芹菜中黄酮类物质的提取和测定

采用碱溶酸析法，成功地提取了芹菜中黄酮类物质。经HCl-镁粉反应和红外光谱鉴定，提取物为黄酮类物质。另外，利用分光光度法，以芦丁为标准对芹菜的叶和茎中的总黄酮分别进行了测定，其质量分数分别为10．19mg／g，3．064mg／g。同时讨论了时间及色素对测定方法的影响，结果表明，显色时间在40min内稳定，色素引起误差为5％。     

氢化物发生-原子荧光光谱法测定芹菜籽中的硒

本法采用湿法消解,氢化物发生-原子荧光光谱法测定芹菜籽中硒。研究了原子荧光光谱仪的参数和最佳试验条件,方法的线性方程为I=124.350C-21.041,相关系数r=0.9999,检出限为0.1007μg/L。结果表明,芹菜籽中硒的回收率在94.3%—111.1%之间。     

Identification and quantification of benzimidazole metabolites of thiophonate-methyl sprayed on celery cabbage using SiO2@NiO solid-phase extraction in combination with HPLC-MS/MS

Thiophonate-methyl(TPM) is one of fungicides and pesticides widely used in agriculture field.However,the residue of its benzimidazole(BZD) metabolites in related agricultural products poses a potential risk to consumers.In this paper,nickel oxide nanoparticle-deposited silica(SiO_2@NiO) composite was used for the selective enrichment and purification of TPM's BZD metabolites in celery cabbage sprayed with TPM.Meanwhile,high-performance liquid chromatography coupled with precursor ion scan-mass spectrometry(HPLC-PIS-MS) and high-resolution MS/MS analysis(HR-MS/MS) was utilized for their qualitative and quantitative analysis.Twenty-one potential TPM's BZD metabolites were found and four of them were identified.One metabolite was discovered for the first time.Besides,a robust and sensitive quantitative method was developed with good linearities(R^2> 0.9972) within a wide range of 10.00-1000 ng/g.The detection limits of three known TPM's metabolites were within the range of 3.20-4.90 ng/g.Relative standard deviations(RSDs) of intra-day and inter-day precisions were less than 18.3%,which showed perfect reproducibility.The method was successfully applied to monitoring TPM's BZD metabolites in celery cabbage sprayed with TPM and the concentration versus time curves of TPM's metabolites in celery cabbage were plotted.This method is expected to be used to monitor BZD residues in various fruits and vegetables.     

液相色谱/串联质谱法测定芹菜中甲拌磷及其代谢物残留

建立了芹菜中甲拌磷及其代谢物(甲拌磷亚砜和甲拌磷砜)残留的液相色谱/串联质谱检测方法。样品以乙腈提取,采用电喷雾正离子源(ESI+)和多重反应监测(MRM)模式测定,基质匹配标准曲线定量。结果表明:芹菜基质中甲拌磷、甲拌磷亚砜和甲拌磷砜在0.01~0.1mg/L范围内线性关系均较好(r0.995),方法检出限和定量限分别为0.42~1.10μg/kg和1.4~3.6μg/kg;在5、50和100μg/kg三个添加水平下,甲拌磷、甲拌磷亚砜和甲拌磷砜的回收率为71.9%~90.2%,相对标准偏差为5.8%~9.9%。该法简单、准确、快速、灵敏,符合法规残留限量监测要求。     

有机栽培芹菜和普通栽培芹菜的矿物元素与营养物质含量比较研究

采用电感耦合等离子体-原子发射光谱(ICP-AES)法对来自有机生产体系和常规生产体系芹菜的Ca,Mg,K,Zn,Fe,Mn等必需元素和Cu,Cd和Pb等重金属元素含量进行了测定,同时对水分含量、总可溶性固形物、可溶性总糖、维生素C等含量进行了测定,发现有机栽培芹菜中K和Zn的含量较普通栽培芹菜分别显著高出70.22%和47.93%,差异显著(α=0.05);两种芹菜中Ca,Mg,Fe的含量差异不显著;有机栽培芹菜中Mn的含量较普通栽培芹菜显著低47.24%;两种芹菜中有害重金属Cu,Pb,Cd的含量差异不显著,且含量低于国标中规定的蔬菜Cu,Pb,Cd的含量;有机栽培芹菜与普通栽培芹菜水分含量、可溶性固形物含量无显著性差异,而有机栽培芹菜可溶性糖含量高出55.04%,维生素C的含量高出118.18%,差异显著。通过研究两种芹菜营养成分和矿物元素含量的不同,为有机栽培与常规栽培蔬菜的品质和安全性比较提供了有价值的参考。     

Stereoisomeric flavor compounds LXXVII: 3-Butylhexahydrophthalides: Simultaneous enantioselective analysis,structure elucidation,and sensorial properties of the stereoisomers

Using heptakis-(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-β-cy-clodextrin as the chirul stationary phase in enantioselective gas chromatography, the simultaneous enantioselective analysis of all eight 3-butylhexahydrophthalide Stereoisomers was achieved. Fur-thermore, the odor characteristics and odor thresholds were investigated by enantioselective gas chromatography/olfactometry. Racemic standards were synthesized via hydrogenation and subsequent base catalyzed epimerization. Starting from racemic 3-butylphthalide. After separation by high performance liquid chromatography. Relative configurations of the pure diastereoisom-ers were determined by means of NOE-difference spectroscopy. The absolute configuration at C-3 was determined starting from (3S)-butylphthalide as an educt for hydrogenation and epimerization. Absolute configurations of all eight 3-butylhexahydrophtbalide stereoisomers are unambiguously concluded from the NOE-experi-ments in connection with the determination of the absolute configuration at C-3.     

悬浮液进样-火焰原子吸收光谱测定芹菜中的锌铁锰铜

不使用稳定剂,直接用蒸馏水制成芹菜样品的悬浮液,用SrCl2消除相关干扰,在磁力搅拌下进样,应用标准曲线法在同一溶液中利用空气——乙炔火焰原子吸收光谱法测定Zn、Fe、Mn、Cu等4种元素含量。结果表明,芹菜中含有丰富的Zn以及Fe、Mn、Cu。本文考察了方法的准确度和精密度。试验表明,在选定的条件下,芹菜中各元素间相互不干扰,可在同一份制备液中进行4种元素的分别测定。方法的加标回收率在90.0%~102.0%之间,相对标准偏差在0.21%~0.77%之间(n=3)。测定结果与高温灰化法一致,t检验表明两者无显著性差异。     

动态微波辅助顶空固相微萃取-气相色谱-质谱法测定芹菜叶中的化学成分

采用动态微波辅助顶空固相微萃取结合气相色谱-质谱法测定芹菜叶中的挥发性和半挥发性化学成分。对水蒸气蒸馏、顶空固相微萃取、微波辅助顶空固相微萃取、动态微波辅助顶空固相微萃取等4种不同的前处理方法进行了比较,通过气相色谱-质谱分析,分别鉴定出20,17,36,41种化学成分,主要化合物为α-月桂烯、柠檬烯、β-顺式罗勒烯、β-芹子烯和(Z)-3-己烯-1-醇等。结果表明:动态微波辅助顶空固相微萃取是一种简单、快速、易操作,无需净化步骤,消耗样品量少,对于沸点较高的半挥发性物质的萃取效果优于微波辅助顶空固相微萃取的方法,可用于分析各类植物中的挥发性和半挥发性化学成分。     

超声波法提取芹菜叶中多酚类物质

通过单因素试验确定了芹菜叶中多酚类物质较佳的超声波提取工艺条件为:300Hz超声波振荡,提取剂为85%乙醇溶液,料液比为0.8g/10mL,提取时间50min,提取温度40℃。通过分光光度法测定了芹菜叶中多酚类物质的含量为3.0%,即30mg/g。     

卷心菜和芹菜中的17种元素测定

采用微波消解法处理卷心菜和芹菜样品,并用ICP-AES法测定这两种蔬菜中的17种微量元素Ca,Mg,K,Na,P,Zn,Fe,Cu,Mn,Al,Se,Cr,Ni,Cd,As,Pb,Hg。结果表明,两种蔬菜中均含有丰富的矿物元素Ca,Mg,K,Na,P,芹菜中的矿物元素更高,也存在少量能调节人体生理机能的有益微量元素Zn、Fe、Mn、Al、Cu、Ni,除了卷心菜中Hg含量超标外,其它有害重金属元素均属国家食品安全卫生标准之内。