土茯苓中总黄酮的含量测定方法研究

目的：建立土茯苓总黄酮的含量测定方法。方法：采用70%乙醇超声提取工艺和可见分光光度法测定土茯苓中总黄酮的含量,以芦丁为对照品,在500 nm波长处测量。结果：芦丁在0.008～0.048 mg.mL-1范围内线性关系良好（r=1.000）,平均加样回收率（n=6）以芦丁计为98.34%,RSD为3.4%。结论：此方法操作简单,精密度、稳定性和重复性良好,可用于土茯苓总黄酮含量测定。     

土茯苓中总黄酮的含量测定方法研究

目的:建立土茯苓总黄酮的含量测定方法。方法:采用70%乙醇超声提取工艺和可见分光光度法测定土茯苓中总黄酮的含量,以芦丁为对照品,在500 nm波长处测量。结果:芦丁在0.008～0.048 mg.mL-1范围内线性关系良好(r=1.000),平均加样回收率(n=6)以芦丁计为98.34%,RSD为3.4%。结论:此方法操作简单,精密度、稳定性和重复性良好,可用于土茯苓总黄酮含量测定。     

经典名方温胆汤物质基准总黄酮、柚皮苷和新橙皮苷含量测定

目的：研究并建立紫外分光光度法（UV）和高效液相色谱法（HPLC）分别测定温胆汤物质基准中总黄酮、柚皮苷和新橙皮苷含量。方法：以柚皮苷为对照品，采用紫外-可见分光光度法测定总黄酮的含量并采用HPLC法测定柚皮苷和新橙皮苷的含量。结果：采用直接测定法测定总黄酮类成分在284 nm处有较强吸收，柚皮苷在20.22～80.88μg/mL范围内与吸光度呈良好的线性关系，平均加样回收率为98.33%。柚皮苷和新橙皮苷分别在0.01～0.51 mg/mL和0.01～0.50 mg/mL范围内有良好的线性关系，精密度、稳定性、重复性的RSD均小于5.0%，加样回收率分别为97.11%和102.72%；温胆汤物质基准中总黄酮的平均含量为15.03%，柚皮苷、新橙皮苷的平均含量分别为22.78 mg/g和9.75 mg/g。结论：建立的温胆汤物质基准总黄酮、柚皮苷和新橙皮苷含量测定方法简单、稳定、重复性好，为温胆汤及其相关制剂进一步研究和开发提供实验基础。     

RP-HPLC法测定酸枣仁汤中芒果苷的含量

目的：建立测定酸枣仁汤中芒果苷含量的反高效液相色谱分析方法。方法：色谱柱：WatersC18（250nm×4.6mm,5μm）;流动相：乙腈-0.1%磷酸水溶液,梯度洗脱;流速：1.0ml/min,检测波长：257nm。结果：芒果苷在0.316μg-1.264μg范围内与峰面积线性关系良好（r=0.9999）,平均加样回收率为97.64%,RSD为0.36%。结论：本方法简便、准确、可靠、重复性好,可作为酸枣仁汤中芒果苷的含量测定方法。     

荧光法测定果蔬中叶酸含量的研究

目的：建立水果蔬菜中叶酸含量的荧光测定方法。方法：样品经NaOH提取后,在0.2mol/L HAc-NaAc（pH=4.76）反应介质中被KMnO4氧化,空白以1mol/L H2SO4作为反应介质进行氧化,在λex=280nm、λem=445nm条件下测定。结果：叶酸浓度在6.0～90μg/L范围内与ΔIF呈线性关系,线性回归方程为ΔIF=778.24C+1.1,r=0.9998;方法精密度为1.49%;对猕猴桃、苹果、梨、菠菜中叶酸含量进行测定,精密度为2.65%～9.95%,加标回收率为86.0%～107.5%,相对标准偏差为2.52%～8.73%。结论：本方法提取过程简单、灵敏度高、结果的精密度和准确度高,可用于水果蔬菜中叶酸的测定。     

深色果蔬维生素C检测方法的优化与比较

目的：优化2,6-二氯靛酚钠滴定法和高效液相色谱法检测维生素C含量操作规范性及适用性。方法：对检测条件的设置、试剂及样液的保存时间、提取剂及浓度的选择、提取过程、脱色剂用量及2种检测方法的精密度、重复性和加标回收率等关键影响因素进行比较。结果：高效液相色谱法检测设置C18（5μm,4.6×250mm）色谱柱,0.1%草酸为流动相,流速1mL/min,柱温30℃,检测波长254nm,所得图谱保留时间适宜,峰形良好,维生素C标准液浓度在0.025～0.3mg/mL范围内线性关系良好,回归方程为：y=46 116x+173.26,R2为0.999 2;维生素C标准液在4～6℃保存下48h内可用、2,6-二氯靛酚钠溶液在4～6℃保存下应在12d内使用,待测液制备完成后应立即测定,若无法立即测定,可于4～6℃冰箱中保存1.5h;2%草酸为提取剂效果最佳,样品加提取液匀浆后迅速定容、过滤和检测,不可久置;使用2,6-二氯靛酚钠滴定法时需添加0.4g/30mL的活性炭进行脱色;精密度、重复性及加标回收率均符合测定要求。结论：2种检测方法都适用于深色果蔬维生素C含量检测,各有特点,可根据测定要求及实际条件选择适宜的方法。     

水龙骨中总黄酮的含量分析

目的:对水龙骨中总黄酮含量进行测定,为水龙骨质量评价提供依据.方法:芦丁-UV方法进行测定.结果:总黄酮在0.001 68～0.067 2 mg/mL范围有良好的线性关系(r=0.999 1),加样回收率为98.23%,RSD=3.52%.结论:该法样品处理简单、迅速,可以做为水龙骨中总黄酮的含量测定方法.     

茉莉花渣多糖含量测定方法的建立及抗氧化作用研究

建立了茉莉花渣多糖含量的测定方法,并对茉莉花渣多糖进行了抗氧化作用研究,结果表明:采用蒽酮-硫酸比色法以624 nm为测定波长在质量浓度为10~60 mg.L-1(R2=0.9993)范围内与吸光度呈良好线性关系,该法的平均加样回收率为100.17%,重复性良好(RSD=0.57%),测定准确可靠。茉莉花渣多糖在0.2~1.0 g.L-1范围内对.OH具有明显的清除作用,IC50为0.52 g.L-1。     

复方黄柏液的质量标准研究

本研究旨在建立复方黄柏液质量标准控制方法。实验采用薄层色谱法与高效液相色谱法对复方黄柏液中的盐酸小糪碱、绿原酸进行定性鉴别及含量测定。结果表明,复方黄柏液的盐酸小糪碱、绿原酸的薄层色谱中,在与对照品色谱相应的位置上,显相同颜色的斑点,阴性无干扰;HPLC 法测定盐酸小糪碱进样量在0.09～ 0.45 μg（r = 0.9998）范围内线性关系良好,平均加样回收率为103.4%;绿原酸进样量在0.9～4.5 μg（r = 0.9999）范围内峰面积线性关系良好,平均加样回收率为100.2%。检测出复方黄柏液中盐酸小糪碱含量平均为0.0222 mg/ml,绿原酸含量平均为0.382 mg/ml。研究证明,该方法可用于复方黄柏液的质量控制。     

RP-HPLC 法测定酸枣仁汤中甘草苷的含量

目的:建立测定酸枣仁汤中甘草苷含量的反相高效液相色谱分析方法。方法:色谱柱:WatersC18(250nm×4.6mm,5μm);流动相:乙腈-0.1%磷酸水溶液,梯度洗脱;流速:1.0ml/min,检测波长:276nm。结果:芒果苷在0.093μg-0.744μg范围内与峰面积线性关系良好(r=0.9999),平均加样回收率为98.04%,RSD为0.41%。结论:本方法简便、准确、可靠、重复性好,可作为酸枣仁汤中甘草苷的含量测定方法。     

一种测定蛹虫草中虫草酸含量的酶标仪微量反应方法

研究和建立一种基于酶标仪-96孔板高通量测定虫草酸含量的检测方法,并对该方法进行性能评价。以酶标仪为检测仪器,在96孔板内按照设定反应条件微量加入样品和试剂进行显色反应,利用酶标仪测定吸光度值并计算虫草酸含量。通过检测精密度、重复性、回收率,并与分光光度计法进行比较,综合评价该方法的准确度、精确度。结果表明,测定数据具有较高的精密度（样品CM1的RSD值0.829%;样品CM2的RSD值1.772%)、重复性（标准样品B40的RSD值2.061%;样品CM2 的RSD值1.599%)、回收率（平均回收率99.24%,RSD值3.666%）,测定结果与分光光度法检测结果无显著差异(P>0.05)。结果表明,酶标仪微量法测定准确、重复性好,并可大大减少样品和试剂的用量,该方法方便、快捷、高效,可以替代分光光度法用于虫草酸含量的测定。     

Wide concentration range investigation of recovery, precision and error structure in liquid chromatography

Using a typical HPLC assay, the characteristics of recovery, system precision and repeatability were investigated over a wide concentration range. In the presence of a constant amount of typical tablet excipients, the antidiabetic drug glibenclamide was analyzed in the range from 0.24 to 0.005mg/mL (18 concentration levels, 6 independent sample preparations each). On the basis of a typical concentration for an HPLC glibenclamide assay of 0.2mg/mL, this corresponds to a relative amount of 120-0.025% label claim. In the range from 120 to 0.075%, the recovery was found to be quite constant and systematically heightened mainly due to the evaporation from vials during centrifuging and the displacement of solvent volume by the added matrix. Both system precision and repeatability remain almost constant in the interval from 120 to 10% at a R.S.D.% of 0.31 and 0.70%, respectively, indicating that the sample preparation is the major error source in this range (0.63%). Between 10 and 0.25%, a linear relationship between the logarithmized concentration and the repeatability was noted. However, for lower amounts close to the limit of quantitation, the R.S.D.% of measurements increases much more distinctly. This increase is caused by a strong rise of the system precision. At this concentration range, system precision and repeatability are not significantly different any longer. This leads to the conclusion that with the injection error being constant the peak integration error becomes the dominating error source at low concentrations, e.g. at concentrations below the five-fold of the LOQ. The results obtained here agree well with earlier published data. As the quantitation limit of 0.05% can be regarded as typical for a pharmaceutical impurity control test, generalizations of these findings from this extensive data set should be possible. In this context, peak integration and improvements of the signal-to-noise ratio are the most promising measures to improve an unsatisfactory precision in LC.     

Residue analysis of organophosphorus and organochlorine pesticides in fatty matrices by gas chromatography coupled with electron-capture detection

A multiresidue method for the simultaneous determination of 22 organochlorine (OCs) and organophosphorus (Ops) pesticides (including isomers and metabolites), representing a wide range of physicochemical properties, was developed in fatty matrices extracted from meat. Pesticides were extracted from samples with acetonitrile/n-hexane (v:v, 1:1). The analytical screening was performed by gas chromatography coupled with electron-capture detection (ECD). The identification of compounds was based on their retention time and on comparison of the primary and secondary ions. The optimized method was validated by determining accuracy (recovery percentages), precision (repeatability and reproducibility), and sensitivity (detection and quantitation limits) from analyses of samples fortified at 38 to 300 ng/g levels. Correlation coefficients for the 22 extracted pesticide standard curves (linear regression analysis, n = 3) ranged from 0.998 to 1.000. Recovery studies from 2 g samples fortified at 3 levels demonstrated that the GC-ECD method provides 64.4-96.0% recovery for all pesticides except 2,4'-DDE (44.6-50.4%), 4,4'-DDE (51.1-57.5%) and 2,4'-DDT (50.0-51.2%). Both repeatability and reproducibility relative standard deviation values were < 20% for all residues. Detection limits ranged from 0.31 to 1.27 ng/g and quantification limits were between 1.04 and 4.25 ng/g. The proposed analytical method may be used as a simple procedure in routine determinations of OCs and Ops in meat. It can also be applied to the determination of pesticide multi-residues in other animal products such as butter and milk.     

Extraction of urinary pregnanediol and estriol by the Bio-Rad column

In the present study, we have evaluated the quality control parameters of a new method for the determination of the urinary Pregnandiol and Estriol using a small column AG 1X2 proposed by Bio-Rad Laboratories. The principle of this method is based on a single extraction of steroids by ion exchange and methanol elution under different pH conditions. Compared to the "classical" methods using solvent extraction, the present method has some advantages mainly the elimination of the use of large volumes of solvents and the reduction of the sample volume to be analyzed. The preliminary results showed a recovery of 89,0% - 98,9% (C.V. = 5%) for Estriol and 83,8% - 93, 2% C.V = 5%) for Pregnandiol . The precision of the method evaluated by its repeatability and between-assay reproductibility showed 4% and 6% variation for Estriol and Pregnandiol . The Comparison of the present method with a classical one using Ether/Ethanol (4/1) for extraction gave us a very good correlation.     

Sensitive high-performance thin-layer chromatographic method for the estimation of diospyrin, a tumour inhibitory agent from the stem bark of Diospyros montana Roxb.

Diospyrin, a tumour inhibitory agent from the stem bark of Diospyros montana was isolated and characterised. A sensitive high-performance thin-layer chromatographic (HPTLC) method was developed for the estimation of diospyrin. The method was validated for precision (intra- and inter-day), repeatability and accuracy. The method was found to be precise, with the RSDs for intra-day in the range of 0.72–1.85% and RSDs for inter-day in the range of 1.06–2.95%, for different concentrations. Instrumental precision and repeatability of the method were found to be 0.086 and 0.937 (% CV), respectively. Accuracy of the method was checked by performing the recovery study at two levels and average percentage recovery was found to be 97.87%. The developed HPTLC method was adopted for the estimation of diospyrin content of the stem bark of D. montana from different regions, which varied from 0.35 to 0.47% (w/w) in the samples.     

Assay of coenzyme Q(10) in plasma by a single dilution step

A new method is described for determining coenzyme Q(10) (CoQ(10)) in plasma. The method is based on oxidation of CoQ(10) in the sample by treating it with para-benzoquinone followed by extraction with 1-propanol and direct injection into the HPLC apparatus. This method achieves a linear detector response for peak area measurements over the concentration range of 0.05-3.47 microM. Diode array analysis of the peak was consistent with CoQ(10) spectrum. Supplementation of the samples with known amounts of CoQ(10) yielded a quantitative recovery of 96-98.5%; the method showed a level of quantitation of 1.23 nmol per HPLC injection (200 microl of propanol extract containing 33.3 microl of plasma). A correlation of r = 0.99 (P < 0.0001) was found with a reference electrochemical detection method. Within run precision showed a CV% of 1.6 for samples approaching normal values (1.02 microM). Day-to-day precision was also close to 2%.     

Quantification of melittin and apamin in bee venom lyophilized powder from Apis mellifera by liquid chromatography-diode array detector-tandem mass spectrometry

A high-performance liquid chromatography-diode array detector-tandem mass spectrometry (HPLC-DAD-MS/MS) method was developed for simultaneous determination of melittin and apamin in crude bee venom lyophilized powder (CBVLP) as the traditional Chinese medicine possessing specific biological activity. Melittin and apamin were extracted with pure water from CBVLP samples followed by HPLC-DAD-MS/MS analysis. The method was validated to demonstrate its selectivity, linearity, limit of quantification (LOQ), intraday precision, interday precision, accuracy, recovery, matrix effect, and stability. The assay was linear over the concentration ranges of 1-100 and 0.2-25 μg/ml with limit of quantifications (LOQs) of 1.0 and 0.3 μg/ml for melittin and apamin, respectively. The precision results were expressed as coefficients of variation (CVs), ranging from 2.2% to 11.4% for intraday repeatability and from 3.2% to 13.1% for interday intermediary precision. The concentrations of endogenous melittin and apamin in CBVLP samples ranged from 46% to 53% and from 2.2% to 3.7% of dry weight, respectively. This rapid, simple, precise, and sensitive method allowed the simultaneous determination of melittin and apamin to evaluate authenticity and quality of CBVLP samples.     

Chromatographic analysis of Kutajarista--an ayurvedic polyherbal formulation

Kutajarista is a well known polyherbal preparation of which the main ingredient is the stem bark of Holarrhena antidysenterica. This Ayurvedic medicine is prescribed to treat amoebic dysentery and other disorders such as fever, indigestion and malabsorption syndrome. Herbal medicines are very important since, in common with conventional medicines, they contain biologically active substances that may produce non-trivial side effects when taken in excessive amounts. Very low doses, on the other hand, may have no therapeutic value. In this paper we report the chemical standardisation of Kutajarista by HPLC analysis based upon the presence of the biomarker conessine in the formulation. The standardisation method is simple and reliable, and the precision of method has been tested for repeatability (n = 3) and reproducibility (n = 9). The response of a refractive index detector was linear in the concentration range of 0.1-1.0 mg/mL. Recovery studies were performed to check the method for accuracy. The recovery was found to be in range of 99-105%. The developed HPLC method can be used to quantify conessine for quality control of marketed Kutajarista samples.     

基于比浊法的杆菌肽定量测定方法优化

杆菌肽在研究应用过程中,定量测定方法不统一,结果缺乏参考性。为规范其测定方法,拟通过建立杆菌肽浓度对数值与OD600之间的线性关系,以重复性和精密度为指标,优化指示菌初始浓度、杆菌肽溶液与菌悬液的比例、培养时间等因素,确定比浊法测定杆菌肽抑菌活性的方法。结果显示,比浊法的最适测定条件为:指示菌初始浓度107 CFU/mL,杆菌肽溶液与菌悬液比例1∶9,培养时间4 h,在此条件下,线性关系良好,R2达到0.99以上,且具有良好的重复性。进一步选用大肠杆菌和金黄色葡萄球菌验证方法的可行性,方法重复性好,精密度高。研究结果将为比浊法的进一步应用以及杆菌肽在试验和生产过程中的定量测定提供参考和依据。     

The use of a monolithic column to improve the simultaneous determination of four cephalosporin antibiotics in pharmaceuticals and body fluids by HPLC after solid phase extraction--a comparison with a conventional reversed-phase silica-based column

The use of a monolithic column (Chromolith, SpeedROD RP-18e, by Merck) was studied on the determination of cephalosporin antibiotics. Results were compared with those from a previously developed analytical method using conventional silica-based analytical column. A rapid, accurate and sensitive method has been developed and validated for the quantitative simultaneous determination of four cephalosporins: Cephalexine and Cephadroxil (first generation), Cefaclor (second generation) and Cefotaxim (third generation) in pharmaceuticals as well as in human blood serum and urine. Hydroflumethiazide (HFM) (3,4-dihydro-6(trifluoromethyl)-2H-1,2,4-benzothiadiazine-7-sulfonamide-1,1-dioxide) was used as an internal standard at a concentration of 1.5 ng/microL. A rectilinear relationship was observed up to 5 ng/microL for the four compounds. Analysis time was less than 4 min. The statistical evaluation of the method was examined by means of within-day repeatability (n=8) and day-to-day precision (n=8) and was found to be satisfactory with high accuracy and precision results. The method was applied to the determination of the cephalosporins in commercial pharmaceuticals and in biological fluids: human blood serum after solid phase extraction and urine simply after filtration and dilution. Recovery of analytes in spiked serum samples was in the range from 88.7 to 107.8%, while for urine samples recovery was from 98.0 to 105.6%. By comparing the figures of merit for the monolithic column and the silica-based one, regarding the determination of the four cephalosporins investigated in the present study, the outstanding efficiency of the monolithic column can be noticed.