气相色谱-质谱法测定鸡肉组织中氯霉素残留的研究

气相色谱-质谱法（GC-Ms）检测鸡肉组织中氯霉素的残留量。用乙酸乙酯提取鸡肉组织中的氯霉素，用正己烷净化，BSTFA＋TMCS衍生。采用负化学电离源（CI）方式进行选择离子扫描（SIM），选择离子包括376，378，466，468，470。方法的检测限为0．1μg／kg（S／N》10），线性范围为0．5-50μg／kg，加标回收率为70．0％-94．0％，相对标准偏差（n=5）为8．58-12．50％。该法具有灵敏度高，实用性强和操作简单等优点。     

套袋对红富士苹果果实芳香成分的影响

以短枝红富士苹果(Malusdomesticacv.RedFujiSpur)为试材,顶空固相微萃取法(HS-SPME)提取芳香成分,GC-MS定性、定量分析,研究套袋对红富士苹果果实芳香成分的影响。结果表明,未套袋红富士苹果的芳香成分中酯类、醛类和醇类化合物的相对含量均较高,分别为42.18%、29.65%和17.75%,但以酯类化合物含量最高,可将其划为“酯香型”苹果品种。套袋后红富士苹果果实风味变淡,芳香成分总量仅相当于未套袋果的91.38%;而且由于酯类和醇类物质均有不同程度地降低,分别相当于未套袋果的42.75%和82.98%,醛类为未套袋果的1.77倍,使红富士苹果的特有风味有所改变。     

GC-MS联机技术对克菌丹原药及其主要杂质的定性分析

气相色谱和质谱联机是分离和检测有机物及其杂质和代谢产物,并进行定性定量的一种有效方法。本文采用GC-MS对克菌丹原药主成分及其主要杂质进行定性分析,并确定了2个主要杂质。GC条件为:HP-5毛细管色谱柱(30m×0.25mm×0.25um),氦气1mL/min,进样口温度200℃,柱温从50℃(1min)→200℃(10℃/min,2min)→280℃(20℃/min,2min),进样量1μL。MS条件为,离子源230℃,扫描范围12~350amu。     

Floral fragrances of Hemerocallis L. (daylily) evaluated by headspace solid-phase microextraction with gas chromatography-mass spectrometry

Traditional breeding objectives focusing on flower type and colour have resulted in the lack of floral fragrances in modern daylilies. Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to determine the contributions of floral volatiles to floral fragrances in 46 daylilies (seven species, one variety, and 38 cultivars). Thirty-seven floral volatiles were identified, including 30 terpenoids, five benzenoids, and two nitrogenous compounds. Sensory evaluation and HS-SPME-GC-MS revealed that variations in the relative emission rates and proportions of (E)-β-ocimene and linalool were mainly responsible for different fragrance patterns in Hemerocallis. The studied daylilies were grouped to six fragrance patterns: (1) intense herbaceous and pungent scent, having the highest (E)-β-ocimene emission level; (2) intense flowery and pungent scent, having medium (E)-β-ocimene and low linalool emission levels; (3) medium flowery and sweet scent, having very low (E)-β-ocimene and the highest linalool emission levels; (4) low flowery and fresh scent, having low (E)-β-ocimene and no linalool emission levels; (5) very low herbaceous and fresh scent, having very low (E)-β-ocimene and linalool emission levels; and (6) no scent, having trace amounts of floral volatiles.     

植物乳杆菌发酵砀山梨汁香气成分的变化过程分析

砀山梨汁经乳酸菌发酵可用于开发益生菌发酵饮料。基于固相微萃取技术联合气相色谱-质谱（SPME-GC-MS）定性和定量分析,对植物乳杆菌发酵砀山梨汁在不同发酵时间其香气成分的变化过程进行了分析。结果表明,发酵过程共检测出以酚类、醛类、醇类、烃类、酯类、酮类及酸类等为主共66种挥发性气味物质。其中,在未发酵的砀山梨汁中检测到26种香气成分物质,其特征香气物质包括：正己醛、糠醛、癸醛、壬醛、2-乙基己醇、1-己烯、甲酸辛酯、大马酮等。此外,在不同发酵阶段,发酵梨汁中挥发性香气物质的种类及含量均发生动态变化;经发酵6、12、24、36和48 h,分别由发酵梨汁中检测出25、20、28、28和32种气味物质。其中,当发酵48 h时,风味物质组成最为丰富,总计共检测到32种香气成分物质,主要包括：糠醇、正己醇、1-辛醇、1-癸醇、3-甲基-2-庚醇、羟基丙酮、顺式-1, 2-二甲基环戊烷、甲酸己酯、3, 3-二甲基-2, 4-戊二酮、乙酸甲酯、大马士酮等,这些香气物质可赋予发酵梨汁清新的花香和果香。同时,感官评价结果亦表明,梨汁经植物乳杆菌发酵48 h可获得最佳感官品质。结果表明,砀山梨汁经植物乳杆菌发酵可赋予其新的特征风味,并改善其感官品质,可为乳酸菌发酵砀山梨汁饮料的开发提供理论依据。     

两个杏品种果实香气成分的气相色谱—质谱分析

 对两个杏品种‘新世纪’、‘红丰’成熟期果实采用蒸汽蒸馏—萃取法提取香气成分, 进行气相色谱—质谱分析鉴定。新世纪检测出74 种成分, 占总峰面积的73.604 %; 红丰检测出72 种成分, 占总峰面积的44.677 %。主要成分为醇类、醛类、内酯类、酮类化合物。相同成分有紫罗酮、己醛、己醇、己烯醛、己烯醇、内酯类、萜烯醇类等, 这些成分共同构成杏果实的香味, 但其含量在两个品种间存在差异。     

冬虫夏草新药效成分分析

利用GC -MS对人工培养冬虫夏草菌丝的挥发油进行了成分分析 ,从中检出一种与贝母碱结构类似的物质———Verticiol。证实冬虫夏草是一种对呼吸道疾病有特效的药物     

Evaluation of field resistance in field-collected mosquito Culex quinquefasciatus Say through quantification of ULV permethrin/PBO formulation in field bioassays

BACKGROUND

Pyrethroids are among the most applied adulticides worldwide to control mosquito vectors for prevention of arboviral diseases transmission. However, pesticide resistance development in a mosquito population could lead to decreased control efficacy. While most studies investigate the resistant genotype (i.e. kdr, CYP450, etc.) as explanatory variables, few field efficacy studies have measured pesticide quantities deposited at different distances from the sprayer in association with observed mosquito mortality. The current study determined field delivered amounts of an applied ULV permethrin/PBO formulation (31% permethrin + 66% piperonyl butoxide) by GC/MS and estimated practical resistance ratios using caged mosquito females.

RESULTS

For field samples, the extraction method recovered 78 ± 3.92–108 ± 8.97% of the permethrin/PBO formulation when utilizing the peaks of PBO from GC/MS to estimate the concentrations of adulticide deposited near the mosquito cages. The field bioassay showed that the spatial distribution of permethrin/PBO formulation was heterogeneous among three pseudo-replicates within the same distance. Within the quantifiable permethrin/PBO range of 15.7–51.4 ng/cm², field-collected mosquito mortalities started at 64% and linearly increased reaching 100% only in two areas, while all Sebring susceptible mosquitoes died. The field LC₉₅ resistance ratio (RR) of F₀ Cx. quinquefasciatus ranged from 2.65–3.51, falling within the 95% CI of RR₉₅ estimated by laboratory vial assays. Tests with and without PBO indicated P450's enzymes contributed to field resistance.

CONCLUSION

Results showed the suitability of the collection and quantification method to estimate the field resistance ratio at the applied pesticide rate. Pesticide quantification would also allow the association of the known frequencies of resistance mechanisms (e.g. kdr, CYP450) with field mortalities to estimate the resistance level conferred by such mechanisms. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

邓恩桉组织材料生根抑制物研究

进行了邓恩桉组织体内生根抑制物的研究,分别从对受试材料的生物效应、提取液化学鉴定、提取液GC-MS分析等3方面进行了试验。结果显示:邓恩桉组织材料提取液对受试材料基本都呈现不同程度的抑制作用,其中成树两个材料的提取液抑制强度较强,而萌枝茎段和幼苗茎段的提取液抑制强度次之,与酚类化学鉴定中表明的浓度大小趋势基本一致,表明酚类物质在生根抑制效应中起着重要的作用。但邓恩桉萌枝茎段提取液的GC-MS分析没有检测到酚类物质,而是以醇类物质及其衍生物为主,其中1,8-桉树脑为最主要的成分,与多种桉树桉叶油的组成成分相似。究其原因,可能与提取液处理的方法和酚类物质的相对含量大小有关。     

箬竹叶挥发性成分的GC—MS分析

采用水蒸汽蒸馏，GC-MS联用技术，对知竹叶挥发性成分进行提取、分离和鉴定，共分出了47个色谱峰，鉴定了其中的43种成分，占挥发性成分总量的96.45%，含量最高的为4-乙烯基苯酚，含量为15.26%，其次为3-已烯酸，含量为10.06%。在43种成分中醛类化合物共有在2种，其含量占挥发性成分总量的27.49%，羧酸类化合物8种，其含量占挥发性成分总量的23.54%。