毛细管气相色谱法检测高蛋白食品中甜蜜素

建立了检测高蛋白食品中甜蜜素的毛细管气相色谱分析方法。选择HP-INNOWAX型毛细管色谱柱作为分离柱,采用氢火焰离子化检测器。试样经超声提取、沉淀剂去蛋白质和脂肪,离心定容后过滤,取其滤液进行衍生化反应,根据甜蜜素衍生反应机理,控制反应条件,在正己烷萃取衍生产物后的20 h内以毛细管气相色谱检测甜蜜素的含量。结果表明,甜蜜素的质量浓度在0.05~0.83mg/m L范围内与峰面积呈线性关系良好,相关系数为0.9995。当液体取样量25g时,方法的检出限为0.001g/kg;当固体取样量5g时,方法的检出限为0.005g/kg。回收率在94.2%~102.9%之间,相对标准偏差在2.8%~6.1%之间。该方法解决了高蛋白样品在实验过程中易乳化和杂质干扰等问题,检出限低,检测结果准确可靠、重复性好,适合于高蛋白食品中甜蜜素质量浓度的检测。     

毛细管气相色谱法测定聚氯乙烯食品包装中的氯乙烯单体

研究采用毛细管气相色谱法检测聚氯乙烯薄膜中残留的氯乙烯单体,并用气相色谱质谱法进行确证.样品中的氯乙烯单体采用静态顶空技术提取.利用极性毛细管气相色谱柱进行分离并结合氢火焰离子化检测器进行高灵敏度检测.氟乙烯单体在0.05～0.2 mg/L的浓度范围内有较好的线性关系,相关系数为0.999,相对标准偏差在3.1%以内,检测低限为0.5 mg/kg,该方法具有较好的检测精密度和灵敏度.     

气相色谱-质谱联用法测定水溶肥料中10种拟除虫菊酯类农药含量

目的建立气相色谱-质谱联用法测定肥料中10种拟除虫菊酯农药的分析方法。方法样品经丙酮超声提取,DB-5MS毛细管气相色谱柱分离,用气相色谱-质谱法测定。结果 10种化合物浓度在各自线性范围内与相应峰面积呈线性关系,相关系数r 0.990,加标回收率为78.12%～120.63%,精密度(relative standard deviation,RSD)为1.24%～11.91%。称样量为0.5 g时,联苯菊酯检出限为0.06 mg/kg;醚菊酯检出限为0.1mg/kg;甲氰菊酯、氯菊酯、氟胺氰菊酯检出限为0.2 mg/kg;氯氟氰菊酯、氟氯氰菊酯、氯氰菊酯、氰戊菊酯、溴氰菊酯检出限为0.4 mg/kg。结论该方法样品前处理简单、快捷,重复性及回收率均能达到检测分析要求,可以应用于水溶肥料中拟除虫菊酯农药的检测。     

涂料中卡拉花醛同分异构体总含量的测定

建立气相色谱-质谱联用法测定涂料中卡拉花醛同分异构体的总含量,以甲醇为萃取溶剂,超声萃取涂料中的卡拉花醛,萃取液直接进行气相色谱-质谱/选择离子监测法测定,外标法定量。该方法检出限为2.5 mg/kg,在3～60μg/mL范围内,峰面积与质量浓度间存在良好的线性关系;当加标水平分别为9.95、49.9 mg/kg时,平均加标回收率为85%～90%。为验证本标准测试方法的适用性,选取了15个样品进行验证试验,有13个样品未检出,其他两个样品含量分别为19.4 mg/kg和5.50 mg/kg,相对标准偏差为4.5%和4.9%。该方法简便快速,准确可靠,易于操作,适用于涂料中卡拉花醛的日常分析测试。     

SO2熏蒸处理对维多利亚葡萄保鲜效果研究

以维多利亚葡萄为试材,研究1000、500、100μL/L三种不同浓度SO2熏蒸处理1h对0℃贮藏条件下葡萄主要品质和相关生理指标的影响.结果表明,储藏60d与对照相比,三种浓度的SO2处理均能在不同程度上降低贮藏过程中葡萄果实的腐烂率、脱粒率、果梗褐变和果穗失重率.延缓葡萄果实中可溶性固形物和维生素C的下降.使呼吸强度维持在较低水平.500μL/L和100μL/L的SO2熏蒸处理能减缓贮藏后期果实可滴定酸的下降,1000μL/L浓度SO2熏蒸处理使果实可滴定酸升高.500μL/L和100μL/L浓度SO2熏蒸处理贮藏的葡萄60d后,果肉中SO2残留量分别为8.31mg/kg和6.52mg/kg.均低于FDA安全标准(10mg/kg),而1000μL/L浓度SO2熏蒸处理使果肉中SO2残留量达到23.17mg/kg,超出FDA安全标准.     

气相色谱-质谱联用法检测香菇中香菇素的含量

建立测定香菇中香菇素的气相色谱-质谱联用检测方法。以乙腈提取样品,Florisil柱净化,使用气相色谱-质谱仪以选择离子监测模式进行分析测定。在设定色谱条件下,香菇素在1.0～20.0 mg/mL范围内线性良好;添加10.0、20.0、30.0 mg/kg香菇素溶液的平均回收率在86.61%～98.48%之间,相对标准偏差在2.92%～4.28%之间,检出限为0.10 mg/kg,定量限为0.25 mg/kg。本方法操作方便、重复性良好,为香菇中香菇素的定性和定量检测提供可靠的分析方法。     

GC-MS法测定学生用品中的邻苯二甲酸酯

建立了气相色谱-质谱仪同时测定学生用品中10种邻苯二甲酸酯的方法。以四氢呋喃为萃取剂,超声提取后,使用正己烷进行沉淀,内标法定量。DIBP、DBP、DPP、DHXP、BBP、DEHP、DCHP、DNOP在浓度0.4～20mg/L范围内的线性关系良好,检出限为5.0 mg/kg,DINP、DIDP在浓度2.0～100 mg/L范围内的线性关系良好,检出限为25 mg/kg。该方法平均回收率均在85.63%～110.61%范围内,相对标准偏差均小于5%。     

固相萃取-气相色谱法测定农产品中嘧霉胺的残留量

建立了青菜、大米、草莓、葡萄和西红柿等样品嘧霉胺残留量的SPE-GC测定方法。样品经乙腈提取,液-液分配和SPE净化,用气相色谱分法(NPD)检测器,外标法定量。实验结果:添加浓度在0.1～2.5mg/kg之间,测得其回收率为83.44%～108.82%之间,方法的检出限为0.05mg/L,同一样品中5次测定嘧霉胺残留量的相对标准偏差小于5%。     

气相色谱法测定黄酒中β-苯乙醇的含量

研究了以毛细管气相色谱法测定黄酒中β-苯乙醇的方法.用正己烷萃取黄酒样品中的β-苯乙醇,经旋转蒸发仪浓缩,采用TR-WAX(30 m× 0.32 mn i.d×0.25靘)气相色谱柱分离,氢火焰离子化检测器检测,并以保留时间定性和峰面积定量.方法的线性范围为0.5mg/L～50mg/L(r=0.9993),检测限0.2mg/L,相对标准偏差为1.02%(n=5),回收率为92.2%～105.9%(n=5).     

气相色谱法快速测定柑桔汁中残留杀扑磷

报道了一种气相色谱快速测定柑桔汁中残留杀扑磷的分析方法。样品以乙腈提取,经石英毛细管气相色谱柱DB-1701分离,GC-FPD检测,外标法定量。该方法的加标回收率为99.7%～115.2%,相对标准偏差为4.3%～6.8%,按25.0mL取样量计算,方法的最低检出限为0.01mg/L。     

A Rapid Method for Determining Allylisothiocyanate in Horseradish-Containing Products

A rapid method for determining allylisothiocyanate (AITC) in horseradish-containing products was developed. Headspace samples were analyzed by gas chromatography and the AITC peak identity was confirmed by mass spectrometry. The coefficient of variation was less than 4%. Recovery of added AITC from commercial ground horseradish products averaged 91% for six different samples. Recovery of added AITC from a tomato-based sauce containing horseradish oil averaged 94% for seven samples. The slopes of the standard curves for AITC were dependent upon the sample matrix with the slope for AITC in oil less than 5% of that for AITC in water.     

Release of Allyl Isothiocyanate from Mustard Seed Meal Powder

Allyl isothiocyanate (AITC) is a wide‐spectrum antimicrobial compound found in mustard seeds, produced when their tissues are disrupted. The formation of AITC in mustard seed is mediated by the myrosinase enzyme which catalyzes the release of volatile AITC from a glucosinolate—sinigrin. Since water is a substrate in the reaction, humidity from the air can be used to activate the release of AITC from mustard seed. In this study, defatted and partially defatted mustard seed meals were ground into powders with particle size ranging from 5 to 300 μm. The mustard seed meal powder (MSMP) samples were enclosed within hermetically sealed glass jars wherein the headspace air was adjusted to 85% or 100% relative humidity at 5, 20, or 35 °C. Data from gas chromatography analysis showed that AITC release rate and amount increased with increasing relative humidity and temperature. Moreover, the release rate can be manipulated by particle size and lipid content of the MSMP samples. The amount of AITC released ranged from 2 to 17 mg/g MSMP within 24 h under the experimental conditions tested. In view of the antimicrobial properties of AITC, the mustard meal powder may be used as a natural antimicrobial material for extending the shelf life of food products.     

超声波辅助萃取气相色谱法测定食品中风味成分异硫氰酸烯丙酯

结合超声波辅助萃取比较不同有机溶剂对食品中异硫氰酸烯丙酯(AITC)的提取效果,并对其含量进行气相色谱分析.结果发现:以甲醇作为萃取剂的萃取效果最佳.该方法的线性范围为0.4 g/L～2.0g/L,相关系数为0.9999,最低检出限为0.001 g/L,精密度RSD为1.57%,回收率为98.7%～102.7%.     

毛细管气相色谱法测定白酒中的甲醇、乙酸乙酯和杂醇油

建立了一种用毛细管气相色谱法测定白酒中甲醇、乙酸乙酯和杂醇油的方法,并对色谱条件进行了优化。样品加标回收率在91.7%～98.5%之间,相关系数在0.9954以上,相对标准偏差1.1%～3.1%。该方法简便、快速、准确、结果令人满意。     

Rat intestinal microbiota digest desulfosinigrin to form allyl cyanide and 1-cyano-2,3-epithiopropane

The ability of rat intestinal microbiota to digest sinigrin and desulfosinigrin was studied using high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). When sinigrin was incubated with rat intestinal microbiota, up to 64% of the initial amount of sinigrin was degraded during 12 h, yielding allyl isothiocyanate (AITC) as the major product along with a minor amount of allyl cyanide (ACN) and a trace amount of 1-cyano-2,3-epithiopropane (CETP), although the amount of ACN exceeded that of AITC after 12 h of incubation. In contrast, when desulfosinigrin was incubated with rat intestinal microbiota for 6 h, desulfosinigrin was digested up to 69% to form ACN and CETP as the major products instead of AITC. Whether the epithiospecifier protein (ESP) is involved in CETP formation in the rat intestinal microbiota-mediated degradation of desulfosinigrin remains to be established. However, only a trace amount of desulfosinigrin was detected during incubation of sinigrin with intestinal microbiota, although the intestinal microbiota had distinct sulfatase activity when p-nitrocatechol sulfate was used as the substrate. This observation suggested that the sulfatase of the rat intestinal microbiota has a very poor specificity toward sinigrin, which may be one reason for the formation of trace amounts of CETP during the intestinal microbiota-mediated digestion of sinigrin.     

A Capillary GC Determination of Cyclopropenoid Fatty Acids in Cottonseed Oils

A capillary gas chromatography (GC) method was studied for direct analysis for cyclopropenoid fatty acids (CPEFAs) as methyl esters. No thermal alterations were indicated in CPEFA methyl esters on a Supelcowax 10 or a DB-5 capillary column like other fatty acid methyl esters (FAMES), which obviated a second derivatization. GC conditions are described for a complete separation and quantitation of CPEFAs in cottonseed oils. CPEFAs of cottonseed oils from various refining steps were analyzed by the method. The reliability of the method was demonstrated with over 95% recoveries of CPEFA methyl esters diluted in corn oil FAMES at various levels as low as 0.017%.     

茶叶中杀螟丹残留的气相色谱分析方法研究

介绍了一种快速、灵敏、可靠的适用于茶叶样品中杀螟丹残留量的气相色谱分析方法。茶叶样品经过稀盐酸溶液提取,在碱性条件下提取液中的杀螟丹水解反应生成沙蚕毒素,经过乙醚萃取,液-液分配净化,用毛细管气相色谱法(FPD-S)测定沙蚕毒素的残留量。结果表明:样品添加回收率在76%～103%之间,检测结果为相对标准偏差均小于10%,方法的检测限为0.01mg/kg,符合农药残留分析的要求。该方法的可行性为茶叶中杀螟丹的残留分析提供了一种简便、可靠、准确的方法。     

顶空固相微萃取法快速测定苹果酒中的香味物质

以顶空固相微萃取法 (HeadSpaceSolid PhaseMicro Extractions,HS SPME)和气相色谱质谱 (GasChromatgraphy MassSpectrometry ,GC MS)联用 ,2 辛醇为内标 ,研究了萃取头、萃取时间、加盐质量浓度、萃取温度对苹果酒中香气物质萃取的影响 ,优化了分析条件 ,建立了快速测定苹果酒中香气物质的方法 .该方法在苹果酒中常见香气物质的质量浓度范围内有良好的线性关系 ,对常见香气物质的定量比较准确     

基质固相分散-气相色谱法测定胡萝卜中百菌清和拟除虫菊酯类农药

建立了毛细管气相色谱法同时分析胡萝卜中百菌清和5种拟除虫菊酯类农药的方法。样品以乙酸乙酯为洗脱剂经基质固相分散(matrix solid-phase dispersion,MSPD)提取和净化,DB-5毛细管柱分离,采用GC-μECD分析、外标法定量。样品加标回收率为80.5%～107.6%,相对标准偏差小于7%,方法检出限为0.003～0.006mg/kg。该方法简便、快速、灵敏、准确,符合蔬菜中百菌清和拟除虫菊酯类农药检测的要求。     

加速溶剂提取-凝胶渗透色谱净化-气相色谱测定咸鱼中的敌敌畏

建立咸鱼中敌敌畏残留的气相色谱分析方法。采用加速溶剂萃取(ASE)提取咸鱼样品中的敌敌畏,经凝胶渗透色谱(GPC)净化,浓缩定容后用GC-FPD 检测分析,外标法定量。样品添加水平为2.5 × 10-2mg/kg 和10.0 ×10-2mg/kg 时,敌敌畏的回收率在74.4%～96.8% 之间,方法检出限为5.0 × 10-4mg/kg。本方法准确、自动化程度高、净化效果好,满足残留分析要求。