Flow Injection Chemiluminescence Analysis of Diphenhydramine Hydrochloride and Chlorpheniramine Maleate

Abstract

A new chemiluminescence (CL) method, using flow injection, is described for the determination of diphenhydramine hydrochloride and chlorpheniramine maleate. The method is based on the restraining effects on the CL reaction of luminol‐potassium ferricyanide in alkaline solutions. The various experimental parameters affecting the chemiluminescence intensity were studied carefully and incorporated into the procedure. The method allows the determination of 1.0–100 µg mL^?1 diphenhydramine hydrochloride and 0.1–10.0 µg mL^?1 chlorpheniramine maleate. The detection limits of the method are 0.3 µg mL^?1 for diphenhydramine hydrochloride and 0.02 µg mL^?1 for chlorpheniramine maleate. The method was successfully applied to the determination of diphenhydramine hydrochloride and chlorpheniramine maleate in pharmaceutical preparations.     

高效液相色谱法测定片剂中的盐酸舍曲林及有关物质的含量

目的:建立盐酸舍曲林片含量及有关物质测定的高效液相色谱方法。方法:色谱柱为Diamonsil C_(18) (4.6mm × 200mm,5μm);流动相为甲醇-0.2%三乙胺溶液(用磷酸调到pH4.0) (60:40),流速1.5mL/min;检测波长225nm。结果:进样量在2.49～19.94μg范围内,与峰面积线性关系良好,平均回收率为99.55%,RSD为0.60%(n=9)。结论:该方法简单、快速、准确,重现性及专属性好,可用于盐酸舍曲林片的质量控制。     

Spectrofluorometric determination of ascorbic acid using thiamine and potassium ferricyanide

A simple and sensitive spectrofluorometry method for the determination of ascorbic acid was reported. In alkaline solution, the nonfluorescent thiamine was oxidized by potassium ferricyanide and formed the fluorescent thiochrome with an excitation maximum at 367?nm and an emission peak at 441?nm. However, the fluorescence intensity gradually decreased in the presence of ascorbic acid. The decreased fluorescence was linearly dependent under the optimum conditions with the concentration of ascorbic acid from 0.086–1.5?µmol?L^?1 with a correlation coefficient of 0.9996. The detection limit of 0.026?µmol?L^?1 was lower than many other methods. Additionally, the mechanism underlying the enhancement and quenching of this method was discussed. The protocol was used to determine ascorbic acid in tablets and juice with satisfactory results.     

Rapid and Highly Sensitive Method for Protein Determination in Biological Samples with m‐Nitrophenylfluorone‐Mo(VI) Complex as a Spectral Probe

Abstract

A simple, rapid, highly sensitive, and selective method for detecting protein in biological samples has been developed, which is based on the interaction between protein and m‐nitrophenylfluorone‐Mo(VI) complex as a spectral probe. The optimum condition for the reaction is investigated. Bovine serum albumin (BSA) obeys Beer's law up to 10 µg · mL^?1, having a molar absorption coefficient of 8.51×10⁶ L · mol^?1 · cm^?1 at 535 nm. Many amino acids and metal ions do not interfere. The results of determination for biological samples are comparable to those obtained by the Bradford method. Meanwhile, the binding number is also determined.     

A Multiplexed Four Channel On-Line Iodine Monitor

Abstract

A robust autonomous system is described for the spectrophotometric determination of aqueous elemental iodine in multiple flowing process streams. The quantitative methodology uses characteristic absorbance at 460 nm, corrected for baseline drift using absorbance at 600 nm. Linear dynamic ranges of 0.2 - 25 mg/L, 0.4 - 45 mg/L, and 2 - 250 mg/L have been attained using path lengths of 1 cm, 5 cm, and 10 cm respectively. The multiplexed iodine monitor has proven capable of continuous operation for periods of up to eighteen months.     

Fluorescent determination of trinitrotoluene with bovine serum albumin mediated enhancement of thioglycolic acid capped cadmium selenium quantum dots

Abstract

Here, a spectroscopic investigation of the interaction between bovine serum albumin protein and thioglycolic acid capped cadmium selenide (CdSe) quantum dots is presented. Luminescent water-soluble CdSe quantum dots were synthesized at room temperature by a one-step proctocol. Selenium powder and thioglycolic acid were used as the precursor and stabilizer, respectively. The synthesized thioglycolic acid capped CdSe quantum dots were activated by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide treatment and conjugated with bovine serum albumin protein. The fluorescence signal of CdSe quantum dots was enhanced proportionally with the bovine serum albumin concentration from 0.25 to 5?µg/mL. This nano-bioconjugate was employed for the determination of trinitrotoluene with a detection limit of 5.65?ppm trinitrotoluene across a linear range of 4.4?×?10^?6 M to 35.2?×?10^?6 M.     

Mercurimetric and Polarographic Determination of Captopril

ABSTRACT

Two different methods have been applied for the determination of captopril, namely,(i) a direct mercurimetric method using standard mercuric nitrate solution and diphenyl carbazone as an end-point indicator (ii) a differential pulse (DP50) polarographic method based on the measurement of the polarographic current at the peak potential of - 0.25V vs. Ag/AgCl (Kcl Sat.) reference electrode using acetate buffer of pH U.6 as a supporting electrolyte containing 0.01% w/v gelatin as a maximum suppressor. The accuracy obtained for the mercurimetric method is 99.8±0.7% and 100.2±1.3% for the authentic captopril and its tablets respectively. For the polarographic method, the linearity between current and concentration holds for the concentration range 2 to 45 ppm under the experimental conditions employed with an accuracy of 99. 4±0.8% and 99.9±1.9% for the authentic captopril and its tablets respectively.     

Rapid and Sensitive Determination of Nucleic Acids by Enhanced Resonance Light Scattering Spectroscopy of Tetraphenyl Porphyrin Cobalt(II)Chloride

Abstract

A novel probe, tetraphenyl porphyrin Cobalt(II)chloride (CoTPPCl), was first developed for the determination of nucleic acids at a nanogram level by a resonance light scattering (RLS) technique. Under optimum conditions, the weak RLS signal of CoTPPCl was enhanced greatly by nucleic acids at 444.0 nm; the enhanced RLS intensity is proportional to the concentration of nucleic acids in the range of 0.05–3.5 mg L^?1 for calf thymus DNA and 0.03–4.2 mg L^?1 for fish sperm DNA. The detection limits (3δ) are 3.5 ng mL^?1 for calf thymus DNA and 4.5 ng mL^?1 for fish sperm DNA, respectively. The results show that determination of nucleic acids with CoTPPCl as a probe is much more sensitive than with α, β, γ, δ‐ tetrakis[4‐(trimethylammoniumyl)phenyl]porphine (TAPP). Synthetic samples and plasmid DNA extracted from K‐12‐HB101 colt were determined with satisfactory results.     

Spectrophotometric Determination of Silicon in Rice and Alloy Steel Samples

Abstract

In the medium of 0.128 mol/L nitric acid and 0.450 mol/L sulfuric acid, silicon(IV) and ammonium molybdate form molybdosilicate blue blue complex in the presence of ascorbic acid. The maximum absorption wavelength of the complex locates at 810 nm. The apparent molar absorptivity is ε_810 nm = 3.18 × 10⁴ L · mol^?1 · cm^?1. Beer's law is followed over the range of 0 ～ 1.0 µg/mLof silicon(IV). The present method has been successfully applied to the determination of silicon in rice and alloy steel samples.     

Resonance Rayleigh Scattering of K2Zn3[Fe(CN)6]2 Nanoparticles and its Application for the Determination of Vitamin C

Abstract

In Britton-Robinson buffer medium, (pH 4.43), potassium ferricyanide (K₃[Fe(CN)₆]) could react with vitamin C (VC) to produce potassium ferrocyanide (K₄[Fe(CN)₆]), which further reacted with Zn²⁺ to form potassium zinc hexacyanoferate K₂Zn₃[Fe(CN)₆]₂ nanoparticles. The shapes and diameters of the K₂Zn₃[Fe(CN)₆]₂ nanoparticles have been observed with transmission electron microscopy, which showed the shapes of these nanoparticles was cubic and their average sizes were about 50 nm in the presence of 2.0 × 10^?5 mol L^?1 VC. The characteristics of resonance Rayleigh scattering (RRS) spectra of this reaction have been studied. The optimum reaction condition for the determination of VC has been investigated. It was found that the RRS intensity of the system at the RRS peak of 363.4 nm was proportional to the VC concentration in the range of 4.0?80.0 µmol L^?1, and the detection limit (3σ) for VC was 0.075 µmol L^?1. A novel and simple RRS method for the determination of VC based on the formation of K₂Zn₃[Fe(CN)₆]₂ nanoparticles has been established.     

离效液相色谱法测定尼群地平的含量

本文采用液相色谱法,用ODS色谱柱(20Omm×4.6mm,5μm),以甲醇:水(70:30)为流动相,流速1.0mL/min,检测波长237nm,室温操作,采用外标法对尼群地平含量进行测定,能有效分离杂质,方法简便快速,结果准确可靠。     

Determination of tetracyclines by novel singlet-oxygen mediated cerium(IV) chemiluminescence

Novel chemiluminescence mechanisms of cerium(IV) and five tetracyclines in the absence and presence of Tween 80 are reported. The role of tetracyclines in the present chemiluminescence system was studied in detail by ultraviolet spectra and the singlet oxygen ¹O₂ probe 2-methyl-6-(4-methoxyphenyl)-3, 7-dihydroimidazo[1,2-a]-pyrazin-3-one hydrochloride. It is the first report that cerium(IV) reacted with tetracyclines producing singlet oxygen ¹O₂ after breaking the organic skeleton and decomposition of peroxyacetic acid in the absence of the surfactant Tween. Furthermore, by examining the effects of sodium azide and the chemiluminescence spectra, the results indicated that the maximum chemiluminescence emission at approximately 480?nm was due to dimer emission of singlet oxygen ¹O₂ from the reaction between cerium(IV) and tetracyclines as well as the reaction of cerium(IV) and Tween 80, respectively. Moreover, the chemiluminescence signals were unaffected when the reaction was performed under anaerobic condition, indicating that dissolved oxygen was independent of this system. Under the optimal conditions, the analytical characteristics and parameters of the cerium(IV)-Tween 80-tetracyclines chemiluminescence system were investigated. The present method was successfully employed for the determination of tetracyclines in milk.     

Electrochemical Behavior of Epinephrine at Two‐Component Self‐Assembled Monolayer of meso‐2,3‐Dimercaptosuccinic Acid and Penicillamine on Gold Electrode

Abstract

A mixed, self‐assembled monolayer (SAM) of meso‐2,3‐dimercaptosuccinic acid (DMSA) and penicillamine (PCA) was prepared on a gold electrode. The mixed SAM of DMSA and PCA, for which the volume ratio of DMSA:PCA was 2:1, showed an obvious electrochemical activity for the oxidation of epinephrine (EP). In the phosphate buffer (pH 7.7), a sensitive oxidation peak was observed at 0.213 V on the DMSA and PCA modified Au electrode. The peak current was proportional to the concentration of EP in the range between 5.0×10^?6 and 8.0×10^?4 mol L^?1. For the cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods, the detection limits were 3.9×10^?7 and 2.5×10^?7 mol L^?1, respectively. The reaction mechanism has been primarily discussed. The electrode reaction of EP was an irreversible process with two electrons and two protons transfer at the SAM gold electrode. The SAM gold electrode was applied to the determination of EP in epinephrine hydrochloride injection samples with satisfactory results.     

DETERMINATION AND SEPARATION MECHANISM OF ACRYLAMIDE BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

High-performance liquid chromatography using the negative peak method was developed for the determination and separation of acrylamide in food with methanol-water containing a background reagent of 0.01 mmol L^?1 5-sulfosalicylic acid (15/85, v/v) as the mobile phase with an ultraviolet-visible detector (λ_sig = 320 nm, λ_ref = 210 nm). The method was simple, the correlation coefficients exceeded 0.9990, and the limit of detection for acrylamide was 0.07 μg kg^?1. The concentrations of acrylamide in food were between 81 and 910 μg kg^?1. The recoveries were greater than 81.0% and the relative standard deviation was between 0.24 and 3.6%. The results showed that this method was suitable for the determination of acrylamide in food.     

Determination of R‐Deprenyl using a Maltodextrin‐Based Enantioselective,Potentiometric Membrane Electrode

Abstract

The enantioselective, potentiometric membrane electrode (EPME) based on maltodextrin with dextrose equivalence (DE) 16.5–19.5 is proposed for the assay of R‐deprenyl. The linear concentration range for the proposed electrode is 10^?10?10^?3 mol L^?1. The slope of the electrode is 53.1 mV per decade of concentration. The detection limit is 3.6×10^?11 mol L^?1. The proposed electrode could be reliably employed for the assay of R‐deprenyl raw material and its pharmaceutical formulation, Lentogesic tablets.     

Characterization and application of lornoxicam,europium(III), and lysozyme fluorescence

A novel and sensitive spectrofluorimetric method was developed for the determination of lornoxicam. The method was based on the fluorescence enhancement of europium(III) by formation of a ternary complex with lornoxicam in the presence of lysozyme as the co-ligand. The fluorescence signal for the lornoxicam-europium (III)-lysozyme system was monitored at an excitation wavelength of 620 nm and an emission wavelength of 390 nm. The parameters affecting the fluorescence intensity were optimized systematically and under these conditions the signal was directly proportional to the concentration of lornoxicam from 9.0 × 10^?5 to 1.0 × 10^?2 µg · mL^?1. The detection limit was 2.7 × 10^?5 µg · mL^?1. The relative standard deviation for thirteen replicate measurements of 1.0 × 10^?3 µg · mL^?1 lornoxicam was 1.8%. This method was employed for the determination of lornoxicam in pharmaceutical formulations and biological fluids. The mechanism of fluorescence for the lornoxicam-europium(III)-lysozyme system was discussed.     

Polarographic Reduction Wave of Hemoglobin and its Application to Micro‐Determination

Abstract

An adsorptive reduction wave of hemoglobin at about ?1.43 V (vs. SCE), in phosphate buffer solution, pH 6.8, was found by using single sweep polarography. Based on this wave, a simple, rapid, and reliable polarographic method for hemoglobin determination was developed. The wave height is linearly proportional to the concentration of hemoglobin in the range of 1.0–28 mg/L (correlation coefficient 0.997). The detection limit is 0.5 mg/L. Serum albumin, common amino acids, and metal ions present no interference with the hemoglobin determination.

The proposed method was applied to the determination of hemoglobin in human blood samples with satisfactory results. The polarographic wave is attributed to the direct reduction of hemoglobin at the dropping mercury electrode. The new method could be useful in biochemical, clinical, and pharmaceutical analysis.     

Determination of (S)-(+)-Ibuprofen Using Enantioselective,Potentiometric Membrane Electrodes Based on Macrocyclic Antibiotics

Abstract

The enantioselective, potentiomeric membrane electrode based on vancomycin and teicoplanin modified with acetonitrile were proposed for the assay of (S)-(+)-ibuprofen. The linear concentration ranges for the proposed enantioselective membrane electrodes were 10^?2 to 10^?4 and 10^?2 to 10^?6 mol/Lfor electrodes based on vancomycin and acetonitrile modified teicoplanin, respectively, with slopes of 58.5 and 57.0 mV/decade of concentration, respectively. The proposed electrodes could be employed reliably for the assay of (S)-(+)-ibuprofen raw material and in its pharmaceutical formulations, Myprodol capsules and Nurofen tablets. The surfaces of the electrodes are stable and easily renewable by polishing on alumina paper.     

PVC Membrane Sensor for Potentiometric Determination of Atropine in Some Pharmaceutical Formulations

Abstract

The construction and general performance of a novel potentiometric membrane sensor for determination of atropine has been developed. It is based on the formation of the ion association complex of the atropinium cation with phosphotungstate counter anion as electroactive material dispersed in a PVC matrix, β‐Cyclodextrin and o‐nitrophenyl octyl ether serve as a plasticizer. The sensor shows a fast, stable, near Nernstian response for 1×10^?2 M to 1×10^?6 M atropine at 25°C over the pH range of 3–8 with a cationic slope of 51±0.5 mV/decade. The lower detection limit is 8×10^?7 M and the response time is 20–45 sec. Selectivity coefficients of atropine, relative to a number of interfering substances, were investigated. There are negligible interferences caused by most of the studied cations, anions, and pharmaceutical excipients. The direct determination of atropine shows an average recovery of 98.6% and a mean relative standard deviation (RSD) of 1.6% at 100 µg/mL. The results obtained by determination of atropine in some formulations (atropine injection and eye drops) are favorably comparable with those obtained by the British Pharmacopoeia method. The developed membrane electrode has been used as end point indicator electrode for some potentiometric titrations.     

Development of Sulfide‐Selective Optode Membranes Based on Immobilization of Methylene Blue on Optically Transparent Triacetylcellulose Film

Abstract

The development of reversible sulfide‐selective optode membranes, based on immobilization of methylene blue (MB) on optically transparent triacetylcellulose film, is described. The sensing scheme of the sulfide‐selective optode membranes is based on the decreasing absorbance of the membrane at 654 nm in the presence of sulfide, which can be related to the sulfide concentration in solution. The dynamic working range, detection limit, sensitivity, selectivity, and effect of pH are discussed in detail.

Under optimum experimental conditions, the membrane system shows a calibration response range from 3.1×10^?5 to 6.1×10^?4 M in a phosphate buffer of pH 7.5. Typical response times in the samples are 15–20 min. The lifetime of the system was about 30 days, with a relative standard deviation of <2%. The sensing membrane showed a good selectivity to sulfide over other anions. The optode membrane was applied to the determination of sulfide in real samples.