Kinetic spectrophotometric method for the determination of selenium(IV) by its catalytic effect on the reduction of spadns by sulphide in micellar media

A simple kinetic spectrophotometric method was developed for the determination of ultratrace amounts of Se(IV). The method is based on the reduction of spadns by sulphide in micellar media. The reaction was monitored spectrophotometrically by measuring the decrease in the absorbance of spadns at 515 nm with a fixed-time method. The decrease in the absorbance of spadns is proportional to the concentration of Se(IV) in the range 0.5–100 ng/mL with a fixed time of 2.5–7.0 min from the initiation of the reaction. The limit of detection is 0.3 ng/mL Se(IV). The relative standard deviation for the determination of 0.02 and 0.10 μg/mL Se(IV) was 2.10 and 1.95%, respectively. The method was applied to the determination of Se(IV) in water. The text was submitted by the authors in English.     

Simultaneous kinetic spectrophotometric determination of norfloxacin and rifampicin in pharmaceutical formulation and human urine samples by use of chemometrics approaches

A kinetic spectrophotometric method with aid of chemometrics is proposed for the simultaneous determination of norfloxacin and rifampicin in mixtures. The proposed method was applied for the simultaneous determination of these two compounds in pharmaceutical formulation and human urine samples,and the results obtained are similar to those obtained by high performance liquid chromatography.     

Determination of aniline in environmental water samples by alternating-current oscillopolarographic titration

A new method for the determination of aniline in environmental water based on oscillopolarographic titration was presented in this paper. Several factors including the kind, concentration, and volume of acid, the dosage of potassium bromide, the temperature and concentration of concomitant substances were investigated in detail. The experimental results indicated that this method was simple, rapid, and sensitive. The linear range was 8.367×10-4 to 2.789×10-2 mol L-1, the relative standard deviation (R.S.D.) was lower than 0.96%, and the spiked recoveries of aniline in environmental water samples were in the range of 99.4-106.9% under the optimal conditions. The results indicated that the present method could be used as an alternative method for aniline determination in realworld water samples.     

Trace determination of cobalt ion by using malic acid-malonic acid double substrate oscillating chemical system

A novel kinetic method for determination of trace amounts of cobalt ion was proposed and validated. The method is based on adding malic acid into classical Belousov-Zhabotinskii （B-Z） oscillating chemical system to form a double substrate one. The results showed that when the concentration of cobalt ion was in the range of 5.27× 10^-8 to 5.37 × 10^-12 mol L^-1, the change of the oscillating period was directly proportional to the negative logarithm of cobalt ion concentration. The sensitivity and precision of the developed method were quite satisfactory. The limit of detection was down to 5.20 × 10^-13 mol L^-1 which was a highest sensitivity found for determination of metal ions using oscillating chemical reaction so far. Some factors influencing the determination were also examined. The method has been successfully used to determine cobalt ion in vitamin B12 injection.     

Extractive Spectrophotometric Determination of Fluconazole by Ion-pair Complex Formation with Bromocresol Green

An extraction-spectrophotometric method for the determination of trace amounts of fluconazole was described. Fluconazole was effectively extracted as a 1 ： 1 ion-pair complex with bromocresole green （BCG） at pH 3.0 into chloroform, followed by spectrophotometric determination at 420 nm. Beer＇s law was obeyed over the range of 4-50 μg.mL^-1 of fluconazole with a detection limit of 3.7 μg.mL^-1 . The method is simple, rapid and sensitive. The procedure was applied to the determination of fluconazole in pharmaceutical preparations as well as its recovery from a blood serum sample.     

β-Cyclodextrin Enhanced Fluorimetric Method for Determination of Amoxicillin in Dosage

A simple sensitive spectrofluorimetric method was developed for the determination of amoxicillin. Amoxicillin in the presence of formaldehyde produces a fluorescent pyrazine derivative, whose fluorescence intensity can be enhanced by forming an inclusion complex with β-cyclodextrin. Optimum conditions for the determination of amoxicillin were also investigated. Fluorimetric detection was carried out at λex=365 nm and λem=445 nm. The linear range of this method for the determination of amoxicillin is 0.1―10 ...     

A RAPID FLUORIMETRIC DETERMINATION OF TYROSINE IN SERUM BY THE REACTION WITH CERIUM (Ⅳ)

A fluorimetric method for the determination of tyrosine in serum was proposed. The fluoriscence intensity is a linear function of tyrosine content in the range 0-1. 44ug/ml. The percentage of recovery was satisfactory.     

Osteryoung square wave voltammetric determination of lactose in food samples by a derivative procedure

A method for determination of lactose in food samples by Osteryoung square wave voltammetry （OSWV） was developed. It was based on the nucleophilic addition reaction between lactose and aqua ammonia. The carbonyl group of lactose can be changed into imido group, and this increases the electrochemical activity in reduction and the sensitivity. The optimal condition for the nucleophilic addition reaction was investigated and it was found that in NH4C1-NH3 buffer of pH 10.1, the linear range between the peak current and the concentration of lactose was 0.6-8.4 mg L-l, and the detection limits was 0.44 mg L- 1. The proposed method was applied to the ＇determination of lactose in food samples and satisfactory results were obtained.     

Spectrophotometric Study on the Interaction of Water with Chloranilic Acid and its Analytical Application

The reaction between chloranilic acid and water in alcohol was studied spectrophotometrically. The conditions of reaction were investigated in detail. The stable purple complex with an absorption wavelength at 530 nm was produced from the reaction between chloranilic acid and water. As a method for determination of H2O, Beer‘s law was obeyed in range of 0-6.0 % or 0-8.0 % (V/V) with the detection limit of 0.13 %. The relative standard deviation (RSD) was less than 2 %. The proposed method has been applied to determination of tracea mount of water in ethanol, flour and food flavoring, respectively. The recoveries of water in samples were 97～102%.     

阿莫西林与维多利亚蓝B的显色反应及应用

The color reaction of amoxicillin with victoria blue B was studied.A novel visible spectrophotometric method for the determination of amoxicillin has been established.Under pH 8.50～10.5 condition,victoria blue B reacteds with amoxicillin to form red ion association complex.The maximum absorption wavelength was at 630nm and the apparent molar absorptivity(ε) was 2.67×10~4 L·mol~(-1)·cm~(-1) and the linear ranges was 0～5.5 mg·L~(-1).Amoxicillin obey Beer's law in definite concentration range.The optimum reaction conditions and the methodological precision were studied simultaneity.The method was simple and rapid and sensitive for the determination of amoxicillin.This method has been applied to the determination of amoxicillin is in the city sell amoxicillin medicament is in point and average recovery at 98.2%～101.0%.     

Determination of silver ion based on the redshift of emission wavelength of quantum dots functionalized with rhodanine

A simple and selective method for the determination of silver ions was developed by utilizing the red- shift in emission wavelength of the core-shell CdSe/Cd5 quantum dots （QDs） functionalized with rhodanine upon the addition of Ag＋. A linear relationship was observed between the shift and the increase in concentration of Ag＋ in the range of 0.0125-12.5 μmol/L. The mechanism of the red-shift was investigated and suggested that the coordination between Ag＋ and rhodanine on the QDs surface caused an increase of particle size, which resulted in the red-shift of the QDs＇ emission wavelength. A detection limit of 2 nmol/L was achieved. The developed method showed superior selectivity and was successfully applied to the determination of silver in environmental samples.     

Determination of captopril in pharmaceutical preparation and biological fluids using two- and three-way chemometrics methods

Spectrophotometric method has been developed for the direct quantitative determination of captopril in pharmaceuticalpreparation and biological fluids(human plasma and urine)samples.The method was accomplished based on parallel factoranalysis(PARAFAC)and partial least squares(PLS).The study was carried out in the pH range from 2.0 to 12.8 and with aconcentration from 0.70 to 61.50 μg mL~(-1)of captopril.Multivariate calibration models such as PLS at various pH and PARAFACwere elaborated from ultraviolet spectra deconvolution and captopril determination.The best models for this system were obtainedwith PARAFAC and PLS at pH 2.0.The applications of the method for determination of real samples were evaluated by analysis ofcaptopril in pharmaceutical preparations and biological fluids with satisfactory results.The accuracy of the method,evaluatedthrough the RMSEP,was 0.5801 for captopril with best calibration curve by PARAFAC and 0.6168 for captopril with PLS at pH 2.0model.     

Determination of chlorine in titanium sponge by inductively coupled plasma optical emission spectroscopy with microwave digestionEI北大核心CSCD

A determination method for chlorinity in titanium sponge by inductively coupled plasma optical emission spectroscopyICP-OESwas established. The sample was fully dissolved by microwave digestion at high temperature. The spectral line of 134.724 nm was chosenand the effect of coexisting impurities of SiFe MnMgCaNiCr and main matrix was investigated. The results showed that there was no obvious interference for the determination of chlorine. A good linear relationship of chlorinity was exhibited in the range of 0-10 mg/Lr≥0.999with the standard addition recoveries of 98.7%-104% and the RSDs of 2.8%. This method could detect trace chlorine in titanium sponge reliabely. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

Study on the Supramolecular Interaction of β-Cyclodextrin with Gemfibrozil by Spectrofluorimetry and Its Analytical Application

The supramolecular interaction of gemfibrozil with β-cyclodextrin （β-CD） was studied by spectrofluorimetry. The mechanism of the inclusion was discussed by spectrofluoremetry, infrared spectrum and ^1H NMR spectrum. The results showed that a 1 ： 1 （β-CD ： gemfibrozil） complex was formed with an apparent association constant of 3.844 × 10^3 L·mol^-1. Based on the enhancement of the fluorescent intensity of gemfibrozil, a spectrofluorimetric method for the determination of gemfibrozil in bulk aqueous solution in the presence of β-CD was developed. The linear range was 3.30 ng·mL^- 1 -6.00 ug·mL^-1 with the detection limit of 0.980 ng·mL^-1. There was no interference from the excipients normally used in tablet composition and the serum main compositions. The proposed method was then successfully applied to the determination of gemfibrozil in capsules and serum.     

Analysis of Vitamin K3 by a Fluorescent Spectroelectrochemistry Method

A simple and sensitive spectroelectrochemistry method for the determination of vitamin K 3 was developed by combining electrolysis and fluoremetry. This method was based on that vitamin K 3 was reduced at a glassy carbon electrode, and its product with characteristic fluorescence at 420 nm was determined with excitation wavelength at 309 nm. Under optimized electrochemical reaction conditions and fluorescent experiment parameters, the fluores-cence intensity was proportional to the concentration of vitamin K 3 in a range from 3.50×10 ?7 to 1.05×10 ?5 mol/L with a correlation coefficient of 0.9991, and detection limit was estimated to be 7.50×10 ?8 mol/L at a signal/noise ra-tio of 3. The relative standard deviation was less than 4.3%(n=5) and the recovery was in a range of 97%―105% for the determination of vitamin K 3 in pharmaceutical preparations. The result is satisfactory for the determination of vi-tamin K 3 as comparison to that from HPLC method.     

高效液相色谱法测定间乙酰氨基苯胺中杂质含量

An HPLC method for determination of l,3-diaminobenzene and N,N'-diacetyl-l,3-diaminobenzene in m-aminoacetanilide was developed.The column used was μ-Bondapak C_(18) with UV detector at 239 nm. The mo-bile phase was methanol-phosphate buffer solution(35 : 65, pH 6.5).The determination was based on the ex-ternal standard method.In the concentration range of l～15μg/mL calibration curves were linear.     

Indirect Flow Injection Chemiluminescence Method for the Determination of Tetracycfines Using Cu（]I） as a Probe Ion

This paper reported an indirect flow injection chemiluminescence （FI-CL） method for the determination of the drugs tetracycline （TC）, chlortetracycline （CTC） and oxytetracycline（OTC） using Cu（ Ⅱ ） as a probe ion. The CL reaction was induced on-line and after injection of the sample the negative peaks appeared as a result of complexation. The method was applied to the determination of TCs in pharmaceuticals and human urine with recoveries in the range95-105%.     

Studies on the Interaction of Beryllon Ⅲ with Proteins by Voltammetric Technique and its Application

A new quantitative determination method of proteins using beryllon Ⅲ by voltammetric technique was developed in this paper. In pH 3.5 Britton-Robinson (B-R) buffer solution, beryllon Ⅲ can bind with human serum albumin (HSA) to form an electro-inactive supermolecular complex. Beryllon Ⅲ has a well-defined voltammetric reduction peak at -0.38 V (vs. SCE) and the addition of protein in this solution can cause the decrease of the reductive peak current. Based on the decrease of the reduction peak current, a new electrochemical method for the determination of HSA was established with linear range of 1.0-40.0 mg/L and the detection limit of 1.0 mg/L. This method is further applied to the determination of real sample of healthy human serum.     

顶空气相色谱法测定香水中的甲醇

In this paper. headspace GC was used to determine methanol in perfume. Separation was performed on a GDX-201 column. 2m×3mm i.d. at 150℃. The characteristics of this method are sensitive. accurate and with less interference. This new method can be used for determination of methanol in cosmetics.