共查询到18条相似文献,搜索用时 125 毫秒
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苯酚-硫酸分光光度法测定玉竹中多糖含量 总被引:2,自引:0,他引:2
采用苯酚-硫酸分光光度法测定湘玉竹中的多糖含量,检测波长为490 nm,方法的线性范围为0~0.12mg/mL,线性回归方程为A=0.397 6m 0.033 8,相关系数r=0.999 4。用该方法对湘玉竹样品测定,并进行加标回收试验,回收率为104.2%~106.9%,相对标准偏差为1.44%(n=5)。 相似文献
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刘慧香李启艳牛水蛟刘莹崔玉花于海英 《化学分析计量》2023,(1):17-20
建立分光光度法测定玉竹药材中玉竹多糖含量。玉竹药材经加热回流提取,多糖经80%乙醇溶液沉淀12h,采用苯酚-硫酸法进行比色测定。葡萄糖的质量在0~120μg范围内与490 nm波长处的吸光度成正比,线性回归方程为y=0.006 42x-0.007 53,相关系数为0.999 6,检出限为0.91μg。显色后溶液在6 h内保持稳定,样品加标回收率为95.9%~98.6%,平行测定结果的相对标准偏差为1.13%(n=6)。该方法可用于玉竹药材中多糖含量的测定。 相似文献
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分别建立了测定补血是胶囊中Fe^2 和总铁(Fe)含量的分光光度法.方法灵敏、简便.并以Fe^2 、总铁(Fe)含量和Fe^2 /Fe来控制本品的质量. 相似文献
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对归芪补血胶囊中黄芪甲甙与微量元素的含量进行了测定。结果显示 ,5批样品黄芪甲甙平均含量为 1 1 67× 1 0 -3 ,Mg、Ca、Fe、Mn等元素含量较高。可见此法简便准确 ,结果满意 ,可用于本品的质量控制 相似文献
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杏鲍菇多糖的提取及含量测定 总被引:4,自引:0,他引:4
采用苯酚-硫酸分光光度法对杏鲍菇中多糖含量进行了测定。测定波长485 nm,多糖换算因子f=1.57,在5.00~70.00μg/mL范围内吸光度与被测物含量呈良好的线性关系,相关系数r=0.999 8,方法的回收率在98.6%~102.3%之间,相对标准偏差RSD在2.01%~2.94%之间。测定结果表明,杏鲍菇中含有丰富的多糖。该法简便、准确、重现性好,可作为杏鲍菇多糖含量的测定方法。 相似文献
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一些土壤和有机肥中氨基酸测定方法研究 总被引:2,自引:0,他引:2
一些土壤和有机肥中氨基酸测定方法研究袁吕江,熊凤麒,王正银(西南农业大学中心实验室重庆630716)(西南农业大学土化系重庆630716)关键词液相色谱法,氨基酸,土壤,有机肥1前言我国耕作土含氮量为0.4~3.8g/kg[1],其中90%~98%为... 相似文献
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天山花楸果实中微量元素及氨基酸的检测分析 总被引:1,自引:0,他引:1
为探讨天山花楸果实中微量元素与药理学的相互关系,采用原子吸收分光光度仪和氨基酸自动分析仪分别测定了花楸果实中8种微量元素及17种氨基酸。结果表明,天山花楸果实中含有比较丰富的人体必需氨基酸及微量元素,它与天山花楸的临床保健作用有一定的相关性,具有很高的开发价值。 相似文献
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Patcharee Ngamviriyavong Paweena Uppanan Wanida Janvikul 《Macromolecular Symposia》2008,264(1):135-139
Amino acid modified chitooligosaccharides were synthesized by the new synthetic route. The chloroacetyl-chitooliogosaccharide intermediates were prepared under a mild condition via a reaction between chitooligosaccharide (COS) and chloroacetic anhydride. The intermediates were subsequently reacted with a variety of amino acids, e.g., glycine, aspartic acid, alanine, arginine, and serine, under a basic condition, yielding amino acid modified COS products. The degree of chloroacetylation was calculated based on new 1H NMR absorption peaks at 3.80 and 3.94 ppm, corresponding to NH CO CH2 Cl and O CO CH2 Cl, respectively. The degrees of chloroacetylation determined were 0.40, 0.44, 0.62, and 0.93 when the mole ratios of chloroacetic anhydride to COS were 0.5, 1, 2, and 4, respectively. The chemical structures of the COS derivatives were also determined using 1H NMR spectroscopy. The biological properties of the derivatives were evaluated. Cytotoxicity of the derivatives was assessed by a direct contact, using L929 cells. An MTT assay was a method of choice to evaluate the efficacy of the derivatives to enhance the proliferation of L929 cells. 相似文献
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Fmoc保护氨基酸与Wang树脂的缩合反应 总被引:1,自引:0,他引:1
研究了保护氨基酸、Wang 树脂取代度、树脂粒度、搅拌方式对Fmoc-氨基酸-Wang树脂连接效率的影响. 结果表明, 保护氨基酸分子量的大小会因产生不同的位阻而影响缩合反应的效率, 分子量越小缩合效率越高; Wang树脂的取代度较高时, 已缩合的氨基酸给后续保护氨基酸的缩合形成阻碍, 使缩合效率降低; 粒径较小和搅拌较好时, 对保护氨基酸的粒内外扩散有利, 可提高反应速度和缩合效率. 相似文献
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In this study, stoichiometric protonation constants of L-tyrosine, L-cysteine, L-tryptophane, L-lysine, and L-histidine, and
their methyl and ethyl esters in water and ethanol–water mixtures of 30, 50, and 70% ethanol (v/v), were determined potentiometrically
using a combined pH electrode system calibrated as the concentration of hydrogen ion. Titrations were performed at 25∘C and the ionic strength of the medium was maintained at 0.10 mol⋅L−1 using sodium chloride. Protonation constants were calculated by using the BEST computer program. The effect of solvent composition
on the protonation constants is discussed. The log10 K2 values of esters generally decreased with increasing ethanol content. However, the log10 K1 values of the esters of L-tyrosine, L-cysteine, and L-tryptophane were found to increase with increasing ethanol content
in contrast those of L-lysine and L-histidine esters. 相似文献