Headspace solid‐phase microextraction analysis of volatile compounds from spice essential oils in dry flavourings

The composition of volatile compounds in nine spices was analysed by means of headspace solid‐phase microextraction (HS‐SPME) from dry flavourings of the spice essential oils, to devise an effective method to determine the content of the essential oils. The HS‐SPME was combined with GC‐MS and GC‐FID for identification and quantification of the volatile compounds. The optimisation of the extraction conditions was carried out by response surface methodology. The evaluation of the analytical parameters indicated that the method had a high precision (coefficient of variations lower than 3%), it was linear (response factors were smaller than 5%) and recoveries were higher than 89%. In the ruggedness test, sample quantity and pre‐extraction time were the factors that stood out as the causing of the greater effects on the analytical results.     

Smoke and liquid smoke. Study of an aqueous smoke flavouring from the aromatic plant Thymus vulgaris L

An aqueous smoke flavouring from Thymus vulgaris L was obtained. The qualitative and quantitative composition of its dichloromethane extract was studied by gas chromatography and gas chromatography/mass spectrometry. In addition to the common smoke components such as aldehydes, ketones, diketones, esters, acids, furan and pyran derivatives, alkyl aryl ethers, phenol, guaiacol and syringol derivatives, some terpenic compounds were detected. Differences between this aqueous liquid smoke and others from various kinds of wood are due not only to the absence or presence of some compounds but also to the proportions of the different groups of components present in the mixture. Some aldehydes, esters, guaiacol and its derivatives and terpenic compounds contribute to the overall odour of this liquid smoke more significantly than the ketones, furan and pyran derivatives, acids, phenol and its derivatives and syringol. The yield in smoke components obtained from the pyrolysis of Thymus vulgaris L at 488 °C is of a similar order to that obtained from other woods. © 1999 Society of Chemical Industry     

气相色谱/质谱联用测定纺织品中5种苯酚类化合物

探讨了气相色谱/质谱(GC/MS)联用测定纺织品中4种含氯酚及邻苯基苯酚残留量的方法.样品经甲醇超声提取、浓缩后,用0.1 mol/L的硼砂溶液溶解,再经乙酸酐乙酰化后用正己烷提取,GC/MS测定,外标法定量.在0.05~2.5 mg/L,方法的线性关系良好,相关系数为0.999 0~0.999 5,加标回收率为89%~105%,相对标准偏差为1.46%~5.32%.该方法简便、快速、灵敏度高,完全可满足进出口纺织品中4种含氯酚及邻苯基苯酚残留量检测的要求.     

山楂红酒香气成分的GC/MS分析

利用溶剂萃取法对山楂红酒中的香气成分进行提取,采用气相色谱-质谱(GC/MS)技术对其进行分析.结果表明,在山楂红酒中共分离出73个峰,鉴定出37种化合物;酯类和醇类是山楂红酒中香气组成最复杂的两类化合物,其中主要成分为丁二酸乙酯、苯乙醇、丁二酸二乙酯、甲氧基乙酸乙酯、酒石酸二乙酯、2,3-丁二醇、乳酸乙酯、对羟基苯乙醇、棕榈酸甲酯、4-羟基丁酸内酯.     

固相萃取-气相色谱-质谱联用法测定啤酒大麦中抗蚜威、乙草胺、三唑酮的残留量

研究了气相色谱/质谱法测定啤酒大麦中杀虫剂抗蚜威、除草剂乙草胺、杀菌剂三唑酮3种农药残留的分析检测方法。样品以丙酮作为提取剂,采用超声波清洗器和旋涡混合器混合提取啤酒大麦中的农药残留,经500mg、3mL SupelcleanTML C-18固相萃取柱净化。同时采用SIM的扫描模式,有效地去除了一些杂质的干扰,提高了分析的选择性。该方法的添加回收率在88%～106%,相对偏差小于5.61%,检测限0.010～0.020μg/kg,可相对快捷地检测啤酒大麦中抗蚜威、乙草胺、三唑酮。     

豆渣石油醚萃取物的FT-IR和GC/MS分析

为了解豆渣中小分子物质的赋存形态,本研究用石油醚作溶剂在索式萃取器中对豆渣进行了萃取,并采用傅里叶转换红外光谱仪(FT-IR)和气相色谱/质谱联用仪(GC/MS)对所得石油醚萃取物进行分析,同时用FT-IR对原料豆渣和萃余残渣也进行了分析。结果表明:实验连续萃取5 h,所得石油醚萃取物为淡黄色油状物,萃取率为10.7%;原料和萃余残渣的红外谱图峰形相近,但各吸收峰的吸收强度有所不同,而石油醚萃取物与原料和萃余残渣的红外谱图有明显的差别;石油醚萃取物中共检测到35种GC/MS可识别小分子有机化合物,主要分为烷烃、烯烃、芳香烃、醛、酸、酯及其它类物质7种类别;其中,酯类化合物相对含量为最多,高达61.79%。该研究在开发豆渣的高附加值利用方面具有重要的基础理论意义。     

芳香整理织物中丁香酚的GC/MS测定法

建立了芳香织物中丁香酚的气相色谱 质谱（GC/MS）分析方法。样品经甲醇超声萃取、浓缩、定容后,用DB 5MS柱分离,选择离子（SIM）模式下定量检测。在优化的试验条件下,线性范围为0.01～100 μg/mL,相关系数为0.999 1,定量下限为0.03 mg/kg,加标回收率在89.7%～92.3%,相对标准偏差小于4.7%。该方法灵敏度高、操作简单,可用于芳香织物中芳香剂丁香酚含量的快速检测。     

柱上衍生气相色谱/质谱法测定纺织品中PFOS

全氟辛基磺酸(PFOS)很难通过常规方法从纺织品中分离、检出.采用超声-微波协同萃取仪提取样品中的PFOS,以四丁基氢氧化铵(TBAH)为衍生化试剂,与PFOS形成铵盐,再在柱上进行衍生化反应,形成PFOS丁酯,进而被气相色谱/质谱(GC/MS)联用仪检出.通过探索最佳衍生化反应条件,确立了柱上衍生GC/MS的检测方法,并对实际纺织样品中PFOS进行分离、检测,结果显示样品中的PFOS含量在0.59～11.27 mg/kg之间,能够满足国际法规对纺织品中PFOS的限量检测要求.     

GC/MS分析俄罗斯鲟鱼不同部位脂肪酸组成

通过Folch法提取俄罗斯鲟鱼不同部位总脂,采用GC/MS法对其脂肪酸组成进行分析。通过质谱数据库检索和标准品对照鉴定脂肪酸组成。研究表明,鱼肉、鱼卵、鱼皮、鱼腹中脂肪酸种类及含量类似,多不饱和脂肪酸含量均大于40%,其次为单不饱和脂肪酸(30%左右)和饱和脂肪酸(17%左右),多不饱和脂肪酸以9,12-十八碳二烯酸和DHA为主。鱼肉中总脂含量12.83%,其中,多不饱和脂肪酸为42.37%,EPA+DHA为17.25%;鱼卵总脂含量为14.46%,其中n-3脂肪酸为22.10%;鱼皮含有较高含量的n-6脂肪酸(19.43%);鱼腹总脂含量14.45%,含有较高含量的多不饱和脂肪酸(42.66%)和单不饱和脂肪酸(34.07%),EPA+DHA为17.38%;鱼鳔中未检测到n-3和n-6脂肪酸;鱼肝总脂含量为55.92%,单不饱和脂肪酸含量尤为突出,高达55.81%,以9-十八碳烯酸(49.82%)为主,饱和脂肪酸含量仅为17.24%;椎骨中总脂仅为0.09%。     

尾巨桉木片水抽提物成分的GC/MS分析

采用冷水浸渍法从新鲜尾巨桉木片中提取有效成分,经浓缩、干燥、苯-甲醇溶解后,再用气相色谱/质谱法(GC/MS)联机分析技术,用色谱峰面积归一化法计算各组分的相对含量。共分离出35个峰,结合文献调研,鉴定出12个化合物,占总峰面积的53.67%。主要成分为2,6,10,15,19,23-六甲基-鲨烯(18.04%)、2,4’,5-三甲基二苯甲烷(7.68%)、二十五(碳)烷(5.93%)、2,6,10,14-四甲基-十五烷(5.10%)、十九(碳)烷(4.95%)、2,6,10,14-四甲基-十六烷(3.97%)、5,6-二氢5,6-二甲基苯-邻二氮(杂)萘(2.80%)、7,3’,4’-三甲氧基-槲皮素(1.53%)、6,10,14-三甲基-2-十五烷(1.02%)等。     

GC-MS法测定侧流卷烟烟气中挥发性化合物

采用鱼尾罩和装有剑桥滤片的捕集装置将侧流烟气中的5种挥发性化合物（1,3-丁二烯、异戊二烯、丙烯腈、苯、甲苯）捕集于甲醇溶液中, 采用四极杆GC-MS结合质谱选择性离子扫描模式（SIR）定量测定侧流卷烟烟气中5种挥发性化合物释放量。试验证明,此方法有较好的重复性:对5种挥发性化合物释放量组内测定的RSD≤3.45%,组间测定RSD≤6.27%;具有较高的灵敏度:5种挥发性化合物的检测限均低于0.13 μg /支;较高的准确性:5种挥发性化合物的回收率在93.37%～98.2%之间。      

UPLC-ESI-MS/MS analysis of Sudan dyes and Para Red in food

An analytical method for the simultaneous determination of Sudan dyes (Sudan Red G, Sudan I, Sudan II, Sudan III, Sudan Red 7B and Sudan IV) and Para Red in food by ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-ESI-MS/MS) was developed. Samples were extracted with acetonitrile, and water added into the extract. The supernatant was analysed by UPLC-MS/MS after refrigeration and centrifugation. The sample was separated on an Acquity BEH C₁₈ column, and detected by MS/MS with the multiple reaction monitoring mode. Matrix calibration was used for quantitative testing of the method. The linear matrix calibrations of Sudan dyes and Para Red were 2–50 and 10–250 ng g^?1, respectively, and the regression coefficients were >0.9945. The recoveries were 83.4–112.3% with good coefficients of variation of 2.0–10.8%. The limits of detection were between 0.3 and 1.4 ng g^?1 for the six Sudan dyes, and between 3.7 and 6.0 ng g^?1 for Para Red. The limits of quantification were between 0.9 and 4.8 ng g^?1 for the six Sudan dyes, and between 12.2 and 19.8 ng g^?1 for Para Red.     

地毯有机挥发物的ETC-ATD-GC/MS联用测试法

采用环境测试舱(ETC)、自动热脱附仪(ATD)和气相色谱/质谱(GC/MS)联用技术,建立了地毯中13种挥发性有机物(VOCs)的分析方法。该方法对VOCs单体的最小检出限(LODs)范围为0.008～0.4μg/m~3,方法的加标回收率为90%～106%,相对标准偏差(RSD)小于11%。将该方法用于多种市售地毯的VOCs测试,发现地毯释放VOCs的种类,与地毯底层材料有较大关联,沥青底胶层的方块地毯释放出较多的2-乙基-1-己醇,黄麻背衬地毯和聚酯背衬地毯释放出较多的苯乙烯和4-苯基环己烯,而薄层聚丙烯背衬地毯则释放出较多的直链或支链烷烃。     

Quantitative determination of mycotoxins in urine by LC-MS/MS

Naturally occurring mycotoxins are responsible for a wide array of adverse health effects. The measurement of urinary mycotoxin levels is a useful means of assessing an individual's exposure, but the development of sensitive and accurate analytical methods for detecting mycotoxins and their metabolites in urine samples is challenging. Urinary mycotoxins are present in low pg ml^–1 concentrations, and the chromatographic identification of their metabolites can be obscured by other endogenous metabolites. We developed an analytical method focused on the selection of two appropriate multiple-reaction monitoring transition for unambiguous identification and quantification of carcinogenic aflatoxin M₁ (AFM₁), ochratoxin A (OTA) and fumonisin B₁, B₂ (FB₁, FB₂) in urine samples from a small volunteer group in a pilot study. AFM₁, OTA, FB₁ and FB₂ were concentrated selectively, interfering substances were removed using an immunoaffinity column (IAC), and mycotoxins were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in combination with a stable-isotope standard-dilution assay (SIDA). The method was sensitive enough to measure mycotoxins and their metabolites at pg ml^–1 levels in urine. The combination of LC-MS/MS and SIDA was critical to distinguishing pseudo-OTα interference from genuine OTα. Twelve urine samples contained OTA ranging from 0.013 to 0.093 ng ml^?1 (mean = 0.031 ng ml^?1). AFM₁ were detected in one sample at a 0.002 ng ml^?1 level, while FB₁ and FB₂ were undetectable in all 12 samples. None of the samples in this pilot study contained a detectable level of OTα, despite the presence of OTA, and this may suggest the need for further epidemiological investigation of OTA exposure in the Korean population.     

气相色谱-质谱法测定酱油中氯丙醇类化合物

建立了酱油中两种氯丙醇类化合物检测的气相色谱-质谱分析方法.样品中加入两种稳定性氘代同位素内标,经基质固相分散萃取(MSPD)分步提取、净化,七氟丁酰基咪唑衍生化后进行GC/MS测定.两种氯丙醇化合物的线性范围均为10～1600 ng,检出限为5μg/kg;回收率为99.5%～110%,RSD%为3.8%～6.6%.该方法测定灵敏度高,定性准确,选择性好,稳定性高,适合于样品中多种痕量氯丙醇类化合物的同时测定.     

微波辅助顶空固相微萃取法分析新疆洋葱籽挥发性成分

采用微波辅助萃取与顶空固相微萃取联合的方法萃取新疆洋葱籽挥发性成分,并用气相色谱-质谱联用技术分析对新疆洋葱籽中的挥发性成分进行了鉴定,共分离出50种成分,确认了其中的42种成分,占挥发性成分的95.46%。采用面积归一法确定各成分的相对百分含量,其中主要为萜类化合物及其衍生物。     

UPLC-MS/MS法测定葡萄果实中的高氯酸盐

本研究建立了一种用于定量检测葡萄果实中高氯酸盐的超高效液相色谱-质谱联用(UPLC-MS/MS)分析方法。以葡萄为基质,测定了其中高氯酸盐的含量。前处理最终选择WAX固相萃取柱作为净化柱,分析过程使用100mm×2.1mm的Hypercarb色谱柱,柱温为40℃,流动相采用甲醇-0.2%甲酸水体系,流速为0.3mL.min_-1^,离子源采用ESI源负离子模式,并通过多反应监测(MRM)模式来测定葡萄果实中高氯酸盐含量。经过试验发现当高氯酸盐的浓度处于2-500ng.mL_-1^范围内,浓度与对应的峰面积有着优秀的线性,且回归方程R值超过0.995。此外,这种测试方式的最小检测值是0.3μg.kg_-1^,而最小的测量值则是1.0μg.kg_-1^。在10μg.kg_-1^、20μg.kg_-1^和50μg.kg_-1^{的浓度水平下},高氯酸盐回收率为80.6%~96.8%,相对标准偏差为7.6%~8.5%。用该方法进行预处理更加方便、快速,且检测灵敏度高,可满足葡萄果实中高氯酸盐测定要求。     

液相色谱-串联质谱法测定猪肉中13种磺胺类药物残留

利用液相色谱-电喷雾串联质谱建立猪肉中13种磺胺类药物残留的同时、快速分析方法.猪肉样品中的残留药物用1%乙酸-乙腈均质提取,浓缩后用0.1%甲酸-乙腈定容,并用正己烷液-液分配除脂后,用Kinetex C18色谱柱(100mm×2.1mm,2.6μm)分离,以0.1%甲酸-乙腈作为流动相梯度洗脱,采用电喷雾正离子电离,多反应监测模式检测,基质匹配外标法定量.13种磺胺类药物在1~300μg/kg范围内线性关系良好,定量限均小于10μg/kg.在1、2μg/kg和10μg/kg这3个添加水平下,回收率在60.0%~78.1%之间,相对标准偏差(RSD)在0.24%~8.88%之间.此方法操作简便,灵敏度、准确度、精密度均满足残留分析的要求.     

Differentiation of fresh and frozen/thawed fish, European sea bass (Dicentrarchus labrax), gilthead seabream (Sparus aurata), cod (Gadus morhua) and salmon (Salmo salar), using volatile compounds by SPME/GC/MS

BACKGROUND: A simple method based on solid phase microextraction/gas chromatography/mass spectrometry (SPME/GC/MS) was applied for studying the volatile profiles of whole fish samples of European sea bass (Dicentrarchus labrax) and gilthead seabream (Sparus aurata) and fillets of cod (Gadus morhua) and salmon (Salmo salar) during frozen storage in order to be able to differentiate a fresh product from one that has been frozen. Analysis of volatile compounds was performed on these two product types, fresh and after freezing/thawing following storage at ? 20 °C for 30 and 90 days. RESULTS: More than a hundred volatile compounds were found by SPME/GC/MS. Statistical processing by principal component analysis and ascending hierarchical classification was used to classify the samples into categories and verify the possibility of separating fresh samples from those that had been frozen and thawed. The compounds to be used as differentiators were identified. Four compounds were common to all species: dimethyl sulfide, 3‐methylbutanal, ethyl acetate and 2‐methylbutanal. Not only were they found in larger quantities after thawing but they also increased with the duration of storage at ? 20 °C. CONCLUSION: These four compounds can therefore be considered as potential markers of differentiation between a fresh product and one that has been frozen. Copyright © 2012 Society of Chemical Industry