微型反应器-HPLC催化合成水杨酸甲酯的研究

选择水杨酸甲酯的催化合成反应为基础反应体系，以固体超强酸为催化剂，建立微型催化反应器与高效液相色谱的联用新技术，并对液固相催化酯化反应进行微反催化合成研究。使用ZrO₂-SiO₂/SO_^2-4催化剂制成微型催化反应器进行试验，建立微反-HPLC联用实验装置，考察了水杨酸的加入量以及反应温度对转化率的影响。并通过X-射线衍射、红外光谱和电子透镜等技术，对反应前后催化剂的晶相、酸性特征峰以及催化剂的形态形貌进行了表征。     

Effect of processing on sphingolipid content in soybean products

Soybeans are believed to be a rich source of sphingolipids, a class of polar lipids that has received attention for their possible cancer-inhibiting activities. The effect of processing on the sphingolipid content of various soybean products has not been determined. Glucosylceramide (GlcCer), the major sphingolipid type in soybeans, was measured in several processed soybean products to illustrate which product(s) GlcCer is partitioned into during processing and where it is lost. Whole soybeans were processed into full-fat flakes, from which crude oil was extracted. Crude oil was refined by conventional methods, and defatted soy flakes were further processed into alcohol-washed and acid-washed soy protein concentrates (SPC) and soy protein isolates (SPI) by laboratory-scale methods that simulated industrial practices. GlcCer was isolated from the samples by solvent extraction, solvent partition, and TLC and was quantified by HPLC. GlcCer remained mostly within the defatted soy flakes (91%) rather than in the oil (9%) after oil extraction. Only 52, 42, and 26% of GlcCer from defatted soy flakes was recovered in the acid-washed SPC, alcohol-washed SPC, and SPI products, respectively. All protein products had a similar GlcCer concentration of about 281 nmol/g (dry wt basis). The minor quantity of GlcCer in the crude oil was almost completely removed by water degumming.     

Chromatographic performance of monodisperse–macroporous particles produced by “modified seeded polymerization.” I: Effect of monomer/seed latex ratio

In this study, the monodisperse–macroporous particles produced by a relatively new polymerization protocol, the so‐called, “modified seeded polymerization,” were used as column‐packing material in the reversed phase chromatography (RPC) of proteins. The particles were synthesized in the form of styrene‐divinylbenzene copolymer approximately 7.5 μm in size. In the first stage of the synthesis, the monodisperse polystyrene particles 4.4 μm in size were obtained by dispersion polymerization and used as the “seed latex.” The seed particles were swollen by a low‐molecular‐weight organic agent and then by a monomer mixture. The monodisperse–macroporous particles were obtained by the polymerization of monomer mixture in the seed particles. In the proposed polymerization protocol, the number of successive swelling stages was reduced with respect to the present techniques by the use of sufficiently large particles with an appropriate average molecular weight as the seed latex. A series of particles with different porosity properties was obtained by varying the monomer/seed latex ratio. The separation behavior of HPLC columns including the produced particles as packing material was investigated in the RPC mode using a protein mixture including albumin, lysozyme, cytochrome c, and ribonuclease A. The chromatograms were obtained with different flow rates under an acetonitrile–water gradient. The theoretical plate number increased and chromatograms with higher resolutions were obtained with the particles produced by using a lower monomer/seed latex ratio. The separation ability of the column could be protected over a wide range of flow rates (i.e., 0.5–3 mL/min) with most of the materials tested. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 607–618, 2004     

Tocopherols in sea buckthorn (<Emphasis Type="Italic">Hippophaë rhamnoides</Emphasis> L.) berry oil

The free tocopherol content in whole berries of six sea buckthorn cultivars grown in northeastern Poland and Belorussia was determined with HPLC. The total free tocopherol content in oil from whole berries was 101.4–128.3 mg/100 g of oil. α-Tocopherol was the predominant tocopherol of sea buckthorn berries, and only traces of γ-tocopherol were detected in the oil. α- and δ-Tocopherols constituted 62.5–67.9% and 32.1–37.5% of total tocopherol, respectively. The total free tocopherol content in oil of sea buckthorn cv. Nadbaltycka increased during maturation from 40.4 to 109.8 mg/100 g of oil. Green berries contained a marked amount of γ-tocopherol, but its content rapidly declined to traces when the color of berries turned from green to olive-yellow.     

人胎盘泌乳素的提纯及裂解片断免疫学特性的研究

采用人胎盘泌乳素（hPL）-亲和层析和抗人血清抗体-亲和层析技术，从胎盘匀浆中提取hPL纯品，经圆盘电泳、免疫电泳及交叉试验证实为单一成分。溴化氰水解后的产物，以高效液相色谱分析。分离出7个肽链片断峰，分别用hPL和人生长激素（hGH）放免法检测其活性，其中第6肽链片断无hGH免疫活性，若用此片断制备特异抗体，可避免与hGH出现交叉反应。     

组织胺人免疫球蛋白组织胺含量测定方法的比较

目的 确定组织胺人免疫球蛋白组织胺测定的适宜方法。方法 通过对组织胺HPLC-柱后衍生物荧光分析法和酶标仪微孔板荧光分析法的比较,对样品制备、衍生物形成条件和检测参数进行了优化。结果HPLC-柱后衍生物生成温度为40℃,荧光检测器激发光波长为340 nm,发射光波长为425 nm,但组织胺信号峰前的倒峰使组织胺的峰形不完整且不对称;酶标仪微孔板荧光分析法测定的线性范围2.5～1000 ng,灵敏度1.25 ng,标准品测定在2.5～100 ng呈稳定性关系,样品测定的标准偏差小于5％。结论 酶标仪微孔荧光分析法可以用于游离组织胺含量测定。     

多杀菌素的高效液相色谱法测定

采用高效液相色谱法对Saccharpolyspora spinasa发酵液中多杀菌素含量进行测定。本方法的相对标准偏差为0．11％。变异系数为0．15%．线性相关系数为0．99916．平均回收率为96.94％。     

1,4-二巯基苏醇的高效液相色谱分析

采用C18 反相柱和紫外吸收检测器 ,以甲醇 +乙腈 +水作流动相 ,对 1,4 二巯基苏醇进行液相色谱分离 ,外标法定量。方法线性范围宽、精密度好、准确度高。     

超声辅助提取-固相萃取净化-高效液相色谱法测定沉积物中的2甲4氯残留

[目的]2甲4氯(MCPA)是农业生产和市政管理中一种广泛使用的除草剂,具有使用量大、生物毒性强、易迁移累积于水体沉积物等特点。针对其在沉积物中潜在环境风险大的现状,一种简单、有效的残留测定方法迫切需要建立。[方法]建立了一种C18为分离色谱柱,甲醇-水(体积比80:20)为流动相,PDA为检测器,检测波长为280 nm的MCPA高效液相检测法,并比较了不同提取方法和净化方法对检测的影响。[结果]对于提取方法,回收率:超声萃取2次>超声萃取1次>涡旋振荡萃取;对于净化方法,回收率:固相萃取净化法>QuEChERS法>未净化法。因此,应采用2次超声辅助提取-固相萃取净化作为前处理方法。所建立的方法在0.5~40 mg/L范围内线性良好,检出限为0.02 mg/kg,定量限为0.06 mg/kg;在0.08~0.8 mg/kg的添加水平范围内,回收率为85.12%~98.66%,相对标准偏差为2.86%~4.24%。[结论]该方法准确性高、稳定性好,适用于沉积物中MCPA的测定。     

40% 福&#183;多可湿性粉剂的高效液相色谱法的分析

介绍了采用YWG C18色谱柱,以甲醇 氨水(0.5%)=(50 50)溶液为流动相,用紫外检测器对试样中的多菌灵、福美双进行高效液相色谱分离的测定。福美双的标准偏差及变异系数分别为0.28和0.79%;多菌灵的标准偏差及变异系数为0.06和1.157%。