Simultaneous High-Performance Liquid Chromatographic Assay of Acetaminophen,Acetylsalicylic Acid,Caffeine, and D-Propoxyphene Hydrochloride

Abstract

A reversed phase high-performance liquid chromatography (HPLC) method for simultaneous measurement of acetaminophen (I), acetylsalicylic acid (II), caffeine (III) and d-propoxyphene (IV), using phenacetin (V) as an internal standard was developed. Using a 6.5 μ C-8 reversed phase column (RPP) with a mobile phase consisting of 0.01M sodium acetate solution: methanol (85:15%) at pH 4.1 enabled the Chromatographic separation of the four components in about 12 min. Quantitation was achieved by measuring the peak height ratio of each component relative to the internal standard. the validity of the developed method was tested by analyzing laboratory-prepared mixtures containing the four components in various proportions. Assay precision and sensitivity have been established for each component. the developed method proved to be stability-indicating as it can be applied to monitor salicylic acid as a degradation product in acetylsalicylic acid samples.     

Microcoulometric Determination of Sulfur and Chlorine by Combustion and Nitrogen by Hydrogenolysis

Abstract

The design of an improved open microcombustion tube and experimental conditions for the rapid, accurate and precise determination of sulfur and chlorine by microcoulometry are described. The design and operating conditions for a catalytic hydrogenolysis tube and scrubber tube for acid removal are also presented for the determination of nitrogen. Examples of the application of the above methods for these elements in petroleum and petrochemicals are presented.     

Zero-Crossing Derivative Spectrophotometric Determination of Mercury(II) And Palladium(II) with 5-(3,4-Methoxyhydroxyphenylmethylene)-2-thioxo-1-3-thiazolidine and Cetyltrimethylammonium Bromide

Abstract

A method is proposed for the simultaneous determination of mercury(II) and palladium(II) by first-derivative spectrophotometry based on the absorption spectra of their complexes with 5-(3,4-Methoxyhydroxyphenylmethylene)-2-thioxo-1,3-thiazolidine [5-(3,4-methoxyhydroxybenzylidene) rhodanine]. Zero-crossing measurement technique is found suitable for the measurement of the first-derivative value at the specified wavelengths. Mercury(II) (0.4-1.4 μg ml^?1) and palladium(II) (0.08 - 1.8 μg ml^?1) in different ratios have been determined simultaneously. A critical evaluation of the proposed method is performed by statistical analysis of the experimental data.     

Fluorimetric determination of trace amounts of aluminium and gallium with salicylaldehyde-1-phthalazinohydrazone

Fluorimetric determinations of aluminium and gallium, based on the formation of fluorescence complexes between Al(III) or Ga(III) and salicylaldehyde-1-phthalazinohydrazone, SAPhH, are proposed. The Al(III)-SAPhH complex exhibits fluorescence with maximum emission at 475 nm when excited at 414 nm; the Ga(III)-SAPhH chelate has emission and excitation maxima at 480 and 410 nm, respectively. For both determinations the range of application is 10–100 ng/ml. Aluminium has been determined in waters, and gallium in aluminium and nickel alloys.     

Spectrophotometry Determination of Molybdenum with N-Cyanoacylacetaldehyde Hydrazone

N-cyanoacylacetaldehyde hydrazone (CAAH), which is a laboratory synthetic reagent, is proposed as a new reagent for spectrophotometry determination of microamounts of molybdenum at λ_max 790 nm. The reagent forms 1:1 blue coloured complex with molybdenum (VI) in phosphoric acid solution. The stable blue colour is obtained finally after changing from yellow to green. The colour development depends on temperature, time and concentration of phosphoric acid. This reagent is applied for the determination of molybdenum in steel alloys and the results are satisfactory.     

Simultaneous Determination of Copper (II) and Mercury (II) by Using a Zero-Crossing Method

Abstract

The application of a zero-crossing method to the simultaneous determination of copper (II) and mercury (II) with methylethylenediaminetetraacetic acid (MEDTA) is described. The procedure does not require equations to be solved, and it is suitable for concentrations of 0.008–0.036 mg ml^?1 of copper and 0.025–0.300 mg ml^?1 of mercury. The main interferences, both anionic and cationic, were easily eliminated. The method was applied to different aqueous matrices. It was compared with an atomic absorption spectrophotometry method (AA) and good results were obtained.     

Simultaneous Square‐Wave Voltammetric Determination of Paracetamol,Caffeine and Orphenadrine in Pharmaceutical Formulations Using a Cathodically Pretreated Boron‐Doped Diamond Electrode

An electroanalytical method for the simultaneous determination of paracetamol (PAR), caffeine (CAF), and orphenadrine (ORPH) using the square‐wave voltammetry (SWV) and a cathodically pretreated boron‐doped diamond electrode was developed. The method exhibits linear responses to PAR, CAF, and ORPH in the concentration ranges 5.4×10^?7–6.1×10^?5 M, 7.8×10^?7–3.5×10^?5 M, and 7.8×10^?7–3.5×10^?5 M, respectively, with detection limits of 2.3×10^?7 M, 9.6×10^?8 M, and 8.4×10^?8 M, respectively. The proposed method was successfully applied in the simultaneous determination of these analytes in pharmaceutical formulations.     

Indirect polarographic microdetermination of chlorine or bromine in organic compounds

A polarographic method for the microdetermination of chlorine or bromine in organic compounds is based on oxygen-flask combustion followed by an exchange reaction of chloride or bromide with excess of solid silver chromate, and polarographic determination of the chromate liberated. The method has been applied satisfactorily to a wide range of chlorine or bromine organic compounds with a coefficient of variation not exceeding 1%.     

Kinetic determination of codeine in pharmaceutical preparations

A kinetic method for the determination of codeine, based on its inhibitor action on the catalytic decomposition of hydrogen peroxide by cobalt(II), is presented. It has been found that the effect of codeine is most pronounced in the presence of 5% v/v ethylene glycol. The reaction is followed photometrically. Codeine can be determined in concentrations ranging from 0.80×10^–5 M to 2.4×10^–5 M. The method has been applied to the determination of codeine in pharmaceutical preparations.     

Simultaneous Ultraviolet Spectrophotometric Determination of Nitrate and Nitrite in Water

Abstract

A rapid and accurate method for the direct simultaneous determination of nitrate and nitrite is proposed. The method is applied to the determination of nitrate and nitrite in rainwater and wastewater without preliminary separation. The determinations are performed by a CPA matrix method with ultraviolet spectrophotometric detection. The results obtained are in agreement with those obtained by conventional methods for the determination of nitrate and nitrite.     

A dot-blot test using gold colloid cluster technology as a miniaturizable alternative to ELISA and hapten inhibition tests

A novel miniaturizable method to quantify antigens is described in form of a cluster linked immunosorbent assay (CLISA), using inexpensive nitrocellulose (NC) membranes as a support for dot-blotting the antigens. Antibodies for detection are labeled with gold-colloid clusters (GCC). After blocking of the membrane with non reacting protein and application of the GCC-labeled antibodies the signal is detectable by visual colorimetry and can be compared to a color scale prepared from a dilution series of known sample concentrations. The color reaction product is stable for a very long time and does not fade. The sensitivity of the method is comparable to that of ELISA if not better and furthermore needs only small amounts of antibody for detection or for GCC-labeling. This method is an alternative to the use of expensive enzyme-conjugated antibodies for a number of applications, such as tracking of antibodies during purification or hapten inhibition tests. Correspondence: Haifa Al-Dubai, Max F. Perutz Laboratories, Department of Biochemistry, University of Vienna, 1030 Vienna, Austria.     

五氯苯酚测定方法研究进展

介绍了目前国内五氯苯酚常用的分析方法,对每种分析方法的原理、操作条件、检测限、线性范围及应用对象作了较为详细的论述.指出吸光光度法操作简单,仪器比较普及,但五氯苯酚吸收带较宽,分辨率低,共存有机物影响较大,其应用受到限制.高效液相色谱法样品无需气化,也不需衍生化,是高沸点、热稳定性较差的五氯苯酚较理想的分析方法.乙酰衍生化、毛细管柱分离、电子俘获检测器检测是目前测定五氯苯酚最常用的气相色谱法.吹扫捕集技术、固相微萃取技术以及质谱检测技术在气相色谱分析中的应用有效提高了测定五氯苯酚的准确度和灵敏度.离子选择性电极法测五氯苯酚仍处于研究阶段.     

自来水中余氯测定之TMB配制探讨

对TMB的配制的介质浓度，配制方法及其助溶温度等诸因素进行了探讨，拟定了自来水中余氯测定的TMB溶液配制的具体方法，助溶温度和介质酸度等，解决了生活饮用水卫生规范中测定水中余氯用TMB显色无法与标准色阶进行比色的实际问题。完全能满足日常生产的现场检测的需要。     

Kinetic determination of cysteine and thiosulphate by inhibition of Hg(II) catalyzed ligand substitution reaction

The sulphur containing inhibitors (I), cysteine (Cys) and sodium thiosulphate (THS), have been found to inhibit Hg(II) catalyzed exchange of cyanide in hexacyanoferrate(II) by nitroso-R-salt (NRS). The inhibitory effect of both the ligands are attributed to their binding tendencies with Hg(II) leading to the formation of catalyst-inhibitor (C-I) complex. The reactions have been followed spectrophotometrically in aqueous medium at 720 nm by noting the increase in absorbance of the green colour product, [Fe(CN)₅NRS]³⁻ at pH 6.50 ± 0.02, temp 25.0 ± 0.1 °C and ionic strength (μ) 0.1 M (KNO₃). A most plausible mechanistic scheme involving the role of analytes (inhibitors) has been proposed. The values of equilibrium constants for complex formation between catalyst-inhibitor (K_CI), catalyst-substrate (K_S) and Mechaelis-Menton constant (K_m) have been computed from the kinetic data. The linear calibration curves have been established between absorbance and inhibitor concentrations under specified conditions. Cys and THS have been determined in the range 1-5 × 10^− 7 M and 4.9-16.9 × 10^− 7 M respectively. The detection limits have been computed to be 1 × 10^− 7 M and 4.9 × 10^− 7 M for Cys and THS, respectively.     

水中溶解氧的测定

对近年来有关水中溶解氧的各种主要测定方法作了简介和评述,并重点介绍了传感器法的现状和发展趋势。     

Determination of cadmium and lead in cetacean Dolphinidae tissue from the coast of Bahia state in Brazil by GFAAS

In the present study, cadmium and lead in the muscle, lung, liver and kidney of dolphins (Sotalia guianensis and Stenella clymene) of the Bahia coast in the northwest of Brazil were determined by graphite furnace atomic absorption spectrometry. Samples were digested using a diluted oxidant mixture (HNO₃ + H₂O₂) with a microwave heating program performed in five steps. The optimized temperatures and chemical modifier for the pyrolysis and atomization were 700 °C, 1400 °C and Pd plus Mg for Cd, and 900 °C, 1800 °C and NH₄H₂PO₄ for Pb, respectively. Characteristic masses and limits of detections (n = 20, 3σ) for Cd and Pb were 1.6 and 9.0 pg and 0.82 ng g^− 1 and 0.50 ng g^− 1, respectively. Repeatability ranged from 0.87 to 8.22% for Cd and 4.31 to 8.09% for Pb. The found concentrations presented no statistical differences at the 95% confidence level when compared with the ICP OES methods. Addition and recovery tests were also performed and the results ranged between 87 and 112% for both elements. Samples of cetacean Dolphinidae (S.guianensis and S.clymene) were analyzed, and the higher concentrations ranged from 0.09 to 46.2 µg g^− 1 for Cd and 0.04 to 0.47 µg g^− 1 for Pb in liver, and from 0.133 to 277 µg g^− 1 for Cd in the kidney.     

Determination of Osmium(VIII) and Palladium(II) in Mixtures by Derivative Spectrophotometry

Abstract

A sensitive method for the simultaneous determination of osmium(VIII) and Palladium(II) (up to 15 μ9/ml of Os and 11 μ9/ml of Pd) in mixtures, by first and second derivative spectrophotometry, using allyl thiourea as reagent, is described.

A statistical analysis of the results is reported.     

A simple,sensitive, and specific HPLC amperometric screening method for trace levels of sulphonamides in liver,kidney, and muscle tissues

Summary A simple, sensitive and specific method for the analysis of the residues of sulphonamides in liver, kidney, and muscle tissues is described. The method is based on a simple extraction step, separation on a RP-C₂ column and amperometric detection at +1.10 V. Recoveries were calculated with the aid of sulphamerazine as internal standard. The detection limit of the proposed method is 10 ng/g.     

Selective Enzymatic Determination of L-Phenylalanine and Phenyl-Pyruvate

Abstract

A simple enzymatic end point method for the determination of L-phenylalanine and 3-phenylpyruvate has been developed. The assay is based on the spectrophotometry determination of NADH formed or degraded in the reaction catalyzed with Thermoactinomyces intermedins phenylalanine dehydrogenase. This method enables the simple and selective determination of L-phenylalanine and 3-phenylpyruvate based on the high substrate specificity of the enzyme. The assay is sensitive in the range of 0.015?0.15 umol of L-phenylalanine and 3-phenylpyruvate.     

Determination of C-atom density downstream an Ar-CH4 rf plasma torch

Nitrogen, oxygen, and carbon atoms have been detected by optical emission spectroscopy in a common flowing post-discharge of an Ar-x CH₄ rf plasma torch and an Ar-2%N₂ microwave discharge. Gas temperature as determined from CN and N₂ rotational svstems is 3200 ± 200 K in the rf torch and 700 ± 100 K in the post-discharge at a time 3 X10^–2 s after the rf plasma torch. From the intensities of the N₂ 1st positive system, of NO, and of CN violet hands, the atom densities have been determined as 2 X 10¹⁶ cm³ for N, 10¹⁵ cm³ for O, and 6 X 10¹² cm³ for C in the post-discharge at p=650 torr, with 10³ of CH₄ in the Ar torch.