柱净化-分散液液微萃取用于纯化富集油田水域中10种多环芳烃污染物

采用柱净化与分散液液微萃取相结合的样品前处理方法,在去除油田水域中直链烷烃等干扰物的同时,对多环芳烃类污染物(PAHs)进行纯化富集,并利用气相色谱/质谱进行分析。分别考察了柱填料的种类、柱填料与上液量的质量比、柱流速、萃取剂种类及体积、分散剂种类及体积等对萃取效率的影响,最终选择12 g H103大孔树脂为柱填料,以柱填料/样品质量比为12:5上样,在4倍体积/小时(BV/h)柱流速下过柱吸附干扰物,洗脱液加入1.00 mL丙酮(分散剂)和15μL四氯化碳(萃取剂)后进行分散液液微萃取2 min。在最优条件下,PAHs的富集倍数为730~1579,检出限(S/N=3)为1.1~5.3 ng/L,线性范围为0.01~50μg/L,相对标准偏差(n=5)为0.6%~3.4%,回收率为82.6%~104.6%。本方法最大程度地降低了基质中干扰物对分析结果的影响,提高了方法的准确性,操作简单方便,尤其适用于受污染油田水体的快速分析。     

高效液相色谱-串联质谱联用测定人血液中的全氟化合物

采用HPLC-ESI-MS/MS联用技术,建立了分析血样中9种全氟化合物(PFCs)的方法.以13C4标记的PFOS (MPFOS)作为内标物.以C18反相柱为分析柱,甲醇、醋酸铵为梯度洗脱淋洗液,9种分析物包括全氟己烷磺酸(PFHxS)、全氟庚酸(PFHpA)、全氟辛酸 (PFOA)、全氟辛烷磺酸(PFOS)、全氟壬酸(PFNA)、全氟癸酸(PFDA)、全氟十一酸(PFUnDA)、全氟十二酸(PFDoDA)和全氟十四酸(PFTA),在15 min内即可达到良好的分离.在血样前处理中,采用MTBE液-液萃取和固相萃取相结合的方法,进一步净化样品以延长色谱柱寿命;比较了4种固相萃取小柱对全氟化合物的萃取性能,最终选定HLB柱(Waters).本研究还讨论了两种C18反相柱Acclaim 120(50 mm×4.6 mm, 3 μm)和Acclaim120 (250 mm×4.6 mm, 5 μm)(Dionex) 对PFCs的分析性能,在本实验条件下,两种色谱柱具有相似的分离性能及检出限,线性范围在0.1～50 μg/L之间 (r≥0.9957);对于血液样品该方法的检出限在0.03～0.8 μg/L之间.本研究将该方法成功地应用于血样实际样品中全氟化合物的测定,加标回收除PFTA较低外,其它化合物均在74.2%～118.1%之间.     

OPCW第42次环境样品水平考试洗消废水中化武相关化合物的液相色谱-质谱分析

采用液相色谱-质谱技术(LC-MS)对禁止化学武器组织(OPCW)第42次水平考试洗消废水中化武相关化合物进行了详细地分析。首先用高效液相色谱-四极杆飞行时间高分辨质谱(HPLC-Q-TOF MS)从3个洗消废水样品中分辨出空白、控制与模拟真实样品,在模拟真实样品中初步找到3种化武相关化合物;随后采用超高效液相色谱-三重四极杆质谱(UPLC-QQQ MS)对这3种化武相关化合物进一步分析,鉴定出模拟真实样品中的2-羟乙基乙烯基硫醚、二乙烯基砜和1,2-双-(2-羟乙基巯基)乙烷。并对流动相中添加的缓冲剂以及质谱电离碎裂电压与裂解途径进行了优化。所得结果与OPCW提供的配样清单完全一致。该方法可为芥子气洗消产物的分析研究提供参考。     

正相固相萃取/GC-MS对强干扰有机样品中化学毒剂及相关化合物的测定

建立了以硅胶键合氰基柱萃取、正己烷淋洗、混合溶剂分步洗脱,检测强干扰有机液体中化学毒剂及相关化合物的方法.沙林(GB)、梭曼(GD)、甲基膦酸二异丙酯(MPDIP)在0.50 ～50 μg/L范围内,二甲胺基磷酸二乙酯(DEDMP)和维埃克斯(VX)在1.0 ～50 μg/L范围内呈良好的线性关系;对强干扰有机样品中0.5和1.0 mg/L目标化合物的加标回收率均为34% ～100%,且相对标准偏差均小于10%.所建立的方法,不仅消除了强干扰背景对气相色谱-质谱分析的影响,而且避免了目标化合物的丢失和降解,具有较高的实用价值.     

母乳中多种含卤持久性有机污染物的联合检测方法

建立了母乳中多种含卤持久性有机污染物(POPs)的联合检测方法,目标化合物主要包括六溴环十二烷(HBCDs)、多溴联苯醚(PBDEs)、多氯联苯(PCBs)和有机氯农药(OCPs)等.样品的前处理采用液液萃取、凝胶渗透色谱(GPC)净化和固相萃取(SPE)等技术,目标化合物经气相色谱-质谱联用仪(GC-MS)、液相色谱-三重四极杆串联质谱联用仪(LC-MS/MS)和气相色谱-三重四极杆串联质谱联用仪(GC-MS/MS)等进行检测.样品通过GPC除去脂肪,然后经SPE柱进一步净化并进行多组分分离,极大程度地减小了生物样品中复杂基质的干扰,适合样品量相对较小的人体样本中多种超痕量POPs的分析.应用灵敏度高、选择性更好的GC-MS/MS对样品中的PCBs和OCPs等进行分析,进一步降低基质的干扰.方法经过小牛血清加标实验验证,稳定可靠.POPs的加标回收率分别为88.7％～98.8％(PBDEs), 88.5％～92.5％(HBCDs), 67.9％～82.3％(PCBs)和81.7％～116.1％(OCPs),方法检出限分别为0.13～1.8 pg/mL(PBDEs), 0.31～1.2 pg/mL(HBCDs), 0.22～1.4 pg/mL(PCBs)和0.20～1.5 pg/mL(OCPs).采用本方法对潍坊地区20例母乳样品进行分析,结果显示,潍坊市母乳中HBCDs, PBDEs, PCBs、HCHs和DDTs的中值浓度分别为2.86, 7.76, 8.84、140和503 ng/g 脂重,此浓度水平与国内其它地区人群相当.     

涡流色谱技术在生物样品分析中的应用

生物样品的复杂性使其在进行分析测定前必须经过处理。传统的样品前处理方法(如液-液萃取、固相萃取等)耗时长且操作繁琐。涡流色谱作为在线萃取技术,可以实现生物样品直接进样,减少了样品处理步骤,有效富集纯化了分析物,是一种高通量、高选择性的生物样品前处理方法。为此,本文介绍了涡流色谱技术的原理及优势,并总结了不同涡流柱的特点及其在生物样品分析领域中的应用情况。     

一种消毒样品的电喷雾质谱分析

从《禁止化学武器公约》1997年4月正式生效以来,化学核查方法研究不断深入,从鉴定化学战剂原体逐步向降解、消毒等相关化学品方向发展,且扩展到复杂的环境基质样品。为了确保各缔约国履约,对于已被"禁止化学武器组织"(简称OPCW)指定和正在寻求指定的实验室,每年至少要参加一次水平考试,分析公约附表化学品及它们的前体和降解产物,并取得优异的成绩,只有这样,才有资格分析真实样品(从被怀疑的产品或者储藏地点或者是从宣布使用过化学武器的环境中采集的)。本文样品是OPCW组织的第十四次水平考试的"消毒"废液样品D及其空白对照DB,采用液相色谱-电喷雾质谱联用技术(HPLC-ESI-MS)对样品进行定性检测,结合其他分析方法,结果与配样清单完全一致,见表1。     

一维NOESY技术在醇胺混合物分析中的应用

N-甲基二乙醇胺、三乙醇胺、2-二异丙基氨基乙醇分别属于化武相关化合物氮芥气HN2、氮芥气HN3、神经性毒剂Vx前体化合物。采用一维NOESY选择性激发核磁共振技术实现了高背景干扰下对痕量3种醇胺类化合物相关峰的指认和结构的鉴定。方法对三乙醇胺、N-甲基二乙醇胺、2-二异丙基氨基乙醇检测限(S/N3)分别为5,10,10μg/m L。该方法简单、快速、不需要复杂的样品前处理步骤,可以有效排除背景干扰,解决核磁共振氢谱中目标化合物部分峰被掩盖,无法对化合物实施充分鉴定的情况。以第32次禁化武组织的水平考试编号322的有机样品为基质,添加20μg/m L 3种醇胺化合物,使用该方法进行分析,取得了良好的效果。     

电磁感应加热与原子荧光光谱联用测定海产品中的无机汞和有机汞

研制了电磁感应加热装置和磁感应加热柱,并将其应用于有机汞的在线氧化。与冷蒸汽发生-原子荧光光谱法联用,在线测定了海产品中的无机汞和有机汞。样品溶液与K2S2O8在线混合后流经磁感应加热柱,在较低功率(15W)时快速升温将有机汞氧化为无机汞,测定总汞含量;加热柱为室温时,测定无机汞含量,二者之差为有机汞。对各种实验参数和干扰情况进行了详细研究。无机汞的检出限为0.036μg/L;样品分析精密度(RSD)为2.4%(n=11);有机汞的检出限为0.043μg/L,样品分析精密度(RSD)为3.6%(n=11)。     

气相色谱火焰光度法测定水体中9种有机磷酸酯阻燃剂

建立了水体中9种有机磷酸酯阻燃剂(OPFRs)的液液萃取(LLE)/气相色谱-火焰光度(GC-FPD)测定方法。对比研究了液液萃取、固相萃取条件和仪器测定条件。最终选择液液萃取作为样品的提取方法,以二氯甲烷为提取溶剂;有机磷专用柱Rtx-OPPesticides 2作为分析柱,15 min内可实现待测组分的良好分离。在优化条件下,9种OPFRs在1.0~500 ng/m L范围内呈良好的线性关系(r2≥0.998),方法检出限为1.0~2.0 ng/L。在5,100,300 ng/L加标水平下,9种OPFRs空白水样的加标回收率为75.9%~111%;相对标准偏差(RSD)为3.3%~15%。该方法应用于6个实际湖泊地表水样品的检测,OPFRs的检出率为100%,其组分检出总浓度为408~1 532 ng/L,可见湖泊地表水中存在明显的OPFRs污染。     

土壤中64种痕量半挥发性有机污染物的分析方法研究

利用超声提取技术将土壤中的半挥发性有机污染物(SVOC)提取出来, 经旋转蒸发浓缩至一定体积后, 用ODSC18柱净化, 再用氮吹浓缩后, 取1.0 μL注入气相色谱中, 用DB-5 ms柱分离, 用气相色谱质谱仪(GC-MS)进行定性定量分析. 本方法研究土壤中64种半挥发性有机污染物, 其中包括苯系物、苯酚类、苯胺类、硝基芳香烃类、氯代芳烃类、多环芳烃类和酞酸酯类等物质的提取、净化方法以及回收率、精密度和检测限的测定. 该方法回收率为52.5%～105%.     

High resolution capillary GC–MS analysis of low molecular weight organic compounds in municipal wastewater

High resolution capillary gas chromatography–mass spectrometry has been used in combination with various sample preparation methods to analyze a wide range of low molecular weight organic contaminants in municipal wastewaters. Volatile organic compounds were extracted using a purge and trap concentrator connected directly to a wide bore DB-624 capillary column. Because of the high organic load in wastewater samples, this method was preferred to the more sensitive closed loop stripping technique which suffered from competition effects and insufficient adsorbent capacity. Volatile and semi-volatile base/neutral compounds and acids were extracted with dichloromethane at pH 11 and pH 2, respectively, or were recovered using a simultaneous distillation-extraction procedure. Acidic compounds were subsequently derivatized using diazomethane methylation. Both fractions were separated with a 30m DB-5ms capillary column. Specific ionic substances (LAS, NTA, EDTA) were isolated by solid-phase extraction then derivatized with diazomethane (LAS) or acetyl chloride in n-butanol (NTA, EDTA) before GC–MS analysis. This array of techniques enabled the identification of more than 150 organic contaminants in the influent of a municipal wastewater treatment plant in northern suburban Paris. The individual concentrations of these contaminants ranged from < 0.1 μg/l to 5.7 mg/l.     

Design and application of Hadamard-injectors coupled with gas and supercritical fluid sample collection systems in Hadamard transform-gas chromatography/mass spectrometry

A novel Hadamard transform-gas chromatography/mass spectrometry (HT-GC/MS) system equipped with on-line sample collection systems is described. A Hadamard-injector was successfully designed and then coupled with an on-line adsorption/desorption system for detecting volatile organic compounds (VOCs) and a supercritical fluid extraction (SFE) system, respectively, by HT-GC/MS. Six VOCs and three pesticides were used as model compounds. In the former case, an activated-charcoal trap was used to trap VOCs from the indoor air. After 10 L of indoor air had passed through the trap, the condensed components were heated and simultaneously injected into the GC column through the Hadamard-injector, based on Hadamard codes. In a second experiment, a sample of rice was spiked with three types of pesticides and the sample then extracted using a commercially available supercritical fluid extractor. After extraction, the extracted components were transferred to a holding tank and simultaneously injected into the GC column also using the Hadamard-injector. The findings show that, in both cases, the combination of on-line sample collection methods and the use of the Hadamard transform resulted in improved sensitivity and detection. Compared to the single injection used in most GC/MS systems, the signal-to-noise (S/N) ratios were substantially improved after inverse Hadamard transformation of the encoded chromatogram.     

固相萃取净化-液相色谱串联质谱确证茶叶中的6种乙撑双二硫代氨基甲酸盐类农药残留

建立了液相色谱串联质谱法测定茶叶中代森锌、代森锰、代森锰锌、代森钠、代森联、甲基代森锌等6种乙撑双二硫代氨基甲酸盐类农药的确证方法。方法选用碱性乙二胺四乙酸二钠作为提取液,并将难溶盐转化为水溶性钠盐,甲酯化试剂碘甲烷进行衍生化反应,采用亲水-亲脂平衡固相萃取柱(Oasis HLB)净化甲酯化产物,甲醇洗脱,6.5min内衍生物在Sunfire C18色谱柱中完成分离,电喷雾正离子多反应监测模式下监测。茶叶中甲基代森锌的定量下限为20μg/kg,在5～200μg/kg范围内呈良好的线性关系;其它代森盐类化合物的定量下限均为10μg/kg,在2～200μg/kg范围内呈良好的线性关系;在绿茶、红茶和乌龙茶叶中添加不同水平待测物时,平均回收率为79%～99%,相对标准偏差为4.7%～14.6%。经验证该方法可简单、快速、准确地检测多种茶叶中的代森与甲基代森类农药残留。     

Determination of daidzein and genistein in soybean foods by automated on-line in-tube solid-phase microextraction coupled to high-performance liquid chromatography

An automated on-line method for the determination of the isoflavones, daidzein and genistein, was developed using in-tube solid-phase microextraction coupled to high-performance liquid chromatography (in-tube SPME-HPLC). In-tube SPME is a new extraction technique for organic compounds in aqueous samples, in which analytes are extracted from the sample directly into an open tubular capillary by repeated draw/eject cycles of sample solution. Daidzein, genistein and their glucosides tested in this study were clearly separated within 8 min by HPLC using an XDB-C8 column with diode array detection. In order to optimize the extraction of these compounds, several in-tube SPME parameters were examined. The glucosides daidzin and genistin were analyzed as aglycones after hydrolysis because the glucosides were not concentrated by in-tube SPME. The optimum extraction conditions for daidzein and genistein were obtained with 20 draw/eject cycles of 40 microl of sample using a Supel-Q porous layer open tubular capillary column. The extracted compounds were easily desorbed from the capillary by mobile phase flow, and carryover was not observed. Using the in-tube SPME-HPLC method, the calibration curves of these compounds were linear in the range 5-200 ng/ml, with a correlation coefficient above 0.9999 (n = 18), and the detection limits (S/N = 3) were 0.4-0.5 ng/ml. This method was successfully applied to the analysis of soybean foods without interference peaks. The recoveries of aglycones and glucosides spiked into food samples were above 97%.     

Identification of novel synthetic organic compounds with supersonic gas chromatography-mass spectrometry

Several novel synthetic organic compounds were successfully analyzed with a unique type of GC-MS titled Supersonic GC-MS following a failure in their analysis with standard GC-MS. Supersonic GC-MS is based on interfacing GC and MS with a supersonic molecular beam (SMB) and on electron ionization of sample compounds as vibrationally cold molecules while in the SMB, or by cluster chemical ionization. The analyses of novel synthetic organic compounds significantly benefited from the extended range of compounds amenable to analyses with the Supersonic GC-MS. The Supersonic GC-MS enabled the analysis of thermally labile compounds that usually degrade in the GC injector, column and/or ion source. Due to the high carrier gas flow rate at the injector liner and column these compounds eluted without degradation at significantly lower elution temperatures and the use of fly-through EI ion source eliminated any sample degradation at the ion source. The cold EI feature of providing trustworthy enhanced molecular ion (M+), complemented by its optional further confirmation with cluster CI was highly valued by the synthetic organic chemists that were served by the Supersonic GC-MS. Furthermore, the provision of extended mass spectral structural, isomer and isotope information combined with short (a few minutes) GC-MS analysis times also proved beneficial for the analysis of unknown synthetic organic compounds. As a result, the synthetic organic chemists were provided with both qualitative and quantitative data on the composition of their synthetic mixture, and could better follow the path of their synthetic chemistry. Ten cases of such analyses are demonstrated in figures and discussed.     

The Use Of Reverse-Phase Hplc For Soil Amino-N Analysis

Abstract

Soil organic matter was extracted from field soils using mild pretreatment and a Chelex 100 resin bed. The extracts were separated by molecular weight using a Sephadex G-25 gel permeation chromatography column. Reverse-phase high performance liquid chromatography and o-phthalialdehyde precolumn derivatization were used to rapidly determine the primary amino compounds present in the 6 N HCl-soluble fractions. Twenty amino-N compounds were quantitatively identified in the hydrolysates.     

Determination of chlorotoluron, isoproturon and metoxuron in soil by GLC-NPD and confirmation using GLC-MS

Summary The analysis of several phenyl urea herbicides in soil by GLC-NPD, directly or after alkylation, and the confirmation of residues by GLC-ITD is reported. Soil was extracted with methanol, the organic solvent evaporated, the residue dissolved in hexane and then analyzed by gas chromatography on a 3% OV-17 glass packed column. An aliquot of the extract was ethylated overnight with EtI, NaH and Me₂SO as solvent. The mixture was hydrolyzed, the ethylated compounds extracted with hexane and determinated by GLC-NPD on a BP-5 fused silica capillary column. Values obtained with the direct GLC analysis were reproducible and similar to those obtained after ethylation. Recovery of each herbicide was higher than 80% and the limit of detection was 0.01 ppm. These compounds were also analyzed by GLC-ITD. The sensitivity in the SIM mode was near 0.1 ng and the residues can be confirmed with this technique down to 0.01 ppm.     

Three-phase system in solvent bar microextraction: An approach for the sample preparation of ionizable organic compounds prior to liquid chromatography

In this article, a simple new solvent microextraction technique is described for the extraction of ionizable organic compounds. This involves performing simultaneous forward- and back-extraction across an organic film immobilized in the pores of a porous polypropylene hollow fiber. Four chlorophenoxyacetic acid herbicides were chosen as model compounds. The target compounds are extracted from the stirred acidic aqueous sample (adjusted to 0.5 M HCl; donor phase) through a thin film of an organic solvent residing in the pores of a polypropylene hollow fiber; they are then finally extracted into another alkaline aqueous phase (1 M NaOH; acceptor phase). Both ends of the fiber are pressure-sealed. The acceptor phase was analyzed by liquid chromatography (LC). This method gave good enrichment (by a factor of 438-553) of the analytes in 40 min extraction time with reasonably good reproducibility. The analytical potential of the method was demonstrated by applying the method to spiked river water sample.     

On-line coupled superheated water extraction (SWE) and superheated water chromatography (SWC)

Superheated water extraction has been linked directly to a superheated water chromatographic separation so that the process of sample extraction and separation can be achieved without the need for organic solvents at any stage. A model matrix spiked with pharmaceuticals and antioxidants was extracted and the extracted components were collected on a cold polystyrene-divinylbenzene trap. The analytes were then sequentially released by raising the temperature in stages. Each fraction was passed on-line to a polystyrene divinylbenzene analytical column and was eluted with superheated water using a thermal gradient.