小波变换分光光度法同时测定复方芦丁片中芦丁和维生素C

建立了同时测定复方芦丁片中芦丁和维生素C含量的计算分光光度法--小波变换分光光度法.对芦丁和维生素C的重叠吸收光谱进行连续小波变换,分别提取只与芦丁和维生素C有关的特征小波变换系数,由特征小波变换系数值和浓度建立的线性回归方程,可以准确地测定复方芦丁片中芦丁和维生素C的含量.芦丁和维生素C的线性范围分别为0～25 mg·L-1和0～15 mg·L-1,对3个模拟试样作回收率和精密度试验,回收率在98.1%～102.0%之间,RSD值均小于等于0.9%.     

微柱高效液相色谱法测定苦荞中芦丁和槲皮素

研究了用微柱高效液相色谱法测定苦荞中芦丁和槲皮素的方法。苦荞中的芦丁和槲皮素用90%甲醇加热回流提取,以Waters XterraTMRP18(1.0 mm×50 mm,2.5μm)色谱柱为固定相,1%的乙酸和甲醇为流动相,在该色谱条件下,苦荞中芦丁和槲皮素在2.0 min内可达到基线分离,用紫外二极管矩阵检测器检测,方法用于4种苦荞试样中芦丁和槲皮素的测定,分析结果的RSD在0.51%~1.20%之间,回收率在98%~102%间。     

槐花和槐米中芦丁和槲皮素的毛细管电泳分析

采用β-环糊精修饰区带毛细管电泳-内标定量法分析槐花和槐米中芦丁和槲皮素。在优化的条件下,芦丁和槲皮素在7min内得到基线分离。芦丁和槲皮素线性范围分别为1-200μg／mL、0.4-100μg／mL,检出限分别为0.3μg／mL、0.1μg／mL,相对标准偏差分别为4．4％、2．6％。     

7,4’-O-二苄基槲皮素的合成

以芦丁和溴化苄为原料,经选择性苄基化和酸水解去芦丁糖基反应合成了7,4’-O-二苄基槲皮素,总收率57.6%,其结构经1H NMR和IR确证。     

银掺杂聚L-精氨酸修饰电极同时测定芦丁和抗坏血酸

用循环伏安法制备银掺杂聚L-精氨酸修饰玻碳电极(Ag-PA/GCE),研究了芦丁和抗坏血酸在该修饰电极上的电化学行为,建立了芦丁和抗坏血酸同时测定的新方法。在pH=2.5的磷酸盐缓冲溶液(PBS)中,于140mV·s-1的扫速下,芦丁产生一对氧化还原峰,其氧化峰电位为0.552V,还原峰电位为0.491V;抗坏血酸产生一个氧化峰,峰电位为0.281V。芦丁和抗坏血酸的△Epa=0.271V,用氧化峰不需分离可直接对芦丁和抗坏血酸进行同时测定,在最佳条件下,芦丁和抗坏血酸的线性范围分别5.0×10-7~2.0×10-5 mol·L-1和2.5×10-5~5.0×10-3 mol·L-1,检出限分别为1.0×10-7 mol·L-1和1.0×10-5 mol·L-1。方法可用于复方芦丁片中芦丁和抗坏血酸的同时测定。     

偏最小二乘-分光光度法同时测定福美锌和代森锰农药残留量

利用紫外可见分光光度法研究了农药福美锌和代森锰与苯基荧光酮的相互作用,发现反应后的产物分别在波长为551和554 nm处最大有吸收,但光谱严重重叠.实验采集了450～700 nm波长范围吸光度数据,并对该数据进行一阶求导后用偏最小二乘法处理,据此建立了偏最小二乘-分光光度法同时测定福美锌和代森锰两种农药的新方法.福美锌和代森锰的线性范围分别为0.3～6.0和0.2～3.5 μg/mL;检出限分别为0.22和0.13 μg/mL.混合样品分析无需分离,方法简单、快速.用于水果、大米和自来水等实际样品测定.     

人工神经网络紫外光度法同时测定甲基苯甲醛的三种同分异构体及其与偏最小二乘法的比较

同分异构体的同时测定一直是分析化学领域的热点和难点问题,本文将化学计量学中的多元校正方法,如偏最小二乘法和人工神经网络法与紫外分光光度法相结合,同时测定了紫外吸收光谱严重重叠的甲基苯甲醛的三种同分异构体混合体系中各组分的含量。确定了测定的最佳波长范围为230～304 nm;测得48个混合标样的吸光度值用于建立模型,其中,邻、间、对甲基苯甲醛的浓度范围分别为6.0～15.0、7.0～16.0和8.0～19.0 μg·mL-1。7个模拟样品作为监测集用于检验所建立模型的预测性能。本文还讨论了三种组分浓度比例对所建立模型预测性能的影响并确定了可以准确测定的浓度比例范围。所建立的方法用于模拟样品的测定,其回收率在84.00%与109.60%之间。与偏最小二乘法的测定结果比较,经成对t检验表明,两种方法对邻、间甲基苯甲醛测定结果无显著性差异;而对甲基苯甲醛的测定,人工神经网络法的测定结果优于偏最小二乘法。     

偏最小二乘法用于荧光光度法同时测定铈,镨,铽

本文将偏最小二乘法(PLS)用于荧光光度法同时测定铈、镨、铽。对荧光光度法的测定条件及PLS法中系列校准样品的实验设计及测量波长点的选择等进行了试验和讨论。所建立的方法用于天然混合稀土氧化物中铈、镨、铽的测定,获得较满意的结果     

山楂果和桑枝提取物中总黄酮含量的Fe(phen)2+3探针共振瑞利散射法测定

在pH值约为8.0的BR缓冲介质中,桑色素、槲皮素和芦丁等黄酮类物质能与Fe(phen)2+3反应形成离子缔合物,此时将引起共振瑞利散射(RRS)显著增强,最大RRS波长均位于310 nm. 在一定范围内散射强度(ΔI)与黄酮类物质的浓度成正比,据此可以建立用Fe(phen)2+3测定某些黄酮类物质的新RRS法. 对桑色素、槲皮素和芦丁的检出限(3σ/K)分别为1.25×10-7 mol/L(37.74 μg/L),1.80×10-7 mol/L(54.42 μg/L),2.72×10-7 mol/L(167.30 μg/L). 研究了反应的适宜条件和影响因素,考察了共存物质的影响. 结果表明,方法有较好的选择性.分别以芦丁和桑色素为对照品测定了中药材山楂果和桑枝中的总黄酮含量,对反应机理进行了初步探讨.     

同时测定铜、镍、锌的非线性偏最小二乘分光光度法

建立了以1－[5-溴－2吡啶偶氮]－2,7－萘二酚（5－Br-PADN)为显色剂,TritonX-100为增溶增敏剂,用非线性偏最小二乘（NLPLS）－分光光度法同时测定Cu^ 、Ni^2 、Zn^2 的方法。用迭代偏最小二乘法（IPLS）选择测定波长,用自编原MATLAB计算机程序进行处理。结果表明,该法不仅克服了三组分之间相互干扰,而且较好地解决了非线性问题,所拟方法用人工样品的分析,准确度较好,结果令人满意。     

流动注射化学发光法测定槐米中槲皮素

在碱性溶液中槲皮素对过氧化氢氧化鲁米诺而产生的化学发光(CL)具有很强的抑制作用,且其CL强度的减弱程度与槲皮素浓度之间在一定的范围内呈线性关系。据此,并结合应用流动注射(FI)技术,提出了FI-CL测定槐米中槲皮素含量的方法。反应体系中所用试剂的最佳浓度为:①cH2O2=0.2mol.L-1;②c鲁米诺=8.5×10-4mol.L-1;③cNaOH=0.01mol.L-1。对槲皮素测定的线性范围为2.65×10-6～5.31×10-4mol.L-1之间,其检出限(3s/k)为9.26×10-7mol.L-1。用4×10-4mol.L-1槲皮素标准溶液进行精密度试验,测得相对标准偏差(n=11)为3.0%。分析试样时,先从槐米在pH 8～9的碱性溶液中提取芦丁,然后在微酸性(pH 5)溶液中使芦丁水解得到槲皮素粗品。将此粗品经反复重结晶得到槲皮素纯品,溶于乙醇(40+60)溶液中制成溶液,用于FI-CL分析。     

Development and Validation of an SPE-LC Method for the Simultaneous Determination of trans-Resveratrol and Selected Flavonoids in Wine

A simple LC method has been developed for the simultaneous determination of the flavonols rutin, myricetin, quercetin, kaempferol and the stilbene, trans-resveratrol, in wines. Sample clean-up was performed with polymeric Nexus ABS ELUT cartridges. The polyphenols were separated in less than 25 min using gradient elution and UV detection at 320 nm. Average recoveries of the analytes from spiked wine ranged from 82.2 to 117.6% and the detection limits, based on spiked extracted synthetic wine, ranged from 0.02 to 0.2 mgL^?1. The method was applied to the analysis of Greek wines.     

High-Performance Liquid Chromatographic Method for the Simultaneous Determination of Four Flavonols in Food Supplements and Pharmaceutical Formulations

A method using high-performance liquid chromatography with diode array detection (HPLC-DAD) as a powerful separation technique has been developed for the simultaneous determination of the four flavonols rutin, quercetin, kaempferol and isorhamnetin in food supplements and pharmaceutical formulations. The chromatographic separation was achieved in 36?min using a Symmetry C₁₈ column (250?×?3?mm; 5?µm) as the stationary phase and a mixture of methanol, acetonitrile, and pH 2.5 aqueous acetic acid as the mobile phase in gradient elution mode. The analytical wavelengths were 256?nm for rutin, quercetin and isorhamnetin, and 368?nm for kaempferol. An ultrasound-assisted extraction protocol was performed using methanol as solvent. The detection and quantification limits were lower than 0.03?µg mL^?1 and 0.08?µg mL^?1, respectively. The inter-day and intra-day precisions were less than 4.8 and 5.1%, respectively, and the average recoveries were in the range from 96 to 107%. The method was applied for the determination of the studied flavonols in food supplements and pharmaceutical preparations. The satisfactory recovery values demonstrate the potential of the developed method for the determination of the analytes in these samples. In addition, the method is suitable for routine quality control due its ease of operation.     

混合线性分析-分光光度法同时测定微量铁和铝

研究将混合线性分析（hybrid linear analysis,HLA）用于光谱分辨同时光度测定Fe^3 和Al^3 。在碱性条件下,Fe^3 和Al^3 与水杨基荧光酮生成光谱相互重叠的有色络合物,其浓度在0－320μ/L Fe^3 和0－160μg/L Al^3 范围内与吸光度呈良好线性关系。在550nm－630nm内取41个波长测量7组标准混合溶液的吸光度作为校正集,用最小二乘法求得的系数矢量作为各组分的纯光谱。以HLA法进行数据处理,在Fe^3 ：Al^3 浓度为10：1－1：8范围内测定回收率为93.3%-107.5%。将本法与偏最小二乘法（PLS）法进行了比较,本法获得了较好的准确度和精密度。     

偏最小二乘紫外分光光度法同时测定丁烯二酸的顺反异构体

将偏最小二乘法用于紫外分光光度分析,在pH=1.4的磷酸溶液中,同时测定了丁烯二酸的顺、反异构体。确定了测定的最佳波长范围为190～268nm;测得23个混合标样的吸光度值用于建立模型,顺、反丁烯二酸的浓度范围为3.0～14.0mg/L和1.0～13.0mg/L。所建立的测定二者模型的相关系数分别为0.9951和0.9983;平均回收率分别为100.8%和100.7%;均方根误差(RMSE)分别为0.3667和0.2233;预测相对误差(REP)分别为5.05%和3.49%。对3个批次反丁烯二酸样品的测定结果与高效液相色谱法的测定结果进行比较,经成对t检验表明,两种方法的测定结果无显著性差异。     

吸收光谱法同时检测食品中的苯甲酸钠与山梨酸钾

利用苯甲酸钠和山梨酸钾的紫外吸收光谱特性,设计了正交试验,结合偏最小二乘变量筛选法,获得变量数少、相关系数高、预报准确性好、能同时对苯甲酸钠和山梨酸钾进行浓度预报的模型,并应用于饮料、蜜饯、糕点和调色酒样品中苯甲酸钠和山梨酸钾的检测。样品平行测定结果的相对标准偏差均小于10%,方法的加标回收率为82%～107%,苯甲酸钠和山梨酸钾的检测范围分别为0.1～16.0 mg.L-1和0.1～6.0 mg.L-1,检出限分别为0.05 mg.L-1和0.01 mg.L-1。样品的检测结果与国标法的检测结果相吻合。     

Comparison of UV derivative-spectrophotometry and partial least-squares (PLS-1) calibration for determination of methotrexate and leucovorin in biological fluids

Binary mixtures of methotrexate (MTX) and leucovorin (LV) have been resolved by application of first-derivative spectrophotometry and partial least squares calibration (PLS-1). By measuring the first-derivative signals of MTX and LV at 354 and 300 nm, respectively, simultaneous determination was possible. The mean recoveries for urine samples were 91 and 96% for MTX and LV, respectively. Partial least squares (PLS-1) multivariate calibration has been applied to the determination of these compounds in serum and in urine without pretreatment of the samples. The absorption spectra of serum or urine samples spiked with methotrexate and/or leucovorin, were used to optimize the calibration matrixes by the PLS-1 method. The sensitivity and selectivity of the proposed procedures were calculated. Mean recoveries were 101 and 97% for MTX and LV, respectively, for serum samples, and 101 and 98% for MTX and LV, respectively, for urine samples.     

高效液相色谱法测定不同产地枇杷叶中的3种黄酮类成分

建立了高效液相色谱同时测定枇杷叶中3种黄酮类成分的分析方法。该方法分析了不同产地枇杷叶中芦丁、槲皮素和山柰酚的含量差异。枇杷叶粉末用甲醇超声提取后,加盐酸回流,制备样品测试液。采用Diamonsil C18色谱柱（250 mm×4.6 mm,5 μm）,以0.4%（v/v）磷酸水溶液-乙腈为流动相,梯度洗脱。分别对7个不同产地的枇杷叶样品中的芦丁、槲皮素和山柰酚进行测定。结果表明,芦丁、槲皮素、山柰酚在各自的质量浓度范围内线性关系良好（r>0.99）,加标回收率分别为96.33%、95.81%和95.80%,RSD分别为6.48%、0.90%和3.02%。该方法操作简单、分离度好、重复性高。不同产地枇杷叶中3种黄酮类成分的含量存在差异,其中芦丁的差异最大,而山柰酚的含量最稳定且在不同产地样品中均可检出,或可用作枇杷叶药材质量控制的标志成分。     

Simultaneous Determination of Quercetin and Luteolin in Dried Flowers by Multivariate HPLC-ECD Calibration

Two calibration models, partial least squares (PLS) and principal component regression (PCR), were applied to the simultaneous determination of quercetin and luteolin by high performance liquid chromatography (HPLC) with electrochemical detection (ECD). The proposed methods were successfully applied to the analysis of dried flower samples. It was found that the relative standard errors of prediction (RSEP) for the validation set of PLS of quercetin and luteolin was 1.31 and 2.23%, and the RSEP of PCR was found to be 3.56 and 4.32%, respectively. Several dried flower samples were analysed and the recoveries were in the range of 95.9–103.3%.     

硅掺杂碳量子点荧光猝灭法测定水样中铜(Ⅱ)

3-氨丙基三甲氧基硅烷(APTMS)与戊二醛(GA)混合前驱物合成的硅掺杂碳量子点(SDCQDs),其最大吸收、激发和发射波长分别为259,245,395 nm,量子产率为13.60%,XPS谱图表明碳量子点掺杂Si,且富含甲亚胺基团和硅氧键。Cu~(2+)对碳量子点荧光产生猝灭作用,依据Cu~(2+)浓度与碳量子点荧光强度猝灭率的相关性,建立碳量子点荧光探针测定水样中Cu~(2+)的分析方法,其它金属离子对Cu~(2+)干扰程度较小,回收率为91.4%~100.8%,检出限为0.13μmol/L,相对标准偏差为0.20%~0.92%。