2,5—二氯苯胺防蛀剂的高效液相色谱分析

介绍了用高效液相色谱法快速测定新型防蛀剂２,５－二氯苯胺的方法,分离柱为ＨｙｐｅｒｓｉｌＣ１８柱,淋洗液为乙腈－水－醋酸（７０：２８：２）。该方法操作简便,分离条件较好,回收率大于９９％,变异系数为０．３５％。     

穿心莲内酯在超临界CO2萃取中晶体的形成与生长

用扫描电镜观察了超临界CO2结晶的穿心莲内酯颗粒微观形貌，并利用液相色谱进行纯度检测，阐述了穿心莲内酯在超临界CO2萃取中晶体在结晶板上成核、生长及分布。结果证实：超临界CO2在萃取釜中能同步萃取结晶穿心莲内酯，且在本实验条件下(压力低于25MPa)，晶体纯度在结晶板上呈梯度分布：从下到上，纯度越来越高。     

Stability and Antioxidant Activity of Beta Carotene in Conventional and High Oleic Canola Oil

Conventional canola oil (CO) and high oleic canola oil (HOCO) were stored under autoxidative and photooxidative conditions, β-carotene was added at 0 to 120 ppm. The oils were diluted in mobile phase and injected onto an HPLC column to track β-carotene changes over time. Peroxide values were followed to assess the oxidative stability of the oils. β-carotene was more stable in HOCO than in CO under autoxidative conditions, but no difference between oils was observed under photooxidative conditions. The HOCO was more stable against autoxidation, and CO was more stable against photo-oxidation. Antioxidant activity was shown by β-carotene in both oils, which contained natural tocopherols, during both autoxidative and photooxidative conditions.     

HPLC-TOFMS测定NG/TEGDN中的丙三醇二硝酸酯

应用高效液相色谱飞行时间质谱联用技术( HPLC-TOFMS)测定了丙三醇三硝酸酯(NG)/二缩三乙二醇二硝酸酯( TEGDN)混合硝酸酯中的杂质丙三醇二硝酸酯.色谱条件为Gemini5 μC-18色谱柱、55/45 (V/V)的甲醇/水流动相;质谱采集模式为电喷雾源负离子方式.结果表明:丙三醇二硝酸酯来源于NG,它存...     

用HPLC法测定对二异丙苯的一氢过氧化物和二氢过氧化物

二过氧化氢对二异丙苯是二异丙苯氧化法生产对苯二酚的重要中间产物。本文用HPLC半制备柱制得一过氧化氢对二异丙苯和二过氧化氢对二异丙苯纯品,用光谱法确定其结构,建立了正相高效液相色谱测定方法。     

ANALYSIS OF BEER CARBONYLS AT THE PART PER BILLION LEVEL BY COMBINED LIQUID CHROMATOGRAPHY AND HIGH PRESSURE LIQUID CHROMATOGRAPHY

Carbonyl compounds have been isolated from lager by low pressure distillation and recovered from the distillate as their 2,4-dinitrophenylhydrazone derivatives. The derivatives were subsequently separated into four monocarbonyl classes on a magnesia-silica gel column, and then each class resolved by HPLC. This technique has proved to be sensitive to carbonyls in lager at concentrations below 0·1 ppb and shows a high degree of resolution. So far, twelve methyl ketones, eleven saturated aldehydes and eight alkenals have been separated. The content of both fresh and aged lagers has been examined and changes in concentration discussed in relation to their reported taste thresholds.     

HPLC法测定药食两用植物刺梨中刺梨苷的含量

目的:建立药食两用植物刺梨中刺梨苷的含量测定方法。方法:刺梨以75%乙醇水浴回流提取,采用Pntulips TM BPC18(4.6 mm×250mm,5μm)色谱柱,乙腈-0.05%三氟醋酸溶液(27∶73)为流动相,流速1 ml/min,检测波长208 nm,柱温30℃,进样量为10μl。结果:刺梨苷在0.23~2.3μg范围内具有良好的线性关系,平均回收率为97.82%,RSD为2.44%(n=6)。结论:利用HPLC建立了药食两用植物刺梨中刺梨苷的含量测定方法,经方法学验证,该法简便、准确、稳定,为药食两用植物刺梨的合理开发利用提供质量评价依据。     

苯达松和2甲4氯复配除草剂的HPLC分析研究

采用C-8色谱柱和紫外检测器，对复配除草剂中的二种活性成分苯达松和2甲4氯的含量进HPLC测定，以外标法面积定量。苯达松和2甲4氯的变异系数分别为0.53％和0.87％，线性相关系数分别为0.9999和0.9997，平均回收率分别为102.10％和98.32％。方法用于实样测定，结果令人满意。     

Evaluation of Antioxidative Constituents from Thyme

The non-polar fraction of thyme was examined for the occurrence of phenolic components and their antioxidative activity. In addition to carvacrol ( II ) and thymol ( III ), p -cymene-2,3-diol (I ; 2,3-dihydroxy-4-isopropyl-1-methylbenzene) was isolated for the first time from thyme. The structure of I was elucidated using ¹H nuclear magnetic resonance (NMR), ¹³C NMR, and mass spectrometry. Antioxidative activity was investigated with the Rancimat method (100°C) and the Schaal test (60°C). Compound I exhibited the strongest antioxidative activity which was greater than that of α-tocopherol and butylated hydroxyanisole. Five thyme species were analysed by means of HPLC with electrochemical detection for the concentration of compounds I – III . The highest amounts of I – III were found in Thymus vulgaris L.     

用HPLC法测定干红葡萄酒中的酚类物质

建立了用HPLC测定干红葡萄酒中11种酚类物质的方法，该法具有定量准确，快速的特点，在实验条件下，各物质的含量与峰面积呈良好的线性关系，且回收率较高。