Analysis of Oleanolic Acid and Ursolic Acid,Potential Antifertility Agents in Moringa （Moringa oleifera） Seed

Oleanolic acid （OA） and ursolic acid （UA） are isomeric tritcrpenes that are difficult to separate chromatographically. Studies have indicated that both OA and UA have antifertility properties in several livestock species, suppressing attainment of puberty, gonad function and gamete production. Being able to determine the presence and quantity of the OA and UA in moringa and pawpaw seeds will allow for calculation of optimal inclusion levels of these acids in animal diets for antifertility-activity. The purpose of the study was thus to quantify the levels of OA and UA in Moringa and pawpaw seed powder by means of ultra-high performance liquid chromatography with electrospray ionization tandem mass spectrometry （UHPLC-ESI-MS/MS）. Only OA was detected in moringa seeds at a concentration level of 0.508 p.g/g ＋ 0.032 pg/g dry weight. UA and OA could not be detected in pawpaw seeds used in this study. The presence of OA in moringa seeds suggest that the seeds can be included in tilapia diets as a potential antifertility treatment to control precocious breeding in tilapia culture in small scale farming systems in Sub-Saharan Africa. Further studies are warranted to determine the levels of OA and UA composition in moringa seeds from other parts of the Sub-Saharan Africa （other than Zambia）.     

Analysis of Sugar Components of Fermented Rice Wine by Ion Chromatography

[Objective] The aim was to analyze sugar components in fermented rice wine by ion chromatography. [Method] The optimal condition for chromatography system of sugar analysis was selected by measuring sugars in fermented rice wine with ion chromatography and pulsed amperometric detection. [Result] The optimal measurement conditions were as follows： Leacheate （Leachate）, consisting of NaOH and CH3COONa, was eluted by gradient concentrations, with column temperature at 35 ℃ and flow rate at 0.4 ml/min. In the condition, sugars in rice wine were ana- lyzed and the results showed that the method is featured by low detection limit, good repetition and high recovery rate. [Conclusion] The research establishes and determines the approaches and optimum conditions for sugar analysis in rice wine by ion chromatography and pulsed amperometric detection, providing references for advancement of research on quality improvement of fermented rice wine.     

Detection of Tocopherol in Oilseed Rape （Brassica napus L.） Using Gas Chromatography with Flame Ionization Detector

The variation among Chinese genotypes of Brassica napus L.for seed tocopherols content and their analysis using gas chromatography has not been comprehensively reported till to date.In the present study,the tocopherol contents of four Chinese genotypes of Brassica napus L.,namely,Gaoyou 605,Zhejiang 619,Zheshuang 758,and Zheshuang 72,were evaluated using three modified sample preparation protocols(P1,P2,and P3) for tocopherol extraction.These methods were distinguished as follows.Protocol one(P1) included the evaporation of solvent after extraction without silylation.Protocol two(P2) followed the direct supernatant collection after overnight extraction without drying and silylation.Protocol three(P3) included trimethylsilylation with N,O-bis(trimethylsilyl) trifluoroacetamide.Genotypic comparison of tocopherol and its isoforms revealed that Gaoyou 605 was dominant over the other genotypes with(140.5±10.5),(316.2± 9.2),and(559.1±24.3) μg g-1 of seed meal α-,γ-,and total(T-) tocopherol,respectively,and a 0.44±0.04 α-to γ-tocopherol ratio.The comparison of the sample preparation protocols,on the other hand,suggests that P3 is the most suitable method for the tocopherol extraction from Brassica oilseeds and for the analysis of tocopherols using gas chromatography flame ionization detector(GC-FID).Trimethylsilylation is the key step differentiating P3 from P1 and P2.Variations detected in tocopherol contents among the Chinese rapeseed(B.napus) genotypes signify the need to quantify a wide range of rapeseed germplasm for seed tocopherol dynamics in short and crop improvement in long.     

加速溶剂提取-固相萃取净化-高效液相色谱法测定土壤中12种三嗪类除草剂的残留量

建立了加速溶剂（ASE）提取-固相萃取（SPE）净化-高效液相色谱（HPLC）同时检测土壤中12种三嗪类除草剂残留量的方法。土壤样品经过乙腈提取,氨基（NH2）固相萃取柱净化,高效液相色谱法-二极管阵列检测器（DAD）测定,外标法定量。12种三嗪类除草剂在0.02~2.00 mg·L-1范围内线性关系良好,相关系数在0.998 4~0.999 9之间,方法检出限在0.004~0.005 mg·kg-1之间。在0.02、0.04和0.10 mg·kg-1 3个浓度水平,平均添加回收率在75.2%~112.7     

茶树可溶性糖含量的HPLC-ELSD检测 及其与茶树抗寒性的相关分析

建立了茶树叶片中可溶性糖的高效液相色谱一蒸发光散射检测(HPLC-ELSD)的测定方法。以AgilentZorbax carbohydrate柱为分离柱,流动相为乙腈-水(75:25,V/V),流速1.0 mL.min-1,柱温30℃,上样量10μL。蒸发光散射检测器漂移管温度85℃,雾化器温度36℃。通过该方法测定越冬期间皖茶91、乌牛早、平阳特早和龙井43叶片中果糖、葡萄糖和蔗糖的含量变化。结果表明,越冬期间3种可溶性糖含量的变化幅度一致:皖茶91>龙井43>平阳特早>乌牛早。在茶树叶片中的含量均随着气温的降低呈现增长趋势,且具有较好的规律性。蔗糖作为茶树叶片中可溶性糖的主要成分,用HPLC-ELSD法可以方便、快速、准确的检测出来。因此低温胁迫下通过HPLC-ELSD法测定茶树叶片中蔗糖含量的变化,可作为鉴定茶树品种抗寒性的一种新方法。     

高效液相色谱法检测吡唑醚菌酯在烟叶和土壤中的残留及消解动态

研究建立了吡唑醚菌酯在烟叶和土壤中残留及消解动态的高效液相色谱分析方法。样品用乙腈提取,经固相萃取柱SPE-C18和SPE-PSA净化,高效液相色谱-二极管阵列检测器(HPLC-DAD)检测,外标法定量。结果表明:在0.01~2 mg/kg添加水平下,吡唑醚菌酯在烟叶和土壤中的平均回收率分别为97.5%~101.9%和93.4%~101.2%,相对标准偏差(RSD)分别为4.8%~6.8%和1.5%~10.5%。吡唑醚菌酯在烟叶和土壤中的定量限(LOQ)均为0.01 mg/kg。采用所建立的方法,测定了山东、湖南2年2地烟叶和土壤中吡唑醚菌酯的残留及消解动态。结果表明:吡唑醚菌酯在山东青岛烟叶和土壤中的半衰期分别为5.9~9.5 d和11.1~13.4 d;在湖南长沙烟叶和土壤中的半衰期分别为3.1~5.3 d和5.4~6.4 d。     

气相色谱法同时检测水果中氟吡菌酰胺、肟菌酯及其代谢物肟菌酸的残留量

采用气相色谱法建立了水果中氟吡菌酰胺、肟菌酯及其代谢物肟菌酸残留的分析方法。样品用乙腈匀浆提取,氯化钠和无水硫酸镁盐析后,经N-丙基乙二胺（PSA）分散固相萃取净化,气相色谱-电子捕获检测器（GC-ECD）检测。结果表明:在0.05~1 mg/kg添加水平下,氟吡菌酰胺、肟菌酯及其代谢物肟菌酸的平均回收率为79%~120%,相对标准偏差（RSD）为0.7%~16%。氟吡菌酰胺、肟菌酯及其代谢物肟菌酸在不同水果样品中的检出限（LOD）分别为0.01、0.015和0.01 mg/kg,定量限（LOQ）均为0.05 mg/kg。该方法快速、简单和稳定,可以满足水果中氟吡菌酰胺、肟菌酯及其代谢物肟菌酸残留量的检测要求。     

玉米中氯虫苯甲酰胺残留的超高效液相

研究建立了快速检测玉米中氯虫苯甲酰胺残留的超高效液相色谱(UPLC)分析方法。样品用乙腈-二氯甲烷[V(乙腈)∶V(二氯甲烷)=20∶80]提取,经N-丙基乙二胺(PSA)分散固相萃取剂净化,UPLC分离,二极管阵列检测器于254 nm处检测,外标法定量。结果表明:当添加水平为0.02~1 mg/kg时,平均回收率为81% ~91%,相对标准偏差(RSD)为6.2% ~14.0%;最小检出量(LOD)为 0.02 ng,最低检测浓度(LOQ)为0.02 mg/kg。方法的灵敏度、准确度及精密度均符合农药残留分析要求,适用于玉米中氯虫苯甲酰胺的残留分析。     

Air Drying Affects Extractable Sulfate in Soils of Variable Charge: Test of Two Extraction and Two Quantification Methods

Abstract

Fertilizer recommendations need to be based on reliable soil sulfate determinations. Airdrying samples changes irreversibly many properties of soils with variable charge and might affect the extractable sulfate. In this study, sulfate extracted from air‐dry and field‐moist samples was compared. Two extracting solutions [water and 00.1 M Ca(H₂PO₄) ₂] and two quantification methods (turbidimetry and ion chromatography) were assayed on A and B horizon samples of five Humic Acrisols from southeast Mexico. Air drying increased water‐extractable sulfate in Ah horizons, whereas in Bt horizons, it increased the 00.1 M Ca(H₂PO₄)₂‐extractable sulfate. Airdrying increased dissolved organic carbon contents in all samples and increased soil acidity and oxalate extractable iron in 70 and 60% of the samples, respectively. Results showed larger coefficients of variation in air‐dried samples. Turbidimetry resulted less sensible than ion chromatography. To enhance sensitivity and reproducibility, particularly organic soil samples should be analyzed field‐moist and by ion chromatography.     

Phytate Quantification using HPIC in the Presence of Iron and Aluminum

Phytate is an organic form of P that is difficult to analyze in complex matrices. To test if high concentrations of aluminum (Al) and iron (Fe) hinder accurate quantification of phytate in dairy manure and broiler litter when measured by high-performance ion chromatography (HPIC), researchers spiked dairy manure and broiler litter samples with Al, Fe, and phytate. Samples were alkaline extracted, acidified, and filtered, and then phytate spike recovery was analyzed with HPIC. High concentrations of Fe did not hinder phytate recovery in manure or litter samples. While phytate recovery was complete at typical manure and litter Al concentrations, high concentrations of Al inhibited phytate recovery in litter samples and in some manure samples. Overall, alkaline extraction of dairy manure and broiler litter and analysis with HPIC proved to be relatively accurate, fast, and cheap within normal Al and Fe ranges, compared to the commonly used nuclear magnetic resonance (NMR) method.