱法进行概述和总结,并对各方法的试验条件、方法原理、测定影响因素以及效能验证等分析、比对,突出表现各自的优势和特点。用3种方法同时测定实际水样,结果无显著差异,精密度、准确度满足监测要求。     

毛细管气相色谱法测定鳌江表层沉积物中五氯酚和六氯苯

建立了超声波萃取-醋酸酐原位衍生化-毛细管气相色谱同时测定鳌江表层沉积物中五氯酚和六氯苯的方法,优化了试验条件。方法线性范围为5μg／L-200μg／L,五氯酚和六氯苯的检出限均为0．5ng／g,沉积物标准物质的测定值符合质控要求,基质加标的平均回收率分别为77．7％和81．8％。     

改进后EROD法与仪器分析法应用比对研究

环境二(恶)英类污染物受到广泛关注,目前常用的二(恶)英类物质检测方法有仪器分析法(高分辨率气相色谱-高分辨率质谱法)和生物检测法.生物检测法具有便捷高效、成本低廉等优点,但其测定值普遍高于仪器分析法,关键原因是生物检测法在前处理阶段未能完全消除非二(恶)英类物质的干扰.改进了传统7-乙氧基-3-异吩恶唑酮-脱乙基酶(...     

Simultaneous derivatization and extraction of nitrophenols in soil and rain samples using modified hollow-fiber liquid-phase microextraction followed by gas chromatography–mass spectrometry

A simple and sensitive method based on a modified hollow-fiber liquid-phase microextraction followed by gas chromatography–mass spectrometry has been successfully developed for the extraction and simultaneous derivatization of some nitrophenols (NPs) in soil and rain samples. Microwave-assisted solvent extraction was used for the extraction of NPs from the soil, while the rain sample was directly applied to the previously mentioned method. Briefly, in this method, the analytes were extracted from aqueous samples into a thin layer of organic solvent (dodecane?+?10 % tri-n-octylphosphine oxide) sustained in the pores of a porous hollow fiber. Then, they were back-extracted using a small volume of organic acceptor solution (25 μl; 10 mg/L N-methyl-N-(trimethylsilyl)trifluoroacetamide, as derivatization reagent, in acetonitrile) that was located inside the lumen of the hollow fiber. Under the optimized extraction conditions, enrichment factors of 255 to 280 and limits of detection of 0.1 to 0.2 μg/L (S/N?=?3) with dynamic linear ranges of 1–100 μg/L were obtained for the analytes. The accuracy of the approach was tested by the relative recovery experiments on spiked samples, with results ranging from 93 to 113 %. The method was shown to be rapid, cost-effective, and potentially interesting for screening purposes.