气相色谱-质谱法测定大鼠血浆和肝匀浆中丙二醛含量

提出了用气相色谱-质谱法测定大鼠血浆和肝匀浆中丙二醛(MDA)含量。样品与1.0mol.L-1氢氧化钠溶液在60℃水浴中反应60min产生丙二醛,加入五氟苯肼(PFPH)衍生化试剂进行衍生化,所得衍生化产物通过HP-5MS色谱柱分离,采用电子轰击离子源选择离子监测模式进行质谱测定。丙二醛-五氟苯肼衍生物(MDA-PFPH)定量离子为m/z 234,内标物甲基丙二醛衍生物(Me-MDA-PFPH)定量离子为m/z248。血浆和肝匀浆中丙二醛的线性范围分别为1.0～50.0μmol.L-1和50～500μmol.L-1,加标回收率分别在94.6%～103%和93.2～106%之间。方法的日内、日间相对标准偏差(n=6)均小于5%。     

衍生化-离子阱气相色谱质谱联用检测乳粉中三聚氰胺时不同质谱检测方法研究

利用N,O-双三甲基硅基三氟乙酰胺(BSTFA)和三甲基氯硅烷(TMCS)衍生化试剂对乳粉中三聚氰胺进行衍生化处理,利用离子阱气相色谱质谱联用仪,建立了全扫描、选择离子监测、二级质谱3种测定三聚氰胺的质谱方法.选择离子监测以三聚氰胺衍生物的特征离子m/z342,327,171,99为定性离子,以m/z327为定量离子;全扫描法二级质谱特征峰为定性依据,以特征离子m/z327为定量离子;二级质谱法以衍生物二级质谱m/z285,171,213为定性离子,以m/z 285为定量离子.3种方法的线性范围为0.05～2.0 mg/L,线性相关系数分别为0.9986、0.9990、0.9988;检测限分别为0.005、0.002、0.003 mg/kg,RSD分别为6.3%、5.7%、6.1%(n=6),方法的回收率为84%～105%.3种不同质谱检测方法应用到乳粉的检测中效果良好,均能够满足乳粉中三聚氰胺的检测要求.     

气相色谱-质谱法测定鸡肉组织中残留的氯羟吡啶

建立了气相色谱-质谱(GC-MS)测定鸡肉组织中氯羟吡啶残留的确证方法。采用乙腈提取鸡肉组织中的待测物,经碱性氧化铝层析柱净化,Sylon BFT衍生剂衍生后,采用选择离子监测(SIM)模式检测。对氯羟吡啶三甲基硅烷化衍生物的电子轰击（EI）质谱碎片进行解析,选择m/z 212,214,248和263等4个特征离子作为定性离子,其中m/z 248为定量离子。同时还考察了检测过程中的基质效应。氯羟吡啶衍生物的响应与其质量浓度在5.0～500 μg/L范围内呈良好的线性关系,相关系数大于0.998;以3倍信噪比(S/N)计算方法的检出限达0.5 μg/kg;在5,10和20 μg/kg添加水平下鸡肉组织中待测物的平均回收率分别为77.0%,84.5%及89.4%,相对标准偏差小于6.9%。结果表明,该方法简单、灵敏、可靠,适用于鸡肉组织中氯羟吡啶残留的分析确证。     

硝西泮、氯硝西泮甲基衍生物的气相色谱-质谱分析

对硝西泮和氯硝西泮的衍生化条件、色谱及质谱行为进行了研究,确立了猪肉中硝西泮、氯硝西泮残留的GC-MS检测方法.应用5因素4水平的正交试验,最终确定衍生化条件为反应温度60℃、反应时间30 min、丙酮用量0.5 mL、衍生化试剂20μL、催化剂无水碳酸钾20mg,在此条件下可生成较完全的甲基衍生物.衍生物具有较好的气相色谱和电子轰击质谱行为.硝西泮衍生物的分子离子峰为m/z 295,基峰离子为m/z 267,主要碎片离子分别为m/z 206、220、248、294;氯硝西泮衍生物的分子离子峰为m/z 329,基峰离子为m/z 328,主要碎片离子分别为m/z205、220、248、266、294、331,并对这些离子的产生进行了解析.这些离子均具有较强的相对丰度,可作为其微量检测的多离子选择定性和确证,而基峰离子可用于单离子选择定量.用乙腈提取药物,C18固相萃取柱净化,GC-MS分析.本方法采用外标法定量,两种药物的标准曲线线性回归系数均在0.99以上,线性范围20～500 μg/L,回收率80%左右,相对标准偏差6.9%～14.9%,检出限16.7 μg/kg.     

硅烷化法在卤代物质谱分析中的新应用

利用气相色谱-质谱法对一系列脂肪卤化物及芳香卤化物的三甲基硅烷基(TMS)衍生物在电子轰击离子源(EI)下的裂解行为进行了研究。质谱分析结果表明:有机卤化物的TMS衍生物在发生碎裂反应的过程中均生成元素组成符合[(CH_3)_2XSi]~+(X=F、Cl、Br、I)的特征骨架重排产物离子,即m/z 77、m/z 93、m/z 137、m/z 185。此外,卤素原子取代位置的改变对重排产物离子峰的强度、类型也产生了显著影响。通过对这一类重排产物离子的研究,可快速、有效的鉴别卤代物的位置异构体,以及逆向分析有机分子的元素组成。此硅烷化的分析手段不仅可为有机卤代化合物结构的解析提供新的思路,同时也可拓展硅烷类衍生化试剂在有机质谱分析领域中的应用。     

气相色谱-质谱法测定电子产品中四溴双酚A

建立了超声提取-硅烷化气相色谱-质谱测定电子产品中四溴双酚A的方法.样品用正己烷/丙酮作提取剂,浸泡后超声提取,经N,O-双三甲基硅烷三氟乙酰胺(BSTFA)+1%三甲基氯硅烷(TMCS)衍生化,利用气相色谱-质谱仪进行定性定量分析.讨论了浸泡时间对提取效率的影响,优化衍生温度和衍生时间.结果表明:标样衍生后在0.4～...     

硅烷化衍生-气相色谱-质谱联用法测定烟草中的游离氨基酸

建立了氨基酸硅烷化衍生-气相色谱-质谱联用法测定烟草中18种游离氨基酸的分析方法。烟叶样品用75%乙醇萃取,萃取液真空干燥后在75℃下加入N-叔丁基二甲基甲硅烷基-N-甲基三氟乙酰胺(MTBSTFA)衍生试剂进行硅烷化衍生反应30 min后在选择离子监测(SIM)模式下进行GC/MS分析,采用内标法定量。结果表明:18种氨基酸的定量标准曲线线性良好,R2为0.9990~0.9999,方法的加标回收率为97.4%~114.1%,相对标准偏差为0.17%~3.4%。该方法前处理操作快速简便、检测灵敏度高,适用于烟草中游离氨基酸含量的定量分析。     

动物组织中己烯雌酚残留的基体固相扩散-气相色谱-质谱分析方法研究

采用基体固相扩散和固相萃取结合的方法提取并净化动物肝脏组织中残留的己烯雌酚，用N-甲基，N-三甲基硅烷三氟乙酰胺衍生化，毛细管气相色谱-质谱联用(选择离子模式，选择离子为：383、397、412、413)对衍生物检测分析，确立了对动物肝脏组织中己烯雌酚定性、定量分析的方法。该法检出限低于1μg/kg；不同DES加入量的回收率为81．6％-100．9％；相对标准偏差8．7％-13．2％。     

气相色谱-质谱联用法同时测定乳及乳制品中的三聚氰胺及肌酐

建立了同时测定乳制品中三聚氰胺及肌酐的气相色谱-质谱联用方法。样品经1%三氯乙酸溶液萃取,混合型阳离子交换固相萃取净化,提取液用氮气吹干后加入N,O-双(三甲基硅基)三氟乙酰胺-三甲基氯硅烷(BSTFA-TMCS)硅烷化试剂,于75 ℃下衍生60 min,最后采用选择离子模式下的气相色谱-质谱测定。三聚氰胺和肌酐的定量限分别为0.10 mg/kg和0.20 mg/kg;在0.1～50 mg/L范围内的线性相关系数均大于0.99。实际样品中,肌酐在10～100 mg/kg和三聚氰胺在0.1～5.0 mg/kg添加范围内的回收率分别为80.7%～116.8%和77.6%～107.5%,相对标准偏差分别小于9.4%和8.5%。该方法能有效除去干扰,灵敏度高,回收率较好,可用于乳制品中三聚氰胺和肌酐的同时测定。     

气相色谱/负化学源质谱法测定蜂蜜中氯霉素的残留量

建立气相色谱／负化学源质谱(GC／NCIMS)测定蜂蜜中氯霉素残留量的方法。蜂蜜中残留的氯霉素经液-液萃取、固相萃取提取、净化和硅烷化衍生后,进样分析。负化学源质谱采用选择离子模式进行检测,特征离子为m／z=466,468,外标法定量。结果表明,样品中氯霉素浓度为1.0-20μg·kg-1时,工作曲线的线性良好(r=0.9989),回收率为71％-93％,检出限为0.5μg·kg-1。     

Measurement of imidazoleacetic acid in urine by gas chromatography-mass spectrometry

Imidazoleacetic acid (IAA), a histamine and histidine metabolite, was quantified in human urine by gas chromatography-mass spectrometry (GC-MS). The acid was separated by ion-exchange chromatography, derivatized as the n-butyl ester with boron trifluoride-butanol and the derivative extracted with chloroform. GC-MS analysis was carried out by selected-ion monitoring of ions m/z 81 and m/z 83 corresponding, respectively, to IAA and [15N,15N']IAA used as internal standard. The mean IAA content in urine was about 8.02 nmol/mg of creatinine. The specificity of measurement was rigorously established by GC retention time, peak shape, ion abundance ratios, and recovery experiments. The method is capable of quantifying IAA in 0.05 ml of urine and in amounts as low as 0.20 nmol.     

气相色谱-质谱法测定水体中三氟乙酸

用多级浓缩的预处理富集水中微量的三氟乙酸,再将富集的三氟乙酸通过甲酯衍生化生成适合顶空进样的三氟乙酸甲酯,以气相色谱-质谱法对水体中三氟乙酸进行测定。试验对顶空进样的条件进行了优化,采用全扫描模式进行定性分析,选择离子扫描模式,以质荷比59,69的特征离子进行定量检测。检出限(3s)为1μg.L-1,对空白溶液进行加标回收试验,回收率在64.3%～68.1%之间,相对标准偏差(n=6)在5.62%～5.78%之间。     

Rapid and Sensitive Analysis of Diclofenac in Human Plasma by GC/SIM/MS

ABSTRACT

An analytical method for the determination of diclofenac with tolfenamic acid as the internal standard was developed and validated in human plasma by capillary gas chromatography-mass spectrometry (GC/MS). After the addition of the internal standard, the compounds were extracted from plasma at acidic pH into diethylether, which was then evaporated to dryness. The compounds were derivatized with pentafluoropropionic anhydride (PFPA) and a mixture (1000:2:3, v/w/w) of N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA), ammonium iodide (NH₄I), and dithioerythritol (DTE). They were determined by GC/MS at m/z 349 (a molecular ion) for diclofenac and m/z 270 (a base ion) for tolfenamic acid. The recovery of this procedure was 97.8%, and the linearity for calibration was 0.9907 as the coefficient factor. The detection and quantitation limits were 0.1 and 0.5 ng/mL, respectively.     

Detection of oxidative stress. Interest of GC-MS for malondialdehyde and formaldehyde monitoring

Ischemia-reperfusion syndrome is a condition where the role of oxygen free radicals is important. Malondialdehyde (MDA) and formaldehyde (FA), products of lipid peroxidation, are the presumptive markers for the development of oxidative stress in tissues and plasmas. A GC-MS method for the determination of MDA and FA in rat brain extract is described. Rat brains were homogenized with deionized water. The homogenates were derivatized with 2,4-dinitrophenylhydrazone (DNPH) to obtain hydrazines derivatives of MDA and FA. The hydrazine derivatives were analyzed by GC-MS and quantitation was by single ion monitoring (SIM). The retention times of FA and MDA were, respectively, 13.75 and 14.20 min, and for SIM quantitation, ion at m/z 210 for FA, and m/z 158 for MDA were used. The results showed that it is possible to estimate the products of lipid peroxidation in brain and to monitor the oxidative stress developed during the ischemia-reperfusion syndrome compared to the normal values.     

Isatin (indole-2,3-dione) in urine and tissues. Detection and determination by gas chromatography-mass spectrometry

A simple procedure based upon capillary column gas chromatography-mass spectrometry (GC-MS) is described for the detection and determination of isatin (indole-2,3-dione) in body fluids and tissues. After addition of 5-methylisatin as internal standard to urine or tissue homogenates, organic extracts are dried and derivatized successively with hydroxylamine hydrochloride and the reagent N-tert.-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA). The tert.-butyldimethylsilyl derivatives obtained show good GC-MS properties and allow quantification by selected-ion monitoring of m/z 333 (isatin) and m/z 347 (internal standard). Adult and newborn human urine output values lie in the ranges 0.4-3.2 mg/mmol of creatinine (5-30 mg per 24 h) and 0.002-0.518 mg/mmol of creatinine, respectively. There is a discontinuous regional distribution in rat tissues. The GC-MS properties of a number of derivatives formed by successive reaction of isatin with hydroxylamine hydrochloride (or methoxyaminehydrochloride or ethoxyamine hydrochloride) and MTBSTFA, bis(trimethylsiyl)trifluoroacetamide, pentafluoropropionic anhydride or pentafluorobenzyl bromide are also described.     

Trimethylsilyl-O-methyloxime derivatives for the measurement of [6,6-2H2]-D-glucose-enriched plasma samples by gas chromatography-mass spectrometry.

A new method for the determination of the enrichment of [6,6-2H2]-D-glucose in human plasma by gas chromatography-mass spectrometry (GC-MS) is described. (2,3,4,5,6)-Pentakis-O-trimethylsilyl-O-methyloxime-D-glucose is used as a derivative for the GC measurement. Using GC-MS with electron-impact ionization, the enrichment is measured in the single-ion monitoring mode observing the masses m/z 319 and 321. In contrast to other methods the use of this glucose derivative reduced the amount of plasma needed from 200 to 10 microliters and no chemical ionization equipment is needed for the mass spectrometer.     

气相色谱-质谱法测定富硒酵母中的硒蛋氨酸

建立了气相色谱-质谱（GC-MS）测定富硒酵母中硒蛋氨酸含量的方法。比较了3种从样品中提取硒蛋氨酸方法的效果。样品在三羟甲基氨基甲烷（Tris）缓冲液中酶解24 h后,以丁醇及三氟乙酸酐为衍生化试剂对硒蛋氨酸进行衍生化,采用选择离子模式对衍生物进行GC-MS测定。硒蛋氨酸的回收率为98.5%~103.7%,相对标准偏差为0.9%~2.4%,检出限为0.5 mg/L（S/N=3）。对实际样品进行测定,得到样品中硒蛋氨酸的含量结果。该法简便快速,准确可靠,灵敏度高。     

气相色谱-质谱法测定纺织助剂中的有机锡

建立了纺织助剂中二丁基锡(dibutyltin, DBT)、三丁基锡(tributyltin, TBT)及三苯基锡(triphenyltin, TPhT)化合物的气相色谱-质谱联用(gas chromatography-mass spectrometry, GC-MS)检测方法。在乙酸-乙酸钠缓冲溶液(pH 4.0)中,用正己烷超声萃取(对疏水性样品)或振荡萃取(对亲水性样品)试样中的有机锡,然后以四乙基硼化钠的四氢呋喃溶液为衍生化试剂进行衍生化,用GC-MS测定,依据保留时间和选择离子定性,外标法定量。实验结果表明,在0.1～8.0 mg/L(对于DBT和TBT)或0.1～4.0 mg/L(对于TPhT)的范围内,有机锡化合物的浓度（以有机锡阳离子计）与其衍生物峰面积呈良好的线性关系,线性相关系数(r2)为0.9994～0.9998,检出限为0.003～0.005 mg/L; 4种聚氨酯类助剂基质中3种有机锡化合物的平均加标回收率为92.6%～108.0%,相对标准偏差为2.5%～10.2%。该方法的技术指标满足纺织助剂中有机锡化合物的测定要求。     

气相色谱-质谱法测定乳制品中光引发剂异丙基硫杂蒽酮的残留量

建立了采用气相色谱（GC）-质谱(MS)检测由包装材料迁移到乳制品中的光引发剂异丙基硫杂蒽酮残留量的方法。使用氘代蒽为内标,样品经Carrez试剂除蛋白质后用丙酮-正己烷(体积比为1∶1)提取,上层提取液用氟罗里硅土固相萃取小柱净化。采用单四极杆质谱进行样品筛选和定量,选取的监测离子为m/z 184,m/z 224,m/z 239,m/z 254(异丙基硫杂蒽酮)和m/z 80,m/z 94,m/z 188,m/z 160(氘代蒽)。疑似样品采用离子阱串联质谱法进行确证,选取的母离子和子离子分别为m/z 254,m/z 239(异丙基硫杂蒽酮)和m/z 188,m/z 160(氘代蒽)。本方法的测定低限(LOQ)分别为7.0 μg/L(GC-MS)和5.0 μg/L(GC-MS/MS),回收率为74.9%~89.6%。采用该方法对11种不同类型的乳制品进行了检测,发现了两例阳性样品。     

气相色谱-质谱法测定水中痕量的四乙基铅

建立了气相色谱-质谱(GC-MS)测定水中痕量四乙基铅的分析方法。用正己烷萃取水样中的四乙基铅,萃取液浓缩后加入同位素内标萘-d8,采用GC-MS选择离子方式(SIM)进行检测,在200 mL水样中四乙基铅的检出限可达0.04 μg/L;添加回收率为92.2%～103%,准确度好;平行5次测定的相对标准差为4.4%～13.3%。结果表明: 方法简便、快速、准确、实用,可用于水中痕量四乙基铅的测定。