高效液相色谱-质谱法测定橄榄油中β-谷甾醇的含量

采用皂化法进行样品前处理,高效液相色谱柱进行分离,采用大气压化学电离源(APCI),以正离子检测方式进行质谱分析,外标法定量,建立了液相色谱-质谱(LC-MS)法检测橄榄油中β-谷甾醇含量的方法。实验结果表明,β-谷甾醇质量浓度在5.00~100 mg/L范围内与色谱峰面积呈良好的线性关系,相关系数R2=0.9999,检出限为1.00 mg/kg。在2个添加水平下,样品的加标回收率为90.1%~96.0%,相对标准偏差为2.1%~4.1%(n=6)。该方法的建立,为橄榄油中β-谷甾醇的检测提供了一种前处理简便、选择性好、灵敏度高的检测方法。     

液质联用法检测降血糖类保健食品中非法添加的13种化学药物

建立同时检测保健食品中非法添加的13 种化学降糖药物的液相色谱串联质谱分析方法并用于实际检测。保健食品样品经甲醇超声提取后,以色谱柱(2.1 mm×150 mm,5 μm)进行分离,甲醇和10 mmol/L乙酸铵水溶液(含0.1 %甲酸)为流动相梯度洗脱;采用电喷雾电离源正离子(electrospray ionization positive,ESI+),多反应监测(multiple reaction monitoring,MRM)模式进行检测。13 种化学降糖药物线性相关系数均大于0.999,定量限(limits of quantitation,LOQ)为45.7 μg/kg^79.6 μg/kg,回收率为78.6 %~112.1 %,相对标准偏差(relative standard deviations,RSD)为 0.6 %~3.5 %。从11种样品中检测出5种样品含非法添加化学药物,且均为复合添加。2种样品添加二甲双胍,5种样品添加苯乙双胍,2种样品添加罗格列酮,1种样品添加甲苯磺丁脲,1种样品添加吡格列酮,5种样品添加格列本脲。     

反相高效液相色谱-串联质谱法测定植物油中生育酚的含量

采用C18反相色谱柱分离,大气压化学电离源(APCI)离子化,三重串联四级杆质谱测定,通过优化质谱参数、样品前处理条件,建立了植物油中α-、β-、γ-、δ-生育酚的反相高效液相色谱-串联质谱定量检测方法。结果表明,该方法检出限为0.05~0.10 mg/kg,线性范围0.025~50.0 mg/L,加标回收率在80.4%~97.4%之间,RSD小于10%。为植物油中生育酚的检测提供了一种更为灵敏、更易于推广的新方法。     

气相色谱-质谱法测定曼陀罗药酒中莨菪碱的含量

本试验采用气相色谱-质谱法测定曼陀罗药酒中莨菪碱的含量,样品经浓度为2mol/L的盐酸溶液提取后超声处理,上清液以浓氨水调至pH=9后用三氯甲烷液-液萃取后氮吹至近干,残渣用三氯甲烷溶解,然后用气质联用仪分离测定;采用电子电离源(EI)模式电离,单离子选择(SIR)监测方式检测。结果显示,该方法的线性范围为100~1000μg/L,线性回归方程为Y=85.6X-4.638,r=0.999,样品最低定量浓度(LOQ)为0.01mg/kg,在0.05~5.0mg/kg添加水平下回收率为82%~94%,相对标准偏差(RSD)为4.9%~7.4%。故得出结论,本方法准确度高且重复性好,能够用于曼陀罗药酒中莨菪碱含量的快速测定。     

QuEChERS-超高效液相色谱-大气压化学电离-串联质谱法测定多种动物源性食品中的地塞米松残留

目的建立QuEChERS-超高效液相色谱-串联质谱法测定多种动物源性食品中地塞米松残留量的分析方法。方法样品经含1%甲酸的乙腈提取, QuEChERS方法净化后,以乙腈-0.1%甲酸水溶液为流动相,经PhenomenexKinetexF5色谱柱(100mm×3.0mm,2.6μm)分离,采用大气压化学电离源(atmosphericpressure chemicalionization,APCI),正、负模式同时扫描的离子化模式,多反应监测(MRM)模式采集,外标法定量。结果地塞米松在0.5～100 ng/mL浓度范围内线性良好,相关系数(r)为0.99946,检出限为0.10μg/kg;在3个加标水平下,平均回收率为73.2%～95.9%,精密度(n=6)为4.1%～10.7%。结论该方法简单、快速、稳定性高、重现性好,可满足多种动物源性食品中地塞米松残留量的检测。     

大气压气相色谱电离源-串联质谱法测定蔬菜中23种农药残留

目的 建立蔬菜中23种农药的大气压气相色谱电离源-串联质谱检测方法。方法 采用丙酮提取蔬菜样品中的目标农药,多壁碳纳米管为净化材料,经DB-5MS色谱柱(30 m×0.25 mm,0.25 μm)分离,结合大气压气相色谱电离源技术,正离子多反应监测(MRM)模式进行检测,外标标准曲线法定量。结果 23种农药在0.01～20 μg/L范围内线性良好,相关系数(R²)均大于0.99,在蔬菜基质中23种农药的方法检出限和定量限分别为0.02～0.40和0.05～1.25 μg/kg,回收率为66.7%～110.7%,相对标准偏差(RSD)≤14.8%。结论 本方法具有良好的灵敏度、重现性和特异性,适用于蔬菜中多种农药残留的快速检测。     

QuEChERS-气相色谱-质谱法测定土豆中109种农药残留

建立土豆中109种农药残留的气相色谱-质谱(GC-MS)检测方法。方法 土豆样品以乙腈提取后,经N-丙基乙二胺(PSA)分散固相萃取净化(d-SPE),采用电子轰击电离源(EI)和负化学电离源(NCI)两种电离模式进行GC-MS测定。结果 各农药的定量限在0.001～0.010 mg/kg之间,对空白土豆样品的平均加标回收率为72.7%～118.7%,RSD在1.1%～17.3%之间。在EI模式下,土豆基质对绝大多数农药具有明显的基质效应,因此采用基质匹配标准曲线进行定量分析。应用此方法对欧盟农药残留参比实验室组织的国际比对考核的土豆样品进行定性筛查和定量测定,共检测出13种农药残留,含量范围在0.002～1.669 mg/kg之间,所提交的测定结果的Z评分值在-1.00～1.00之间。结论 本方法简便快速、准确、灵敏度高,适用于农产品中农药多残留的分析。     

高效液相色谱-串联质谱法测定桑叶茶中1-脱氧野尻霉素的含量

目的 建立了桑叶茶中1-脱氧野尻霉素(1-deoxynojirimycin,1-DNJ)含量的高效液相色谱-串联质谱测定方法。方法 样品经70%甲醇水超声提取,用xbridge amide柱(2.1 mm×100 mm, 3.5 μm)分离, 以含0.1%(V/V)甲酸溶液和乙腈作为流动相进行梯度洗脱, 采用大气压化学电离(Atmosphere Pressure Chemical Ionization, APCI)和多离子检测模式(multiple reaction monitoring, MRM)进行检测,外标法定量。方法 目标物在0.01~0.2mg/L范围内线性相关系数大于0.99; 1-脱氧野尻霉素的定量限为5mg/kg;在5~50mg/kg浓度范围内加标回收试验, 平均回收率在94.2%~98.7%, 相对标准偏差为3.2%~4.7%。结论 该方法具有分析速度快、操作简便等优点,可用于桑叶茶中1-脱氧野尻霉素的含量测定。     

高效液相色谱-串联质谱法测定保健食品中的番茄红素

建立保健食品中番茄红素的液相色谱-串联质谱测定方法。样品经氢氧化钾溶液乙醇皂化,去除脂肪后用质量浓度为1g/100mL的2,6-二叔丁基-4-甲基苯酚(BHT)石油醚溶液提取,提取液经中性氧化铝固相萃取柱净化,采用液相色谱-质谱联用技术-大气压化学电离源多反应监测模式检测,外标法定量。方法的检出限和定量限分别为10μg/kg和100μg/kg,在50～5000μg/kg添加水平范围内,平均回收率为88.0%～103.1%,相对标准偏差低于15%。本方法灵敏,为保健食品中番茄红素的定量检测和确证提供了新的手段。     

QuEChERS-液相色谱-串联质谱法测定茶叶中的丁醚脲

目的:建立茶叶中丁醚脲农药残留检测的液相色谱-串联质谱方法。方法:茶叶样品用乙腈提取后所得提取液经过Qu ECh ERS法净化除去杂质。采用乙腈-水(含0.1%甲酸)流动相体系进行洗脱,C_(18)色谱柱进行色谱分离,电喷雾正离子模式电离,多级反应模式监测,外标法定量。结果:采用GB/T 23205—2008《茶叶中448种农药及相关化学品残留量的测定液相色谱-串联质谱法》检测丁醚脲时回收率低的主要原因是其在前处理过程中发生了分解。采用本实验建立的方法,丁醚脲在1.0~500μg/L质量浓度范围内线性良好(r=0.999 9),定量限为0.01 mg/kg。在0.010、1.0、5.0 mg/kg三个添加量水平的平均加标回收率为83.3%~99.4%,相对标准偏差在1.87%~6.30%之间。结论:本方法操作简便,耗时较短,有效避免了前处理过程中丁醚脲分解对检测结果的影响,适用于茶叶中丁醚脲残留的定性及定量分析。     

亚精胺对小鼠骨骼肌自由基代谢影响及抗疲劳的效果研究

目的：研究亚精胺（spermidine,SPD）对骨骼肌自由基代谢的影响以及抗疲劳作用。方法：实验分为生理盐水组、SPD低剂量组（0.5 mmol/（kg·d））、中剂量组（1.0 mmol/（kg·d））、高剂量组（1.5 mmol/（kg·d））以及西洋参口服液阳性对照组（总皂苷30 mg/（kg·d））,每周灌胃6 d共30 d,每次灌胃前称量小鼠体质量调整灌胃溶液量,灌胃期间进行每天45 min无负重游泳训练。各组随机选取10 只小鼠测试力竭游泳时间;各组剩余10 只负重游泳30 min,休息30 min后取材,检测血清肌酸激酶（creatine kinase,CK）、骨骼肌谷胱甘肽-过氧化物酶（glutathione peroxidase,GSH-Px）、总超氧化物歧化酶（total-superoxide dismutase,T-SOD）、琥珀酸脱氢酶（succinate dehydrogenase,SDH）活性和骨骼肌丙二醛（malondialdehyde,MDA）含量。结果：与生理盐水组比较,SPD能显著延长小鼠力竭游泳时间（P＜0.05）;低、中剂量组骨骼肌中GSH-Px、T-SOD、SDH酶活性显著提高（P＜0.05）,MDA含量显著降低（P＜0.05）;SPD组与西洋参组比较,低、中剂量抗疲劳效果有非常显著性（P＜0.05）差异,高剂量抗疲劳效果略优（P＞0.05）。结论：0.5～1.0 mmol/（kg·d） SPD可以增加抗氧化酶的活性,减少自由基的积累,提高骨骼肌细胞膜代谢能力和抗损伤能力,显著推迟小鼠疲劳发生。     

气相色谱法检测饮料中二羰基化合物

建立同时在线检测丙酮醛和乙二醛的气相色谱方法。确定检测二羰基化合物的最佳条件为：以丁二酮为内标,以邻苯二胺为衍生化试剂,邻苯二胺的用量67 倍于二羰基化合物、衍生化时间10 min、萃取溶剂二氯甲烷、超声时间15 min、萃取2 次、柱箱初始温度40 ℃、程序升温5 ℃/min,色谱柱载气流量2.0 mL/min,分流比1∶1。丙酮醛和乙二醛的定量限（RSN≈10）分别为0.06 mg/L和0.08 mg/L,检出限（RSN≈ 3）分别为0.02 mg/L和0.03 mg/L,方法灵敏度高。     

Use of poly(ether-block-amide) in pervaporation coupling with a fermentor to enhance butanol production in the cultivation of Clostridium acetobutylicum

The toxicity of the end-products of acetone-butanol-ethanol (ABE) process, mainly butanol, is recognized as the major problem contributing to the low productivity of butanol. The pervaporation technique was regarded as one of the ways to efficiently remove organic components. The results of pervaporation performance of poly(ether-block-amide) (PEBA) and polydimethylsiloxane (PDMS) membrane in a model solution indicated that PEBA membrane owned a higher butanol permeation flux of 9.975 gm(-2)h(-1) as opposed to 3.911 gm(-2)h(-1) using a PDMS membrane. Moreover, a higher temperature would result in a higher permeation flux, but has a lower separation factor (α) obtained, while using PEBA membrane. The batch fermentor operation connected to the pervaporation with PEBA membrane created 43% and 34% of increase in the butanol productivity and in the yield as compared to that of the simple batch. The fed-batch fermentation mode by glucose feeding combined with PEBA pervaporation lasting for 24h could achieve 39% increase of butanol productivity as compared to a simple batch. Conclusively, the pervaporation with PEBA membrane coupling with fermentor was presumed to be capable of enhancing butanol production in ABE fermentation, which might have the potential applied in the commercialized ABE fermentation process.     

PVPP对啤酒中多酚类物质和蛋白质的吸附作用比较

为了比较PVPP对啤酒中多酚类物质和蛋白质的吸附作用,以牛血清蛋白为例,采用PVPP分别处理原啤酒、牛血清蛋白(BSA)溶液以及BSA原啤酒混合溶液。实验发现,在相同条件下,尽管PVPP对牛血清蛋白具有较强的吸附作用,但对啤酒中多酚类物质的吸附作用更强;而在BSA原啤酒混合溶液中,多酚类物质被吸附量远远大于牛血清蛋白。结果表明,多酚类物质通过竞争吸附占据PVPP的吸附活性点。     

Oxidation mechanisms occurring in wines

The present review aims to show the state of the art on the oxidation mechanisms occurring in wines, as well as the methods to monitor, classify and diagnose wine oxidation. Wine oxidation can be divided in enzymatic oxidation and non-enzymatic oxidation. Enzymatic oxidation almost entirely occurs in grape must and is largely correlated with the content of hydroxycinnamates, such as caffeoyltartaric acid and para-coumaroyltartaric acid, and flavan-3-ols. Non-enzymatic oxidation, also called chemical oxidation of wine, prevails in fermented wine and begin by the oxidation of polyphenols containing a catechol or a galloyl group. These phenolic reactions, both enzymatic and non-enzymatic, result in by-products named quinones. However, in non-enzymatic oxidation, oxygen does not react directly with phenolic compounds. The limitation on the reactivity of triplet oxygen is overcome by the stepwise addition of a single electron, which can be provided by reduced transition metal ions, essentially iron(II) and copper(I). The sequential electron transfer leads to the formation of hydroperoxide radical (HOO^•), hydrogen peroxide (H₂O₂), and hydroxyl radical (HO^•). The later radical will oxidize almost any organic molecule found in wine and will react with the first species it encounters, depending on their concentration. Sulfur dioxide (SO₂) and ascorbic acid, when added to wine, are able to reduce the quinones. Alternative options have been assessed for the prevention of oxidation during wine storage; nevertheless, these are not fully understood or commonly accepted. During aging, aldehydes are important intermediates in the chemical transformations occurring in wines, leading to color and flavor changes. In the same way, a range of off-flavors can be formed from wine oxidation. At low concentrations these flavors may add to the complexity of a wine, but as these increase they begin to detract from wine quality. In addition to the major chemical browning involving wine phenols, the main oxidation reactions occurring during grape juice heating or storage are caramelization and Maillard reaction, which are temperature dependent. Different methods have been proposed in the literature, addressing the complexity and multi-scale related with the oxidation process, to attempt the quantification of antioxidant activity in wines. These methods can be broadly divided in: i) methods based on chemical reactions and ii) methods based on the chemical-physical properties of antioxidants.     

Correlation of methylglyoxal with acrylamide formation in fructose/asparagine Maillard reaction model system

α-Dicarbonyl compounds were highly reactive intermediates formed in Maillard reaction (MR), and o-phenylenediamine (OPD) was widely used as a trapping agent for α-dicarbonyl compounds. Both aqueous fructose/asparagine (Fru/Asn) and fructose/asparagine/o-phenylenediamine (Fru/Asn/OPD) model systems were heated at 150 °C for up to 30 min. Methylglyoxal (MG) was the main α-dicarbonyl compounds formed in MR, which was chosen as a representative of α-dicarbonyl compound to investigate the influence on acrylamide (AA) formation. The concentrations of AA, MG and Asn were detected during MR by HPLC method. The results indicated that the formation of AA increased with the heating time, and nearly 75% of AA was formed through the participation of α-dicarbonyl compounds. The amounts of formation and consumption of MG increased with heating time, and from 12 min of reaction, the consumed amounts of MG accounted for 62.1–90.3% on the basis of total amounts of MG formed in MR, suggesting that most of the MG took part in further reactions. Meanwhile, Asn concentration decreased with heating time in both models. The formation of AA and consumption of Asn were highly correlated with MG. Indeed, as MG concentration in MG/Asn model system decreased during heating at 150 °C, the concentration of AA significantly increased. The coefficient of correlation between consumed amounts of MG and the formed amounts of AA was 0.931, demonstrating that MG plays a role in AA formation.     

Occurrence of tetrodotoxin and paralytic shellfish poisons in a gastropod implicated in food poisoning in southern Taiwan

The toxicity of the gastropod Nassarius papillosus implicated in a food paralytic poisoning incident in Liuchiu Island, Taiwan, in October 2005 is reported. The symptoms of a victim (67 years old) were featured by general paresthesia, paralysis of phalanges and extremities, paralysis, coma, and aphasia. The remaining specimens of shell were assayed for toxicity. The range of specimen toxicity was found to be 63-474 mouse units (MU) per specimen for N. papillosus by a tetrodotoxin (TTX) bioassay. The mean (SD) toxicity of the digestive gland and other portions were 296 ± 120 and 382 ± 156 MU in N. papillosus. The toxin was partially purified from the acidic methanol extract of the gastropod by using a C18 solid-phase extraction column. The eluate was then filtered through a 3000 MW cut-off ultrafree microcentrifuge filter. It was shown that the toxin purified from gastropods analysed by high-performance liquid chromatography and liquid chromatography/mass spectrometry contained TTX 42-60 µg g^-1 (about 90%), whereas along with minor paralytic shellfish poisons (PSP) it was 3-6 µg g^-1 (about 10%).     

免疫学方法在食源性副溶血性弧菌检测中的应用研究进展

副溶血性弧菌可污染以海产品为主的各类食品,其引发的食品安全事件数量已经跃升至我国食品中毒事件数首位。相对于传统培养法及现代分子检测技术,基于抗原-抗体特异性识别反应的免疫鉴定及分型策略在检测效率、特异性、现场适用性、前处理简便性等诸多方面显现突出优势。本文在解析当前副溶血性弧菌抗体种类及制备方法的基础上,就免疫磁珠分离、酶联免疫吸附测定、免疫层析测试、免疫传感器、免疫荧光显微术等方法在食源性副溶血性弧菌检测中的应用现状进行综述,以期为该病原菌的快速检测提供借鉴和参考。     

HPLC测定鸡肉中呋喃唑酮的不确定度分析

近年来医学研究表明,呋喃唑酮具有很强的致癌性。鸡肉中呋喃唑酮是反映饲料添加剂中呋喃类药物含量的重要指标。本研究通过对高效液相色谱法测定鸡肉中呋喃唑酮残留量所得实验数据的分析和处理,对此法的不确定度进行了逐层分析,对测量结果的质量给出定量的说明,从而确定测量结果的可信程度。     

基于PCR技术的产真菌毒素镰刀菌分子诊断研究进展

镰刀菌属于自然界中最频繁产生毒素的真菌类别之一。该属真菌的毒素类次生代谢产物主要包括单端孢霉烯族化合物、伏马菌素和玉米赤霉烯酮3类,引起人畜各种生理异常甚至癌变。本文综述了3类镰刀菌毒素的结构和危害、生物合成的分子机理以及聚合酶链式反应(polymerase chain reaction,PCR)技术在其产生菌分子检测中的应用进展,突出了产毒真菌快速分子诊断技术在毒素早期预警、危害前置化干预中的意义。同时,在剖析现有产毒真菌PCR检测体系可能存在问题的基础上,提出克服瓶颈方法和进一步提高体系可靠性的有效策略。