血红蛋白存在下胆碱酯酶活性的5,5′-二硫双-2-硝基苯甲酸分光光度测定法

5 ,5′二硫双 - 2 -硝基苯甲酸 (DTNB)分光光度测定法是检测乙酰胆碱酯酶酶活性的最灵敏的方法。但血液样品如兔网织红细胞裂解物样品中血红蛋白的存在会极大地干扰呈色反应 ,因此我们采用蛋白质变性剂三氯乙酸沉淀血红蛋白 ,再用NaOH将上清液校回中性的方法 ,对原DTNB法进行改良。改进后的DTNB法较原DTNB法大大降低了背景干扰 ,提高了检测灵敏度。     

新试剂4，4′-2（2-氯-4-硝基重氮氨基）联苯分光光度法测定水中阳离子表面活性剂

目的：建立了分光光度法测定氯化十四烷基二甲基苄铵的新方法。方法：在pH11．5—12．5碱性介质中，利用4，4′-二（2-氯-4-硝基重氮氨基）联苯（CNDADP）与氯化十四烷基二甲基苄铵（Zeph）的显色反应，在最大吸收波长580nm处，用光度法测定水样中微量的Zeph。结果：Zeph的浓度在0～3．0×10%^-5mol／L范围内符合比耳定律。表观摩尔吸光系数为2．39×10^4/mol·cm。结论：方法简单，灵敏度高，选择性较好，可用于水中微量氯化十四烷基二甲基苄铵的测定。     

新试剂4,4′-二(2-氯-4-硝基重氮氨基)联苯分光光度法测定水中阳离子表面活性剂

目的:建立了分光光度法测定氯化十四烷基二甲基苄铵的新方法。方法:在pH 11.5~12.5碱性介质中,利用4,4′-二(2-氯-4-硝基重氮氨基)联苯(CNDADP)与氯化十四烷基二甲基苄铵(Zeph)的显色反应,在最大吸收波长580 nm处,用光度法测定水样中微量的Zeph。结果:Zeph的浓度在0~3.0×10-5mol/L范围内符合比耳定律。表观摩尔吸光系数为2.39×104L/mol.cm。结论:方法简单,灵敏度高,选择性较好,可用于水中微量氯化十四烷基二甲基苄铵的测定。     

全自动化分析仪测定血清铁

以2-（5-溴-2-吡啶偶氮）-5-[（N,N-二羧基甲基）氨基]苯酚（5-Br-PADCAP)作显色剂,在pH6.5 HAc-NaAc缓冲液中测定血清铁。     

间苯三酚分光光度法测定植物饮料中的戊聚糖

目的:建立间苯三酚分光光度法测定植物饮料中戊聚糖的分析方法。方法:样品中戊聚糖经热盐酸水解产生戊糖,用间苯三酚测定水解液中戊糖间接分析戊聚糖含量。结果:方法线性范围为40 mg/L～400 mg/L,线性方程为y=0.0017x+0.0043,r=0.9991,方法的检出限为4 mg/L,对含量为1.45%的液体戊聚糖饮料进行6次平行测定,RSD为2.03%。对含量为16.8%的固体戊聚糖粉进行6次平行测定,RSD为2.33%。结论:该法快速、准确、检测限低、精密度高,适用于植物饮料中的戊聚糖的检测。     

Flow-injection spectrophotometric method with on-line photodegradation for determination of ascorbic acid and total sugars in fruit juices

This article reports a flow-injection spectrophotometric determination (FIA) with a photodegradation step to determine ascorbic acid and total sugars. The flow-injection system includes a simple ultraviolet photoreactor for the on-line photodegradation. The method is based on the determination of ascorbic acid at 300 nm before the photodegradation step, followed by UV irradiation and measurement of total sugars at 268 nm. The proposed method was used to determine ascorbic acid and total sugars in commercial and natural fruit juice samples. The method was validated by using spiked samples with recoveries in the range 96.4-108.3% for ascorbic acid, and 91.0-113.2% for total sugars.     

火焰原子吸收分光光度法测定尿锰的方法研究

目的:探索尿锰检测的新方法。方法:采用原子吸收火焰法直接测定,同时在样品消化时采用了浓氨水沉淀,又用250 m l凯氏氮瓶消化法。结果:回收率:90.0%~99.5%;相对标准偏差为2.4%;方法检出限为0.0190 mg/L。结论:该法样品消化简单,回收率高,适宜大批量样品检测。     

A novel spectrophotometric method for the determination of aminophylline with boric acid in pharmaceutical and mixed serum samples

This paper firstly describes a novel method to determine aminophylline (Ami) with boric acid (BA) by spectrophotometry. The study indicates that at pH 12.00 the absorbance of Ami decreases when BA is added. A simple, rapid, sensitive and reliable novel method based on the product of Ami and BA is obtained. Beer's law is obeyed in the range of Ami concentrations of 0.20-200 microg ml(-1). The equation of linear regression is A=-2.57309x10(-4)-0.00355C (microg ml(-1)), with a linear correlation coefficient of 0.9969 and RSD 0.28%. The method is successfully applied to the determination of Ami in pharmaceutical samples and mixed serum samples, and average recoveries were in the range of 97.1-105.9%.     

全血中硒的氢化物发生原子吸收分光光度测定法

取全血样品0.1～0.8ml,加2ml混合消化液,在管式电热消化器上加热消化。消化后的样品在酸性溶液中加KI还原后定容,在氢化物发生器内用硼氢化钠还原成硒化氢,导入石英原子化器中,进行原子吸收测定。本方法的检测限为10μg/L;同一血样6次测定±s为(100±5.1)μg/L,RSD为5.1%;用本方法测定了冻干牛血硒标准物质和牛血清标准物质,测定结果均落在标准物质的不确定度范围内。     

A spectrophotometric method for the determination of organic soluble matter in bitumen fumes

A UV spectrophotometric procedure was validated for the determination of organic soluble matter in bitumen fumes collected by filtration technique. Ultrasonic extraction was carried out with toluene, an efficient extraction solvent for polycyclic aromatic hydrocarbons, followed by UV absorbance measurements at 320 nm. A calibration curve is plotted from the same set of samples determined by classical weighing method. Further determinations can also be made using the slope factor of the calibration curve. The procedure presents obvious simplicity and rapidity advantages and is less prone to losses than the measurements of weight. Inter-method comparisons of samples collected from experimental laboratory-generated penetration bitumen fumes commonly used in road paving showed that the three available procedures-weighing, infrared, and UV--described for the determination of organic soluble matter yield equivalent results.     

New spectrophotometric method for the quantitative determination of melamine using Mannich reaction

The objective of this study was to develop a spectrophotometric method for the quantitative determination of melamine. The method was based on the complexation of melamine with a mixture of formaldehyde and chemicals including a ketone group, as described by the Mannich reaction. The complex was determined by spectrophotometric absorption measurement as it is characterized by specific spectroscopic properties that are related to the chromophore of the ketone compounds. Uranine was tested as a ketone compound. The UV spectrum of the complex presented a maximum of absorption at 214 nm. An internal standard was added to quantify the melamine. The method was tested to determine the level of melamine in food, using a contaminated fish sample from China. The recovery value was 97% and the limit of detection was 0.063 μg/mL.