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排序方式: 共有6763条查询结果,搜索用时 15 毫秒
71.
采用反相离子对高效液相色谱法(HPLC)研究了C.I.Reactive Red 24 水解反应动力学.当染料溶液中羟基过量时, 可视为一级反应; -d[A]/dt=k[A].在pH=13时, ln(A0/A)与反应时间t呈线性关系; 95℃时的水解反应速率常数K(0.0599)比70℃时的k(0.0101)高约4倍; pH为13时, 反应速率常数K(5.99×10-2)比8.5时的k(4.8×10-3)高约11.5倍; pH值每升高1, 染料的水解速率相应提高1.5倍. 相似文献
72.
采用Hypersil-ODS2(4.6mm×250mm,5μm)色谱柱,乙腈-水(70∶30)流动相,242nm检测波长,建立了测定2-苯基-4-对氯苯基-1,5-苯并硫氮杂-α-(丁二酰亚胺基)-β-内酰胺的高效液相色谱法。该法线性范为0~0.1mg/mL,回归方程为A=1.63×108c-2.86×105,相关系数r=0.9994,相对标准偏差为0.33%(c=0.06mg/mL,n=5),检出限为0.08μg/mL。平均回收率在97.2%~102.4%之间。该法重现性好,灵敏度高,简单,快速,准确。 相似文献
73.
Elizabeth?Gutierrez Tong?WangEmail author 《Journal of the American Oil Chemists' Society》2004,81(10):971-977
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. 相似文献
74.
反相高效液相色谱法测定苯扎贝特的含量 总被引:2,自引:0,他引:2
研究了采用反相高效液相色谱测定苯扎贝特含量的方法 ,以磷酸盐缓冲液 (0 0 1mol/L的磷酸二氢钾用磷酸调节pH至 3 8) 甲醇 (4∶6 )为流动相 ,采用HypersilC18柱 (5 μm ,4 6mm× 15 0mm) ,检测波长为 2 30nm ,苯扎贝特在 0 0 114~0 114mg/mL范围内线性相关 ,回归方程为 :A =1 0 5× 10 4c(mg/mL) +2 70× 10 2 ,r =0 9997,此法简便、快速、结果准确可靠 相似文献
75.
高效液相色谱法在农药残留分析中的应用 总被引:4,自引:0,他引:4
朱正斌 《化学工业与工程技术》2004,25(6):51-53
介绍了高效液相色谱法在农药残留分析中的应用,列举了一些杀虫剂、除草剂、杀菌剂的分析方法,指出了高效液相色谱法在农药残留分析中发展方向。 相似文献
76.
77.
A review of the antioxidant potential of medicinal plant species 总被引:2,自引:0,他引:2
Duduku Krishnaiah Rosalam Sarbatly Rajesh Nithyanandam 《Food and Bioproducts Processing》2011,89(3):217-233
Some researchers suggest that two-thirds of the world's plant species have medicinal value; in particular, many medicinal plants have great antioxidant potential. Antioxidants reduce the oxidative stress in cells and are therefore useful in the treatment of many human diseases, including cancer, cardiovascular diseases and inflammatory diseases. This paper reviews the antioxidant potential of extracts from the stems, roots, bark, leaves, fruits and seeds of several important medicinal species. Synthetic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxylanisole (BHA) are currently used as food additives, and many plant species have similar antioxidant potentials as these synthetics. These species include Diospyros abyssinica, Pistacia lentiscus, Geranium sanguineum L., Sargentodoxa cuneata Rehd. Et Wils, Polyalthia cerasoides (Roxb.) Bedd, Crataeva nurvala Buch-Ham., Acacia auriculiformis A. Cunn, Teucrium polium L., Dracocephalum moldavica L., Urtica dioica L., Ficus microcarpa L. fil., Bidens pilosa Linn. Radiata, Leea indica, the Lamiaceae species, Uncaria tomentosa (Willd.) DC, Salvia officinalis L., Momordica Charantia L., Rheum ribes L., and Pelargonium endlicherianum. The literature reveals that these natural antioxidants represent a potentially side effect-free alternative to synthetic antioxidants in the food processing industry and for use in preventive medicine. 相似文献
78.
79.
建立了高效液相色谱-紫外-可见光检测器(HPLC/UV-Vis)同时测定化妆品中4种禁用着色剂的检测方法。化妆品样品以乙醇为溶剂进行萃取,然后以萃取液作为检测对象,采用C18反相色谱柱,以乙腈-0.5% H3PO4溶液为流动相进行梯度洗脱,用紫外-可见光检测器检测,定量检测波长530 nm。方法的平均回收率(n=8)为86%~100%,相对标准偏差(RSD)为3.68%~8.02%;碱性紫1、颜料橙5、苏丹蓝2、苏丹红IV的检出限分别为0.05,0.5,0.5,0.2μg/mL。 相似文献
80.
Mandana Bimakr Russly Abdul Rahman Farah Saleena TaipAli Ganjloo Liza Md Salleh Jinap SelamatAzizah Hamid I.S.M. Zaidul 《Food and Bioproducts Processing》2011,89(1):67-72
Different bioactive flavonoid compounds including catechin, epicatechin, rutin, myricetin, luteolin, apigenin and naringenin were obtained from spearmint (Mentha spicata L.) leaves by using conventional soxhlet extraction (CSE) and supercritical carbon dioxide (SC-CO2) extraction at different extraction schemes and parameters. The effect of different parameters such as temperature (40, 50 and 60 °C), pressure (100, 200 and 300 bar) and dynamic extraction time (30, 60 and 90 min) on the supercritical carbon dioxide (SC-CO2) extraction of spearmint flavonoids was investigated using full factorial arrangement in a completely randomized design (CRD). The extracts of spearmint leaves obtained by CSE and optimal SC-CO2 extraction conditions were further analyzed by high performance liquid chromatography (HPLC) to identify and quantify major bioactive flavonoid compounds profile. Comparable results were obtained by optimum SC-CO2 extraction condition (60 °C, 200 bar, 60 min) and 70% ethanol soxhlet extraction. As revealed by the results, soxhlet extraction had a higher crude extract yield (257.67 mg/g) comparing to the SC-CO2 extraction (60.57 mg/g). Supercritical carbon dioxide extract (optimum condition) was found to have more main flavonoid compounds (seven bioactive flavonoids) with high concentration comparing to the 70% ethanol soxhlet extraction (five bioactive flavonoids). Therefore, SC-CO2 extraction is considered as an alternative process compared to the CSE for obtaining the bioactive flavonoid compounds with high concentration from spearmint leaves. 相似文献