气相色谱-串联质谱法测定柑橘中5种杀螨剂残留

建立了气相色谱-串联质谱法(GC-MS/MS)检测柑橘中5种杀螨剂残留分析方法。样品经乙腈提取、氯化钠盐析后,取有机相用Qu EChERS方法净化,利用GC-MS/MS在多反应监测(MRM)模式下进行测定,外标法定量。5种杀螨剂在0.005~0.5mg/L浓度范围内呈现良好的线性关系,相关系数r^2均>0.996,方法定量限为0.005 mg/kg。在0.005、0.01和0.1mg/kg 3种添加水平下,加标回收率为70.6%~111.3%,相对标准偏差(RSD)为1.07%~14.64%。本方法简便、重现性良好,可用于柑橘类水果样品中杀螨剂的日常检测。     

玉米雄性不育K932MS不育株和可育株生理生化特性的比较研究

通过比较分析K932MS中不育及可育花药不同发育时期的可溶性糖、可溶性蛋白、游离脯氨酸含量及过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性差异,探讨其败育的生理生化机制。结果表明,不育花药中可溶性糖、可溶性蛋白含量在造孢细胞时期、花粉母细胞时期、二分体和四分体时期均显著低于可育花药,游离脯氨酸含量二分体和四分体时期显著低于可育花药;不育花药中CAT活性在造孢细胞时期显著高于可育花药,在花粉母细胞时期和四分体时期显著低于可育花药;SOD活性在花粉母细胞时期显著高于可育花药,在二分体和四分体时期都显著低于可育花药;POD酶活性在造孢细胞时期和四分体时期显著高于可育花药。造成K932MS败育的原因可能是由于不育花药中营养物质的严重不足,同时不育花药的CAT和SOD活性降低、POD活性升高,不利于花药的正常生长发育。     

Lactococcus lactis,causative agent of an endocarditis valvularis and parietalis thromboticans in the allis shad,Alosa alosa (L.)

Since the 1940s, the anadromous allis shad, Alosa alosa (L.), has suffered population declines throughout its distribution range in Europe. In context of EU‐LIFE projects for the reintroduction of the allis shad in the Rhine system, a comprehensive study was started in 2012 to investigate infectious diseases occurring in allis shad. In course of the study, 217 mature and young‐of‐the‐year allis shad originating from the wild population from the Gironde–Garonne–Dordogne system (GGD‐system) and the Rhine system as well as 38 allis shad from the breeding population were examined by use of bacteriological and histological methods. In 2012 and 2014, an endocarditis valvularis thromboticans caused by a coccoid bacterium was detected in 16% and 25% of mature allis shad originating from the GGD‐system. Results of microbiologic examinations, including biochemical characteristics, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) and 16S rRNA gene sequence analysis, revealed Lactococcus lactis as causative agent of this infection. This is the first report of an endocarditis valvularis and parietalis thromboticans caused by Lactococcus lactis in fish. Possible sources of infection as well as the impact for the reintroduction programme are discussed.     

Detection of seven phytohormones in peanut tissues by ultra-highperformance liquid chromatography-triple quadrupole tandem mass spectrometry

Development of highly sensitive and reliable method for detection of phytohormones is of great significance to study plant hormones and agricultural production.In this study,an ultra-high-performance liquid chromatography-mass spectrometry/mass spectrometry method was established for separation and quantification of trans-zeatin,trans-zeatin riboside,gibberellin A_3,indol-3-acetic acid,salicylic acid,abscisic acid,and jasmonic acid(JA) without any label.The sepa ration was performed on an Agilent Explus Plus C18 column by using methanol and water as mobile phases with gradient elution.The target compounds were confirmed and quantified by mass spectrum via positive electrospray ionization for trans-zeatin,transzeatin riboside,indole-3-acetic acid,and via negative electrospray ionization for gibberellin3,salicylic acid,abscisic acid,and JA.The limits of detection ranged from 0.0127 ng L~(-1) for gibberellin A_3(GA_3) to 33.26 ng L~(-1) for JA and were lower than the currently reported values in literature.The proposed method was applied for qualitative and quantitative analyses of phytohormones in peanut gynophores and pods.The recoveries of the spiked phytohormones ranged from 80.20 to102.56%.The contents of seven endogenous hormones varied specifically in different development stages of peanuts.This study provides a highly sensitive and selective detection method for hormones and elucidates the growth and development of the gynophore and peanut fruit,which are controlled by seven endogenous hormones.     

MS培养基中氮、磷无机盐对鳗草克隆幼苗生存的影响

为了探究MS培养基中氮、磷无机营养盐对鳗草生长的影响。单独添加不同浓度KNO₃、NH₄NO₃和KH₂PO₄的天然海水中培养鳗草克隆苗,于7、14天进行植株形态学观察和叶片叶绿素含量测定。其中,KNO₃的添加量为MS培养基中的1/2倍、1倍和2倍及NO₃^-总浓度为39.4 mmol/L,KH₂PO₄和NH₄NO₃的添加量均为MS培养基中各自浓度的1/2、1和2倍。结果表明,叶绿素含量以KNO₃处理组最高(P<0.05),克隆苗培养14天无毒害现象,且有新叶发出;NH₄NO₃和KH₂PO₄处理组均对克隆苗有明显毒害作用,NH₄NO₃处理组叶片48 h后开始褐化,7天后茎尖、根尖明显变软并褐化,14天后植株死亡;KH₂PO₄处理组培养14天后叶片平均褐化率达56%。因此,1/2、MS培养基均不适用于鳗草的室内培养,其培养基的氮源应为单独添加的NO₃^--N或高浓度NO₃^--N+低浓度NH₄⁺-N。     

5种动物源食品中的氟虫腈及其3个代谢物残留量检测

利用QuEChERS技术结合超高效液相色谱-串联质谱的方法检测5种动物源食品(鸡肉、鸡蛋、猪肝、牛奶、猪肉)中氟虫腈及其3个代谢物残留量。样品用乙腈提取,经低温处理,多壁碳纳米管(MWCNTs)、弗罗里硅土(Florisil)和C18分散固相萃取(d-SPE)净化,外标法定量。在不同浓度的加标水平下,氟虫腈及其代谢物在5种动物源食品中的平均回收率为72.1%～113.8%,相对标准偏差RSD为1.9%～17.6%,检出限LOD在0.73～1.94μg/kg范围内,定量限LOQ在5～10μg/kg范围内。该方法具有简单、灵敏、准确等优点,适用于动物源食品中氟虫腈及其代谢物的快速筛查和定量检测。     

鼓槌石斛不同花期香气成分及盛花期香气日变化规律研究

[目的]本研究明确鼓槌石斛花朵挥发性成分及其释放量变化,阐明其花香气形成的物质基础,为石斛属植物花香研究提供理论基础。[方法]以鼓槌石斛原生种为材料,运用固相微萃取(SPME)结合GC-MS技术测定鼓槌石斛不同花期及盛花期时一天中不同时段花朵挥发性成分及其释放量变化。[结果]从鼓槌石斛花朵释放的花香中共鉴定出花香成分33种,其中,萜烯类15种,酯类7种,醇类6种,芳香族化合物2种,酮类2种,醛类1种;鼓槌石斛花香成分主要为酯类和萜烯类,其释放量占总香气成分的80%以上。鼓槌石斛盛花期花朵随一天中开放时段的不同,香气成分种类和释放量皆呈先上升后下降的趋势,其中,香气种类和释放量均在14:00时达到最高。鼓槌石斛不同花期挥发性成分中的酯类、萜烯类、醛类、醇类、酮类和芳香族化合物的种类和释放量皆呈先上升后下降的趋势,在盛花期达到最高。[结论]本研究明确鼓槌石斛花朵不同花期及盛花期一天中的不同时段挥发性成分及释放量差异明显,乙酸辛酯、β-罗勒烯、α-蒎烯和苯乙醛是影响鼓槌石斛香气的主要物质,为探讨石斛兰香气形成机制和香花型石斛兰育种提供参考。     

基于nanoUPLC-MS/MS的螺旋藻游离肽组成分析

为了研究螺旋藻中的多肽成分,以钝顶螺旋藻为原料,采用超滤法提取螺旋藻中的游离肽,利用nanoUPLC-MS/MS和PEAKS Studio分析谱图信息,结合NCBI数据库进行比对和从头测序分析,获得游离肽的结构组成和百分含量信息。结果表明,利用数据库比对法和从头测序法,分别得到可信的游离肽4 485个和20 597个,匹配到的蛋白质有1 036种。数据库比对结果中的游离肽主要为七肽到二十一肽,少量为二十一肽以上;从头测序结果中游离肽主要为二肽到十六肽,少量为十六肽以上。数据库比对结果中百分含量最高的游离肽是十肽,为15.95%;从头测序结果中百分含量最高的是五肽,达到24.09%。本研究结果为螺旋藻蛋白资源的进一步开发和利用提供了依据。     

超高效液相色谱-串联质谱法测定牛奶和奶粉中五种苯并咪唑类药物

为建立牛奶及奶粉中5种苯并咪唑类药物(阿苯达唑、芬苯达唑、奥芬达唑、噻苯达唑、苯硫氨酯)简便、准确的分析检测方法,以固相萃取为净化手段,采用Acquity UPLC^® BEH C₁₈(100 mm×2.1 mm,1.7 μm)色谱柱进行分离,电喷雾离子源(ESI⁺),多反应监测(MRM)模式检测。结果表明,5种苯并咪唑类药物在1~500 μg·L^-1范围内呈线性相关,相关系数(r)均大于0.996,加标平均回收率介于91.7%~97.8%之间,相对标准偏差(RSD)在1.4%~6.5%之间,基质效应均小于15%。5种药物的检出限均在0.1~3 μg·kg^-1范围内,定量限均在0.5~10 μg·kg^-1范围内。该方法操作简单、快速且灵敏度高,重现性好,能够用于牛奶及奶粉5种苯并咪唑类药物的同时测定。     

用液相色谱串联质谱法测定渔业水样中6种农药的含量

本文建立了一种快速检测渔业水质样本中酰胺类除草剂乙草胺、丙草胺、丁草胺、三嗪类除草剂莠去津、烟碱类杀虫剂噻虫嗪、三唑类杀菌剂苯醚甲环唑6种农药含量的液相色谱串联质谱法。采用乙腈-水-甲酸梯度洗脱、电喷雾电离方式、多反应监测模式测定考察检出限、线性范围、日内精密度及日间精密度。在三种加标浓度下,该方法的回收率为78.2%~104.7%。用液相色谱-四级杆-飞行时间质谱对疑似目标物质进行定性,用精确质量数、同位素丰度比和二级碎片解析方式等解析定性结构。该方法能够满足检测这六种农药的要求,能准确定性,自建的谱库可为渔业污染事故鉴定和水产品质量安全风险评估做支撑。