Determination of rutin and quercetin in hypericum japonicum by capillary electrophoresis with

建立了毛细管电泳电化学分离检测田基黄中生物活性成分芦丁和槲皮素的方法。考察了检测电极电位、缓冲液浓度、pH、运行电压和进样时间对分离的影响。以40 cm长,50μm内径的石英毛细管作为分离通道,运行缓冲液为25 mmol/L硼砂(pH 9.2)溶液,分离电压12 kV,0.3 mm直径的铂圆盘电极为检测电极,检测电位1.00 V(vs.Ag/AgCl),芦丁和槲皮素在10 min内得到良好分离。在上述实验条件下,芦丁和槲皮素分别在8.2×10-6~5.2×10-4mol/L与6.8×10-6~7.2×10-4mol/L范围内与峰面积呈良好线性关系,检出限分别为9.0×10-7mol/L(S/N=3)和4.7×10-7mol/L(S/N=3)。方法已应用于田基黄药材提取物成分分析。Abstract: A method based on capillary electrophoresis with amperometric detection was established for the separation and determination of rutin and quercetin in hypericum japonicum． Detection potential， buffer concentration and pH，separation voltage and injection time were investigated to acquire the optimum condition． An uncoated silica capillary column ( 50 μm i． d． × 40 cm) was used as the separation channel，the two analytes could be well separated within 10 minutes by using 25 mmol /L sodium borate buffer( pH9． 2) and 12 kV as the separation voltage． The detection electrode was a platinum disk electrode ( 0． 3mm i． d． ) and the detection potential was 1． 00 V ( vs． Ag /AgCl) ． Under the optimized experimental conditions mentioned above，there was a good linear relationship for rutin ranging from 8． 2 × 10 － 6 mol /L to 5． 2 × 10 － 4 mol /L as well as 6． 8 × 10 － 6mol /L to 7． 2 × 10 － 4mol /L for quercetin． The detection limits for rutin and quercetin were 9． 0 × 10 － 7mol /L ( S /N = 3) and 4． 7 × 10 － 7mol /L ( S /N = 3) ，respectively． The method has been successfully used for the assay of bioactive compounds in hypericum japonicum extracts．广西壮族自治区自然科学基金项目(0640038)资

Seperation and determination of cimetidine by capillary electrophoresis with electrochemiluminescence

建立了以三联吡啶钌为发光体系的毛细管电泳电化学发光(CE-ECL)检测系统,并应用于分离和测定西咪替丁片剂中西咪替丁的含量。考察了检测电位,三联吡啶钌(Ru(bpy)32+)的溶液浓度,缓冲液的pH和溶液浓度,分离电压、进样电压与进样时间等因素对分离检测的影响。结果表明:在检测电位1.18V,Ru(bpy)32+溶液浓度为5 mmol/L,磷酸盐缓冲液(PBS)25 mmol/L(pH 7.8),进样时间10 s,进样电位10 kV,运行电位15 kV下,测得西咪替丁线性范围为2.8×10-6~4.0×10-4mol/L,检出限为1.2×10-7mol/L(S/N=3)。对1.0×10-5mol/L的西咪替丁标准溶液连续测定5次,电化学发光强度和迁移时间的RSD分别为3.9%和1.5%。方法已应用于西咪替丁片剂中西咪替丁含量的测定。Abstract: A sensitive and simple method based on capillary electrophoresis( CE) with electrochemiluminescence ( ECL) detection has been developed for the separation and determination of cimetidine in cimetidine tablets． The effects of detection potential，the concentration of tris ( 2，2 '-bipyridyl) ruthenium( Ⅱ) ，the acidity and the concentration of the running buffer，separation voltage，injection voltage，injection time and so on were investigated to acquire the optimum conditions． The detection electrode was a platinum microelectrode with a diameter of 90 μm at a detection potential of 1. 18 V ( versus Ag /AgCl) ． Cimetidine could be well separated within 6 min in a 50 cm length fused-silica capillary at a separation voltage of 15 kV in a 25 mmol /L PBS buffer ( pH 7. 8) ． The injection voltage and injection time are 10V and 10s． The response was linear over about three orders of magnitude ranging from 2. 8 μmol /L to 400 μmol /L for cimetidine． The detection limit ( S /N = 3) is 1. 2 × 10 － 7mol /L． Ｒelative standard deviations ( ＲSD) of no more than 4. 0% were obtained for both migration time and electrophoretic peak area． The proposed method was successfully applied to the analysis of active ingredients in cimetidine tablets with satisfactory assay results．广西壮族自治区自然科学基金(0640038)资

毛细管电泳法快速测定预知子中α-常春藤皂苷含量

预知子为木通科植物木通、三叶木通或白木通的干燥近成熟果实,收载于《中国药典》2010年版一部[1]。其味苦、性寒,具有疏肝理气、活血止痛、散结、利尿之功效,主治脘胁胀痛、痛经闭经、痰核痞块、小便不利。药理研究表明,预知子具有抗肿瘤、利尿、抗菌、消炎和降压等作用[2-4]。文献[5-7]报道,预知子中的主要成分是皂苷类化合物,具有保肝、抗肿瘤[8]、抗菌和消炎等生物活性。其中α-常春广西壮族自治区自然科学基金(0640038

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors