QuEChERS技术结合超高效液相-串联质谱同时测定薄皮甜瓜中7 种葫芦素

采用改良的QuEChERS方法，建立同时测定甜瓜中7 种葫芦素的超高效液相色谱-串联质谱检测方法。样品用乙腈提取，离心后取1 mL上清液经50 mg乙二胺-N-丙基硅烷和50 mg十八烷基硅烷净化，使用XBridge C18色谱柱分离，以乙腈和0.1%甲酸加5 mmol/L乙酸铵溶液为流动相进行梯度洗脱，采用电喷雾离子源电离，正/负离子快速切换多反应监测模式进行分析。在此条件下，7 种葫芦素在16 min内得到较好分离，在0.1～1 500 μg/L质量浓度范围内线性关系良好，相关系数均大于0.99；进行3 个水平添加实验（n=5），7 种葫芦素在20、100 μg/kg和500.0 μg/kg三个添加水平下的回收率在75.7%～118.3%之间，相对标准偏差在0.5%～13.6%之间，该方法的检出限及定量限分别为0.16～4.33 μg/kg和0.27～13.11 μg/kg。该方法简便、灵敏度高、分析时间短，精密度和准确性良好，可用于甜瓜中7 种葫芦素的同时检测。     

固相萃取净化-超高效液相色谱串联质谱法测定菜籽油中交链孢霉毒素含量

建立了固相萃取净化-超高效液相色谱串联质谱法测定菜籽油中交链孢霉毒素含量的方法。将菜籽油与甲醇混匀后使用 Captive EMR-Lipid 固相萃取柱（3 mL, 300 mg）净化,收集净化液经氮吹浓缩后,采用超高效液相色谱串联质谱测定,内标法定量。以回收率为指标对固相萃取柱的净化载量及洗脱剂体积进行优化。结果表明,菜籽油最佳净化载量为0.15 g,最佳洗脱剂体积为2.0 mL。4种交链孢霉毒素在线性范围内相关系数均大于0.998,4种交链孢霉毒素加标回收率为688%~117.3%,精密度为8.6%~11.4%,方法检出限为0.1~2.0 μg/kg,定量限为0.3~6.0 μg/kg。方法具有较好的灵敏度及回收率,简单、易于操作,适用于菜籽油中交链孢霉毒素的检测。     

基于PriME净化的高效液相色谱-串联质谱法检测水产品中9种生物胺

建立了高效液相色谱串联质谱法同时测定水产品中9种生物胺含量的检测方法。样品通过酸化乙腈提取,用PriME HLB固相萃取柱净化,通过HILIC色谱柱分离,在正离子多反应监测模式下分析定量。结果表明,在1~200 ng/mL的浓度范围内线性良好,相关系数大于0.999,在15、30、50 μg/kg 添加水平下,平均回收率在80.5%~109.5%之间,相对标准偏差为2.3%~5.9%,方法检测限为5 μg/kg,定量限为15 μg/kg。该方法简单、快速、具有良好的灵敏度、回收率和精密度,适用于水产品中低浓度生物胺的检测。     

SPE结合超高效液相色谱-质谱/质谱仪测定鸡蛋中的万古霉素和去甲万古霉素残留量

建立了固相萃取法(SPE)结合超高效液相色谱-质谱/质谱仪(UPLC-MS/MS)测定鸡蛋中万古霉素和去甲万古霉素残留量的方法。样品采用0.1%甲酸水溶液进行提取,Strata-X-C固相萃取柱进行净化,UPLC-MS/MS正离子模式扫描,多反应监测模式(MRM)测定,外标法定量。结果表明:万古霉素和去甲万古霉素在5.0~100.0 μg/L浓度范围线性关系良好(r均大于0.999),检出限为2.0 μg/kg,定量限为5.0 μg/kg,加标平均回收率为85.6%~96.3%,相对标准偏差为3.7%~9.2%。该方法灵敏度高,准确度好,能满足对鸡蛋中万古霉素和去甲万古霉素定量分析的要求。     

分子印迹固相萃取-超高效液相色谱-串联质谱法测定牛奶中11种氨基糖苷类抗生素

目的：建立分子印迹固相萃取-超高效液相色谱-串联质谱（UPLC-MS/MS,Ultra Performance Liquid Chromatography Tandem Mass Spectrometry）检测牛奶中11种氨基糖苷类抗生素（巴龙霉素、妥布霉素、庆大霉素、卡那霉素、阿米卡星、安普霉素、链霉素、双氢链霉素、新霉素、壮观霉素、潮霉素B）残留的测定方法。方法：样品经5%三氯乙酸-乙腈提取,氨基糖苷类分子印迹聚合物（MIP）固相萃取柱净化,SiELC Obelisc R色谱柱分离,采用超高效液相色谱-串联质谱仪进行测定。结果：方法检出限为1.0~5.0 μg/kg,定量限为2.0~10.0 μg/kg。11种氨基糖苷类药物在1.0~500 μg/kg范围内关系良好（r2>0.9911）,牛奶中加标回收率为70.7%~115.6%,相对标准偏差（RSD,relative standard deviation, n=6）为1.1%~9.8%。结论：本方法准确度、灵敏度高,可用于牛奶中11种氨基糖苷类抗生素的同时检测。     

固相萃取-高效液相色谱法测定苹果汁及其饮料中展青霉素的含量

建立固相萃取-高效液相色谱法测定苹果汁及其饮料中展青霉素含量的检测方法。样品经预处理后,采用固相萃取柱净化处理,以乙腈-水作为流动相,C18色谱柱分离,二极管阵列检测器进行检测。结果表明：方法检出限为8 μg/kg,方法定量限为25 μg/kg;展青霉素标准溶液在50.0～500.0 μg/L质量浓度范围内,决定系数R2为0.999 6;样品中展青霉素含量为25～100 μg/kg时,回收率在90.2%～102.8%之间,精密度（变异系数）为0.57%～1.44%。此方法准确度较高,成本适中,操作较简便,适合苹果浓缩汁生产企业用于产品安全自控。     

Oasis PRiME HLB-高效液相色谱-串联质谱法测定黄鱼中的碱性嫩黄O

目的 建立Oasis PRiME HLB-高效液相色谱-串联质谱法测定黄鱼中的碱性嫩黄O的分析方法。方法 样品经乙醇提取液充分提取, 经涡旋、超声、低温高速离心后, 上清液过Oasis PRiME HLB固相萃取柱净化, 流出液经氮吹吹干, 复溶, 待质谱分析。结果 在1.5、15.0、30 μg/L 3个加标浓度下, 回收率为85.3%~ 94.8%, 相对标准偏差为3.0%~7.2%, 方法定量限为1 μg/kg。结论 该方法前处理十分简便, 固相萃取净化水平高, 色谱串联质谱分析快速灵敏, 回收率高, 灵敏度高, 适合黄鱼中非食用物质碱性嫩黄O的定性定量 分析。     

LC-MS/MS法测定柚子皮中香豆素类物质组成及含量

针对6份不同品种的柚子皮,采用甲醇超声提取,Oasis HLB固相萃取柱净化,Waters XBrigde C18色谱柱分离,以乙腈和0.05 mol/L乙酸铵溶液(含0.1 %甲酸)为流动相进行梯度洗脱,采用多反应监测(multiple reaction monitoring, MRM)检测,建立液相色谱-质谱法(liquid chromatography-mass spectrometry, LC-MS/MS)测定柚子皮中香豆素类物质组成及含量的检测方法。结果表明:在0.010 μg/mL^1.0 μg/mL范围内,8种香豆素及其衍生物具有良好的线性关系(R2≥0.999 5);方法检出限在3.0 μg/kg^4.5 μg/kg,定量限在10.0 μg/kg^15.0 μg/kg;加标回收率在90.4 %~98.5 %,相对标准偏差在0.9 %~4.1 %;在柚子皮中检出7-甲基香豆素、7-甲氧基香豆素、7-乙氧基-4-甲基香豆素、醋硝香豆素,其中7-甲氧基香豆素含量较高,含量在11.4 μg/kg^123.7 μg/kg,该成分可能与柚子具有暖胃、化痰、润化喉咙等食疗作用相关,这为柚子皮综合开发利用提供参考。     

水产品中氯霉素检测条件的优化

目的建立液相色谱串联质谱法测定加工水产品中的氯霉素,并对提取溶剂、净化条件、流动相进行了优化。方法样品采用乙酸乙酯提取,HLB固相萃取柱净化,C_(18)色谱柱分离,ESI源负离子模式对氯霉素进行检测。结果氯霉素在0.1~10μg/kg范围内线性关系良好,相关系数为0.999,在基质样品中添加0.1、0.2和10.0μg/kg 3个水平药物,其回收率在95.0%~103.2%之间,相对标准偏差3.72%~6.85%,方法检测限为0.1μg/kg.结论该方法可靠、稳定,可满足加工水产品中氯霉素残留检测与确证需要。     

亲水作用高效液相色谱-串联质谱法测定薯片及饼干中丙烯酰胺的含量

目的 建立亲水作用高效液相色谱-串联质谱法测定薯片及饼干中丙烯酰胺含量的分析方法。方法 薯片及饼干经超纯水提取, 正己烷除脂, Cleanert? ACA固相萃取柱净化, BEH Amide色谱柱(2.1 mm×100 mm, 1.7 μm)分离, 并以0.1%(V:V)甲酸水-乙腈溶液=2:8(V:V)为流动相, 电喷雾正离子模式电离, 多反应监测模式检测, 内标法定量。结果 丙烯酰胺在5~2000 μg/L范围内线性关系良好, 相关系数大于0.999。方法的检出限(S/N＞3)和定量限(S/N＞10)分别为3 μg/kg和10 μg/kg。在不同基质中, 丙烯酰胺在20、200、1000 μg/kg的添加水平下平均加标回收率为91.5%~98.2%, 相对标准偏差为2.71%~4.82%。结论 此方法具有准确度好、灵敏度高等特点, 适用于薯片及饼干中丙烯酰胺的测定。     

葫芦素B对过氧化氢诱导的大鼠肝细胞凋亡的抑制作用

葫芦素B是从甜瓜茎中提取的药用成分，以前的研究成果已经发现，该药具有保肝作用。但是其作用机制还不是很清晰，本实验探讨的是葫芦素B是否通过抑制凋亡信号转导而达到保肝的目的。过氧化氢诱导的乳鼠凋亡模型，然后给与不同剂量三个浓度的葫芦素B（3、10、30mmol／L）。通过流式细胞计量术测量细胞早期凋亡率。与模型组比较，高中剂量组能明显降低肝细胞早期的凋亡率（p〈0．05）。上述结果表明葫芦素B能抑制过氧化氢诱导的乳鼠肝细胞的凋亡，从而达到保肝的药理学作用。     

超声波辅助提取甜葫芦中葫芦素E的工艺研究

对超声波辅助提取甜葫芦中葫芦素E的工艺进行研究。在单因素试验的基础上,通过正交试验优化葫芦素E的提取条件。确定甜葫芦中葫芦素E超声波辅助提取的最佳工艺为：料液比为1∶10（g/mL）,甲醇体积分数为70%,提取时间为15 min,超声波功率500 W,此条件下的葫芦素E得率为0.695%。     

两起食用苦葫芦瓜引起的食物中毒调查报告

目的 调查衢州市发生的两起食物中毒事件,确定事件发生原因,为预防和控制类似中毒事件提供依据和建议。方法 对衢州市2020年和2021年发生的两起食物中毒事件开展流行病学调查,综合分析食物暴露史、临床症状与特征、实验室检测结果等判定事件发生的性质。结果 两起食物中毒事件病例共14例,潜伏期为20 min~4 h;临床症状相似,主要为腹泻、恶心、呕吐、腹痛、头晕等。病例均有苦葫芦瓜进食史。经超高效液相色谱-大气压化学电离-三重四级杆质谱法检测,苦葫芦瓜样品中苦葫芦素B含量为150 mg/kg,含有苦葫芦瓜的剩菜样品中苦葫芦素B含量为69.9 mg/kg,一份病例血液标本中苦葫芦素B含量为2.7 μg/L、5份尿样苦葫芦素B含量为0.14~0.59 μg/L。结论 本地两起食物中毒是由苦葫芦瓜引起,建议加强对食品从业人员和广大群众的健康教育,防止中毒事件发生。     

Recombinant yeast as a functional tool for understanding bitterness and cucurbitacin biosynthesis in watermelon (Citrullus spp.)

Cucurbitacins are a group of bitter‐tasting oxygenated tetracyclic triterpenes that are produced in the family Cucurbitaceae and other plant families. The natural roles of cucurbitacins in plants are probably related to defence against pathogens and pests. Cucurbitadienol, a triterpene synthesized from oxidosqualene, is the first committed precursor to cucurbitacins produced by a specialized oxidosqualene cyclase termed cucurbitadienol synthase. We explored cucurbitacin accumulation in watermelon in relation to bitterness. Our findings show that cucurbitacins are accumulated in bitter‐tasting watermelon, Citrullus lanatus var. citroides, as well as in their wild ancestor, C. colocynthis, but not in non‐bitter commercial cultivars of sweet watermelon (C. lanatus var. lanatus). Molecular analysis of genes expressed in the roots of several watermelon accessions led to the isolation of three sequences (CcCDS1, CcCDS2 and ClCDS1), all displaying high similarity to the pumpkin CpCPQ, encoding a protein previously shown to possess cucurbitadienol synthase activity. We utilized the Saccharomyces cerevisiae strain BY4743, heterozygous for lanosterol synthase, to probe for possible encoded cucurbitadienol synthase activity of the expressed watermelon sequences. Functional expression of the two sequences isolated from C. colocynthis (CcCDS1 and CcCDS2) in yeast revealed that only CcCDS2 possessed cucurbitadienol synthase activity, while CcCDS1 did not display cucurbitadienol synthase activity in recombinant yeast. ClCDS1 isolated from C. lanatus var. lanatus is almost identical to CcCDS1. Our results imply that CcCDS2 plays a role in imparting bitterness to watermelon. Yeast has been an excellent diagnostic tool to determine the first committed step of cucurbitacin biosynthesis in watermelon. Copyright © 2014 John Wiley & Sons, Ltd.     

The determination of bitter principles in zucchinis

A method using reverse phase thin layer and high performance liquid chromatography was developed to determine the level of the bitter principle occasionally found in zucchini (Cucurbita pepo L.). The system gave excellent separation with recovery rates of about 90% from spiked fruit. The bitter principle was confirmed by C¹³ NMR and mass spectrometry as cucurbitacin E glycoside which was present in concentrations in the order of 600mg kg^?1 in bitter fruits. Bitterness was detected by a taste panel at cucurbitacin E glycoside concentrations of 1 mg kg^?1 in aqueous solutions and 2 mg kg^?1 in zucchini pulp. The method described should assist the screening for bitterness in commercial and breeding populations of zucchini.     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.