顺序注射化学发光法测定药物中的抗坏血酸

基于在酸性介质中KMnO4氧化抗坏血酸产生化学发光反应,HCHO的存在能使发光强度增强的原理,建立了顺序注射技术与化学发光分析联用测定痕量抗坏血酸的新方法。对进样顺序、体积、流速和浓度各因素进行了优化,在150μL进样体积下,方法的线性范围为1.0×10-9~2.0×10-6mol/L,检出限(3σ)为5.0×10-10mol/L,方法的相对标准偏差为1.3%(1.0×10-7mol/L,n=11)。采样频率为80样/h。应用该法测定维生素C针剂和片剂中的抗坏血酸,结果与标准方法一致。     

顺序注射停流分光光度法测定痕量碘

食物中碘的含量一直是人们关注的问题,研究食物中微量碘的分析方法具有重要的现实意义.目前测定碘的方法主要有色谱法[1,2]、荧光法[3,4]、分光光度法[5,6]等.     

微顺序注射-分光光度法快速测定海水中总磷

基于微顺序注射-阀上实验室,采用磷钼蓝分光光度法测定了海水中总磷,对实验参数进行了优化,并选取了海水中主要成分离子进行了干扰实验。结果表明,海水中总磷质量浓度在0.009~1mg/L范围内与吸光度呈线性关系(r=0.9995),方法的检出限为0.003mg/L。该法测定秦皇岛黄金海岸表层海水中总磷浓度为0.090mg/L,与国标法测定结果0.088mg/L无显著性差异;测定含磷浓度为0.20mg/L的人工海水,相对标准偏差(RSD)为2.4%,样品加标回收率为94.4%~95.7%;海水中主要离子对本实验方法测定产生的干扰在5%以内。     

测定水中痕量Cr(Ⅵ)的电渗泵顺序注射分光光度法

采用电渗泵顺序注射－分光光度法对水中痕量Cr(Ⅵ）进行了测定，方法通过改变电渗泵流量，流动方向及阀注入时间，实现试剂和样品的定量注入和反应时间的控制；泵工作电压为直流200V，流量为0．45mL/min显色剂采用二苯碳酰二肼，显色剂进样时间为30s，样品进样时间为15s，反应生成的紫红色配合物在540nm处检测，该法线性范围为0．010－1．20mg/L Cr(VI)，检出限为3．4μg/L，应用该法成功地进行了地表水中Cr(Ⅵ）的测定。     

顺序注射停留分光光度法测定磺胺乙酰钠

在HCl浓度为5.0×10-4mol/L时,磺胺乙酰钠-NaNO2-1-萘胺的重氮化偶合反应,生成不稳定的红色产物,利用顺序注射停留技术在473nm波长处检测该不稳定产物,建立了快速自动测定磺胺乙酰钠的新方法。该方法线性范围为5～2500μg/mL,检出限为0.018μg/mL,进样频率为62个/h。应用于药物中磺胺乙酰钠的测定,并与药典规定方法进行对照。     

气体扩散耦合顺序注射分光光度法测定葡萄酒中的二氧化硫

依据在微碱性条件下,亚硫酸根离子可与孔雀绿溶液发生加成反应并使其褪色的原理,建立了气体扩散耦合顺序注射分光光度法测定葡萄酒中二氧化硫的新方法。当接收液流速为1.2mL/min和4.2mL/min时,方法的线性响应范围分别为1.0~5.0μg/mL和5.0~50.0μg/mL,方法的检出限为0.33μg/mL,相对标准偏差(RSD)≤0.43%,对葡萄酒样中二氧化硫测定的加标回收率为98.7%~104.7%。     

铁(Ⅲ)-邻菲啰啉体系流动注射-分光光度法测定药品中的抗坏血酸

本文基于抗坏血酸还原铁(Ⅲ)-邻菲啰啉为红色铁(Ⅱ)-邻菲啰啉,建立了流动注射分光光度法测定药品中抗坏血酸的方法。本法体系简单,操作方便、快速,标准加入试验的回收率为92～103％。     

顺序注射催化动力学光度法测定织物和室内空气中痕量甲醛

在磷酸介质中 ,甲醛可以催化溴酸钾氧化　花青的反应使其退色 ,据此建立了顺序注射催化动力学光度法测定织物和室内空气中痕量甲醛的新方法。方法的线性范围 0 .5～ 7.0 μg mL ,检出限 0 .1 μg mL。用于树脂整理特殊织物和室内空气中痕量甲醛的测定 ,回收率在 97.0 %～ 1 0 5 .0 %之间。     

吗啡的流动注射分光光度法分析研究

本文建立了吗啡的流动注射分光光度分析法。在优化条件下,线性检测范围为30～700μg/ml,回归方程为h=0.0250+1.74×10~(-3)C,相关系数为0.9999,并用于吗啡样品的分析。回收率为99.9％,相对标准偏差为0.43％,样品分析速度为240次/小时。     

抗坏血酸及L-半胱氨酸的流动注射动力学同时测定法

pH2～9时,抗坏血酸与L-半胱氨酸均可与Fe3+-邻菲咯啉混合液反应,生成Fe2+-邻菲咯咻有色配合物,但两者反应速度相差极大。根据这个原理,采用流动注射分析停流技术,建立了抗坏血酸与L-半胱氨酸的动力学吸光光度同时测定法。两者测定的线性范围分别为0～24mg·L-1和0～280mg·L-1,相应的检出限为1mg·L-1和16mg·L-1,抗坏血酸与L-半胱氨酸浓度分别为12.0mg·L-1和160.0mg·L-1时,测定的相对标准偏差分别为0.9％和0.6％,采样频率为30样·h-1。该法灵敏、快速、准确,选择性较高,且流路及设备简单,实用性强,用于实际样品测定,抗坏血酸及L-半胱氨酸的加标回收率分别可达95.2％和92.8％。     

11-Molybdobismuthophosphate—A new reagent for the determination of ascorbic acid in batch and sequential injection systems

The guanidinium salt of the new heteropolymolybdate 11-molybdobismuthophosphate Gua₆PBiMo₁₁O₄₀ (11-MBP) was synthesized, characterized and used as a reagent for batch spectrophotometric (SP) and sequential injection determination of ascorbic acid (AsA). When compared to other Keggin's heteropolyanions, the reduction of 11-MBP with AsA is both fast and maximal within a pH range of 1.6-2.0. The stoichiometry of the reaction was determined using molar ratio and continuous variation methods and was shown to be 1:1. The molar absorptivity of the reduced form of 11-MBP was 6.0 × 10³ L mol⁻¹ cm⁻¹ at 720 nm. The reaction is also specific for AsA. Only cysteine, hydroquinone and hydroxyacids were found to interfere with the reaction, while no interference was observed with the common reducing agents, including reducing sugars, catecholamines, nitrite, sulfite and iron(II) ions. Batch SP and sequential injection analysis (SIA) systems were developed for the determination of AsA, with calibration ranges of the SP methods at 2 × 10⁻⁶-8 × 10⁻⁵ M for a 10 mm cell and 5 × 10⁻⁷-3 × 10⁻⁵ M for a 50 mm cell and a limit of detection at 3 × 10⁻⁷ M. The linear range of the SIA method was 6 × 10⁻⁶-5 × 10⁻⁴ M, with a detection limit of 2 × 10⁻⁶ M and a sample throughput of 15 h⁻¹. The proposed methods were successfully used for the determination of AsA in both pharmaceuticals and fruit juices, and the results were consistent with those provided by the 2,6-dichlorophenolindophenol method.     

Sequential injection redox or acid-base titration for determination of ascorbic acid or acetic acid

Two sequential injection titration systems with spectrophotometric detection have been developed. The first system for determination of ascorbic acid was based on redox reaction between ascorbic acid and permanganate in an acidic medium and lead to a decrease in color intensity of permanganate, monitored at 525 nm. A linear dependence of peak area obtained with ascorbic acid concentration up to 1200 mg l⁻¹ was achieved. The relative standard deviation for 11 replicate determinations of 400 mg l⁻¹ ascorbic acid was 2.9%. The second system, for acetic acid determination, was based on acid–base titration of acetic acid with sodium hydroxide using phenolphthalein as an indicator. The decrease in color intensity of the indicator was proportional to the acid content. A linear calibration graph in the range of 2–8% w v⁻¹ of acetic acid with a relative standard deviation of 4.8% (5.0% w v⁻¹ acetic acid, n=11) was obtained. Sample throughputs of 60 h⁻¹ were achieved for both systems. The systems were successfully applied for the assays of ascorbic acid in vitamin C tablets and acetic acid content in vinegars, respectively.     

Non-equilibrium determination of metoclopramide and tetracaine hydrochloride by sequential injection spectrophotometry

A new sequential injection spectrophotometric method was proposed for the determination of metoclopramide and tetracaine hydrochloride. The method was based on the detection of an unstable red intermediate compound resulting from the reaction of metoclopramide or tetracaine hydrochloride with potassium dichromate, in the presence of sodium oxalate, in sulfuric acid solution. The related reaction mechanisms of this new method have been studied. The experimental conditions were optimized for the stopped-flow and continuous-flow sequential injection models. For continuous flow, the linear range for determination of metoclopramide, the detection limit and the sampling frequency were 13-130 μg ml⁻¹, 9.4 μg ml⁻¹ and 40 samples per hour, respectively. For stopped flow, they were 3-42 μg ml⁻¹, 1.0 μg ml⁻¹ and 18 h⁻¹, respectively. Adopting the continuous-flow model for tetracaine hydrochloride, the linear range was 25-300 μg ml⁻¹, and the detection limit was 18.0 μg ml⁻¹ with sampling frequency of 40 h⁻¹. This method has been used to determine metoclopramide and tetracaine hydrochloride in pharmaceutical preparations, and the results are compared with those determined by the pharmacopoeia method. Statistical analysis reveals that there was no evidence of significant difference between the methods.     

顺序注射分光光度法测定硫氰酸盐

根据硫氰酸盐、K2S2O8和3,5-二溴-吡啶偶氮-二乙基氨基苯酚反应形成紫红色产物的现象,建立了顺序注射分光光度测定硫氰酸盐的新方法,其线性范围为0．70～24．39μg/mL、检出限为0．25μg／mL。已用于工业废水和饮用水中硫氰酸盐的测定,回收率为96．0％-100．8％。     

Determination of paracetamol in pharmaceutical formulations using a sequential injection system

A simple method for the rapid determination of paracetamol in pharmaceutical formulations is described. The method involves oxidation of paracetamol by potassium hexacyanoferrate(III) and a subsequent reaction with phenol in the presence of ammonia. The blue complex formed is measured at 630 nm. The system has a sample frequency of 27 samples per h with a detection limit of 0.2 mg l⁻¹. The calibration curve is linear up to 60 mg l⁻¹ with a relative standard deviation of 1.2% (n=10).     

奋乃静的流动注射分光光度分析

基于在H2SO4介质中，K2S2O8氧化奋乃静生成红色中间产物的原理，建立了流动注射分光光度法测定药物中奋乃静含量的新方法。利用单纯形优化法选择了最佳实验条件。方法的线性范围为20-170μg/mL，检出限为0．46μg/mL，进样频率为150h。该方法用于奋乃静片剂中奋乃静含量的测定，其测定结果与药典法对照，无显著性差异。     

Flow-injection spectrophotometric determination of ascorbic acid by reduction of vanadotungstophosphoric acid

Ascorbic acid may be determined spectrophotometrically at 360 nm based on reduction of vanadotungstophosphoric acid using flow-injection analysis. The carrier stream was distilled water and the reagent streams were buffer solution (pH 3.0), 1.735 × 10^?3 M dodecatungstophosphoric acid and 1.735 × 10^?3 M sodium vanadate. The injection rate was 80 h^?1. The calibration graph was linear up to 80 μg ml^?1 ascorbic acid and the relative standard deviation for the determination of 20 μg ml^?1 ascorbic acid was 1.5% (n=10). The detection limit was 1.0 μg ml^?1 ascorbic acid, based on an injection volume of 250 μl. The system was applied to the determination of ascorbic acid in vitamin C tablets.     

Flow injection fluorometric determination of ascorbic acid using perylenebisimide-linked nitroxide

A simple and sensitive flow injection fluorometric method for the determination of ascorbic acid is described. Perylenebisimide-linked nitroxide (PBILN) is used as a fluorescent reagent, which permits the selective determination of ascorbic acid. The fluorescence of the perylenebisimide moiety in PBILN is quenched by the nitroxide moiety, which is linked to the perylenebisimide. When a stream of a solution of ascorbic acid is merged with a stream of PBILN, the ascorbic acid reacts with the nitroxide moiety of PBILN to form hydroxylamine, and the fluorescence properties of the perylenebisimide moiety are recovered. As a result, a peak-shaped fluorescence signal is produced, which can be observed by a fluorescence detector located downstream. Under optimized conditions, a good linear relationship between the concentration of ascorbic acid and peak height in the concentration range from 0.5 to 10 μmol L⁻¹ was found and the detection limit (S/N = 3) was 0.28 μmol L⁻¹. The relative standard deviation for the determination of 4.0 μmol L⁻¹ ascorbic acid samples was 1.0% (n = 5). The proposed method was applied to the determination of ascorbic acid in several soft drink beverages and the analytical results were in good agreement with those obtained using a conventional method.     

流动注射分光光度法测定亚硝酸根氮

使用北京吉天仪器有限公司水质分析仪样机建立了测定水中痕量亚硝酸根氮的流动注射光度方法,以先进的光纤光谱仪CCD作为检测器,亚硝酸盐与对氨基苯磺酰胺重氮化,再与盐酸N-（1-萘基）乙二胺偶合,形成玫瑰红色的偶氮染料,用分光光度法测定,其最大吸收峰在540nm处;最佳的显色管路长度1．5m;最佳的对氨基苯磺酰胺质量浓度为1.0g／L;最佳的N-（1-萘基）乙二胺质量浓度为60g／L,亚硝酸根氮的线性范围为0．002～1．0mg／L,检出限0．37μg／L,RSD0．2％,实际样品的加标回收率均在96.5％～101．2％之间,测定频率60样／h。