HPLC quantification of flavonoids and biflavonoids inCupressaceae leaves

Summary The aim of this investigation was to obtain qualitative and quantitative profiles of the flavonoid and biflavonoid composition of six cypress species—Cupressus funebris L.,Cupressus sempervirens L.,Cupressus glabra L.,Cupressus arizonica L.,Cupressus goveniana L., andCupressus lusitanica L. HPLC-diode-array detection (DAD), HPLC-MS, and HPTLC were used to identify the individual compounds. A chromatographic method was optimized for identification and quantification of the main flavonoid glycosides and biflavonoids. The flavonoids identified and calibrated were: rutin, quercetin glucoside, quercetin rhamnoside, and kaempferol 3-O-rhamnoside. The biflavonoids identified and calibrated were: cupressuflavone, amentoflavone, robustaflavone, hinokiflavone, methylrobustaflavone, methylamentoflavone, and dimethylcupressuflavone.     

GC-MS同时测定番石榴叶中的齐墩果酸和熊果酸

建立了测定番石榴叶中齐墩果酸和熊果酸的气相色谱-质谱（GC-MS）方法.以双（三甲硅烷）三氟乙酰胺（BSTFA）为衍生化试剂,将齐墩果酸和熊果酸制成三甲基硅烷衍生物后,在DB-5 MS毛细管柱上进行分离.柱升温程序为：柱初温100 ℃,恒温保持2 min, 以10 ℃/min的速度升温至300 ℃,保持14 min.通过与标准样品对照比较保留时间和质谱确认样品中齐墩果酸和熊果酸的色谱峰.以峰面积进行定量测定,齐墩果酸和熊果酸的线性范围分别为4.1～102 μg/mL和4.7～114 μg/mL,回收率分别为77.1%和89.4%,6次平行测定的相对标准偏差分别为3.7%和3.5%.     

Liquid chromatography/mass spectrometry-based metabolic profiling to elucidate chemical differences of tobacco leaves between Zimbabwe and China

An approach was developed for extracting and analyzing the chemical components of tobacco leaves based on solvent extraction and rapid & resolution liquid chromatography/quadrupole time-of-flight mass spectrometry analysis. Two solvents with different polarities were used to extract hydrophilic components and hydrophobic components, respectively, the combined analytical data can provide a "global" view of metabolites. Based on the evaluation of parallel samples, it was found that this approach provided good repeatability, accurate and reliable profiling data, and is suitable for the metabolomics study of tobacco leaves. In order to find the chemical component differences of tobacco leaves, 56 samples from Zimbabwe and China were analyzed using the developed method. The metabolite data were processed by multivariate statistic technique; an obvious group classification between Zimbabwe and China was observed, 14 significantly changed compounds were found, and 9 of them were identified.     

高效液相色谱法分离和测定白菜黑斑病菌中的腐败菌素B

建立了一种高效液相色谱分离和测定白菜黑斑病菌腐败菌素B的新方法。被真菌毒素感染的白菜病叶用乙酸乙酯萃取，用Nove-Pak C18柱进行分离，流动相为乙腈－水（1＋1），pH3.42，流速1．0mL/min，紫外检测波长206nm，腐败菌素B的分离时间是11．49min，检出限达到2．3ng，线性动态范围至少是3个数量级。本方法应用于白菜黑斑病叶样品的测定，并进行了回收率试验，腐败菌素B的5次测定值RSD≤1．2％，平均回收率≥97．1％。     

荧光法猝灭测定木槿叶中混合氨基酸的总量

在乙酸-乙酸钠缓冲介质中,氨基酸能猝灭壳聚糖-茚三酮体系荧光,基于此,对木槿叶中混合氨基酸进行测定,并对该方法的测定条件进行了讨论.线性范围为0.5～3.0 mmol/L,检出限为0.1 mmol/L.木槿叶干粉中游离氨基酸的质量分数为10.18%,相对标准偏差为1.3%,回收率为102.5%～94.3%.     

电感耦合等离子体原子发射光谱法测定杨树叶中铜锌铅镍

研究了电感耦合等离子体原子发射光谱法(ICP-AES)的仪器工作参数,溶液提升速率为2.4 mL.min-1,雾室压力为2.07×105Pa,观测高度为16 mm。用浓硝酸1 mL作样品的消化剂。用此方法测定杨树叶标准物质(GBW 07604)中铜、锌、铅、镍,相对误差在0.54%~9.3%之间,加标回收率在97.9%~101.0%之间。     

苎麻叶中绿原酸的分光光度法测定

探讨了采用分光光度法测定苎麻叶中绿原酸的含量的方法。12.5%的醋酸用量为0.1mL,7%尿素2.0mL,0.5%亚硝酸钠0.25mL,3min后加入5%氢氧化钠0.5mL,绿原酸与试剂形成鲜红色络合物,通过在510nm处测定溶液的吸光度确定绿原酸的含量。绿原酸浓度在0.01~0.12g/L范围内与吸光度值有良好的线性关系,回收率为95%~107%,相对标准偏差(RSD)为2.4%。该方法简便、快速。     

茶中茶多酚的高效液相色谱法分离分析

用改进的Ａｇａｒｗａｌ方法萃取不同种类茶叶和茶饮料中的茶多酚,建立了用高效液相色谱（ＨＰＬＣ）法对茶多酚进行分离分析方法。ＨＰＬＣ可有效分离ＧＴＰｓ主要组成成分ＥＣ、ＥＧＣ、ＥＣＧ和ＥＧＣＧ并精确定量,相对标准偏差小于５％。茶叶加工过程对ＧＴＰｓ含量有很大影响,绿茶总ＧＴＰｓ含量在６￣１５ｇ／１００ｇ干茶叶、乌龙茶总ＧＴＰｓ含量在５￣７ｇ／１００ｇ干茶叶,红茶总ＧＴＰｓ含量低于２ｇ／１００ｇ干茶叶     

The Constituents of the Leaves of Chamaecyparis Formosensis Matsum

Forty one terpenoidal compounds were isolated from the essential oil of Chamaecyparis formosensis Matsum. The dominant component is α-pinene. Other major components include β-pinene, 3-carene, α-terpineol, γ-muurolene, and kaurene.     

The Effects of Formulation on Imidacloprid Dissipation in Grapes and Vine Leaves and on Required Pre-Harvest Intervals under Lebanese Climatic Conditions

In this study, imidacloprid, a systemic insecticide, currently having a specified European Commission MRL value for vine leaves (2 mg kg⁻¹), was applied on a Lebanese vineyard under different commercial formulations: as a soluble liquid (SL) and water dispersible granules (WDG). In Lebanon, many commercial formulations of imidacloprid are subject to the same critical good agricultural practice (cGAP). It was, therefore, important to verify the variability in dissipation patterns according to matrix nature and formulation type. Random samplings of grapes and vine leaves were performed starting at 2 days until 18 days after treatment. Residue extractions were performed according to the QuEChERS method and the analytical determination using liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS). The SL formulation yielded significantly higher initial deposit than the WDG formulation on grapes and vine leaves. The formulation type did not significantly affect the dissipation rates; the estimated half-lives in grapes and vine leaves were 0.5 days for all imidacloprid formulations. No pre-harvest intervals were necessary on grapes. PHIs of 3.7 days for the SL formulation and 2.8 days for the WDG formulation were estimated on vine leaves. The results showed that the type of formulation and the morphological and physiological characteristics of the matrix had an effect on the initial deposits, and thus residue levels, but not on the dissipation patterns.