Analysis of Chlorogenic Acid in Herbal Medicines by Capillary Electrophoresis

Atpresent,thecommonlyusedmethodforanalyzingherbalmedicinesishighperformanceliquidchromatography(HPLC).However,theuseofHPLCisrestrictedformanyreasons.Themostseriousproblemisthatthechromatographiccolumniseasilycontaminated.ComparedwithHPLC,capillaryelectrophoresis(CE)ischaracterizedwithhighefficiency,rapidity,lowcostandmultiplemodestobechosen.Inaddition,thecapillarycanbeeasilyregenerated.SoCEisidealforanalyzing"dirty"samples,suchasChineseherbalmedicines.Infact,studiesintheareaarebecoming…     

Meso-四(对-磺基苯基)卟啉光度法测定螺旋藻中的痕量锌

在pH=4．5的乙酸-乙酸钠缓冲介质中，锌和meso-四-（对磺基苯基）卟啉生成1：l的黄色配合物，λmax=421nm，ε=4.34×105L·mol-1·cm-1。该法可不经分离直接测定螺旋藻中的锌,结果满意。     

高效液相色谱法测定强化食品中维生素C的含量

建立了强化食品(饮料、奶粉、含乳饮料、大米、果泥及果冻)中维生素C含量的高效液相色谱检测方法。优化了样品处理方法,在水浴控温和避光条件下处理样品,避免维生素C被氧化。选用Tech Mate C18–ST(250 mm×4.6 mm,5μm)反相色谱柱,以0.05 mol/L磷酸二氢钾缓冲溶液(p H 3)为流动相,流量为1.0m L/min,检测器为光电二极管阵列检测器,检测波长为266 nm。线性范围为0.2~100μg/m L,相关系数为0.999 6,果泥中维生素C的定量限为20 mg/kg,其它为100 mg/kg,加标回收率为82.2%~107%,测定结果的相对标准偏差为1.23%~6.86%(n=8)。该方法简单快速,其灵敏度、准确度和精密度均能满足强化食品中维生素C的检测要求。     

Syntheses,Structures, and Properties of the 3D Lanthanide Organic Frameworks with N‐Heterocyclic Polycarboxylic Acids

Four 3D lanthanide organic frameworks from potassium pyrazine‐2, 3, 5, 6‐tetracarboxylate (K₄pztc) or potassium pyridine‐2, 3, 5, 6‐tetracarboxylate (K₄pdtc), namely, {[KEu(pztc)(H₂O)₂] · H₂O}_n ( 1 ), {[KTb(pztc)(H₂O)₂] · 1.25H₂O}_n ( 2 ), {[KLn(pdtc)(H₂O)] · H₂O}_n [Ln = Gd ( 3 ), Ho ( 4 )], were synthesized by reaction of the corresponding lanthanide oxides with K₄pztc or K₄pdtc in presence of HCl under hydrothermal conditions, and characterized by elemental analysis, TGA, IR and fluorescence spectroscopy as well as X‐ray diffraction. In complexes 1 and 2 , the dodecadentate chelator pztc^4– links four Ln^III ions and four K^I ions. The coordination mode of the pztc^4– ligand is reported for the first time herein. Complexes 3 and 4 are isostructural with earlier reported Nd, Dy, Er complexes. Moreover, the Eu^III and Tb^III complexes exhibit the characteristic luminescence.     

Influence of axial coordination on the photophysical property of excited state of zinc porphyrin

The phenomenon that metalloporphyrins are coordinated to axial ligands is very common especially in green-plant and photosynthetic bacteria, where such coordination impacts a signifi-cant effect on both the primary charge separation in the reaction center and energy transfer in an-tenna systems[1]. In addition, it plays a key role in photodynamic therapy and medicine synthesis in a sense that some metalloporphyrins have been assembled by coordination bonds to anti-cancer drugs, enhancing the se…     

高效液相色谱/安培检测法测定蜂蜜中苯酚残留量

研究了用高效液相色谱 /安培检测法测定蜂蜜中苯酚残留量。考察了试验参数对测定结果的影响。在所选试验条件下 ,苯酚保留时间约为 12min ,检出限为 2 .0ng·g- 1。三组不同水平的加样回收率为 91.6 10 1.9% ,相对标准偏差 2 .812 .8%。测定结果满意     

毛细管区带电泳法分析头孢菌素类药物的纯度

摘要：提出了以pH9.20的20mmol/L硼酸缓冲溶液、pH6.86的20mmol/L磷酸缓冲溶液和pH2.05的50mmol/L磷酸缓冲溶液作为背景电解质分析9种头孢菌素类抗生素药物纯度的毛细管区带电泳方法。用内部归一化法定量,方法简单快速。讨论了方法的优点和局限性。     

测定麦芽糖转糖苷反应体系组成的高效液相色谱法

建立了分析低聚异麦芽糖组成的高效液相色谱法，采用Spherisorb-NH2色谱柱，示差折光检测器，乙腈－水（体积比70：30）为流动相，外标法定量测定；结果显示各糖质量浓度在0．1－10g/L范围内与峰面积呈良好线性关系，相关系数为0．999 0－0．999 7；应用法跟踪了pH5．0的柠檬酸－柠檬酸钠缓冲溶液中以α－葡萄糖转苷酶为催化剂在58℃温度下的麦芽糖转糖苷反应，分析了反应体系组成随时间的变化，得到了上述反应条件下麦芽糖最大限度地转化为低聚异麦芽糖的最佳反应时间为24h；该法快捷、简单、准确，可用于低聚异麦芽糖生产的质量控制。     

应用近红外技术测定黄豆粕中水分、蛋白质和粗脂肪

应用近红外分析仪（NIR）快速测定黄豆粕中水分、蛋白质和粗脂肪的含量,通过光谱扫描统计分析,分别找出测量黄豆粕水分、蛋白质、粗脂肪的波长及校准常数值,经数理统计分析结果表明：近红外法与常规水分测定法经典凯氏定氮法、索氏浸提法所测定的结果呈密切的线性相关,检测结果令人满意。     

整体柱在线净化-液相色谱-高分辨质谱法快速测定牛奶中15种糖皮质激素

将自制的在线固相萃取柱与液相色谱串联四极杆静电轨道离子阱质谱技术相结合,建立了快速测定牛奶中15种糖皮质激素类药物的新方法.样品采用乙腈均质提取2 min,经自制在线固相萃取小柱富集净化,在Waters CORTECS T3(150 mm ×2.1 mm,5μm)分析柱上实现良好分离,外标法定量.15种目标物质量浓度在0.10～100 ng/mL范围内线性关系良好,相关系数均大于0.99;在0.20,0.40,2.0μg/kg3个添加水平下,15种糖皮质激素的回收率在87.1％ ～ 116.0％之间,相对标准偏差(RSD)在3.2％～8.7％(n=6)之间;方法的检出限(LOD,S/N≥3)和定量限(LOQ,S/N≥1O)分别为0.10和0.20μg/kg.该法适用于大批量牛奶中糖皮质激素类药物的快速定性筛查和定量分析.