Isotachophoretic determination of 3-methylhistidine.

A capillary isotachophoretic (cITP) method to determine the concentration of 3-methylhistidine (3-MeHis) in meat and meat products is described. A clear separation of the 3-MeHis from histidine, 1-methylhistidine and other components of acidic sample hydrolyzate was achieved within 20 min. Method characteristics (linearity, accuracy, precision and detection limit) were determined. Low laboriousness, sufficient sensitivity and low running cost are the important attributes of cITP method. The developed method was successfully applied to analyses of real samples and used for the determination of lean meat content in meat and meat products.     

Utilisation de la Vanilline et de Son Oxime Comme Etalon Interne Dans les Dosages des Acide-Phenols par Chromatographie Liquide: I. Application au Dosage de l'Acide Homovanillique Urinaire

Abstract

An HPLC method of standardization for acid-phenol (especially HVA) determination in urine is proposed. Urine spiked with vanillal is extracted with ethyl acetate. Exact area of the vanillal chromatographic peak is measured by difference beetwen two chromatograms : one of the urinary extract and one of the same extract submitted to oximation reaction. The method allows reliable internal standardization even when various urinary compounds are superposed to vanillal on the chromatogram. Correlation with CPG for HVA determination is excellent.     

Extraction Rapide de la Cafeine Urinaire Sur Cartouche C18 Et Dosage Par Chromatographie Gazeuse

Abstract

A rapid method for urinary caffeine extraction on C₁₈ cartridge before GC determination is proposed in view of doping controls in sport. The choice of the standard and of the analytical procedure has been directed by the necessity of rapid determination.

Caffeine extraction on C₁₈ reverse-phase is achieved with a good efficiency (recovery : 98 %, CV = 3 %), so that use of an internal standard was not found necessary. Amobarbital was chosen as internal standard in GC because of several advantages : retention time, thermal stability, interesting properties in mass fragmentometry.     

Capillary Electrophoresis as A Diagnostic Tool: Determination of Biological Constituents Present in Urine of Normal and Pathological Individuals

Abstract

A quantitative ultraviolet detection method for the determination of urinary metabolites is described using capillary zone electrophoresis. The determination of these metabolites is simple, fast. reproducible and utilizes very small amounts of sample. This method is linear between 1.0 × 10^?4 and 1.0 × 10^?2 M for creatinine and between 1.0 × 10^?1 and 1.0 M for urea. The ultraviolet method shows detection limits for creatinine in the picogram (femtomol) range, and for urea in the nanogram (picomol) range.     

Enzymatic Determination of Urinary Total 17β-Hydroxysteroids

Abstract

An enzymatic determination of urinary total 17β-hydroxysteroids is described. The principle of the method is as follows: after hydrolysis with β-glucuronidase and solvolysis, the ethyl acetate layer, which is washed with alkaline solution and water, is transferred to two test tubes, then each of them is evaporated. To one test tube is added 3β,17β-hydroxysteroid dehydrogenase (EC 1.1.1.51, from P. testosteroni), NAD⁺, 2-ρ-iodophenyl-3-ρ-nitrophenyl-5-phenyltetrazolium chloride (INT), and diaphorase (EC 1.6.99.2, from C. kluyveri) for determination of total 3β,17β-hydroxysteroids. To another test tube is added 3β-hydroxysteroid oxidase (EC 1.1.3.6, from B. sterolicum) for determination of total 3β-hydroxysteroids. The value of 17β-hydroxysteroids is calculated by subtracting the value for 3β-hydroxysteroids from the value for the 3β,17β-hydroxysteroids.     

The Rapid Determination of Neopterine in Human Urine by Isocratic High-Performance Liquid Chromatography

Abstract

An isocratic high-performance liquid chromatography method is described for the determination of Neopterine eliminated in human urine, using a μ-Bondapak C₁₈ column (300 × 3.9 mm I.D.) and a strongly polar phosphate buffer (pH 6.2) for elution. This analysis requires only 15 minutes and allows very good reproduc-tibility of retention times. This method is well-suited for automation and routine clinical laboratory in order to quantify human urinary Neopterine in healthy subjects and in subjects with malignant disorders.     

Determination of mitomycin C in urinary bladder tissue by reversed-phase high-performance liquid chromatography

A procedure was developed for the determination of an anticancer drug of mitomycin C (MMC) in urinary bladder tissue samples by reversed-phase high-performance liquid chromatography with spectrophotometric (365 nm) and mass-spectrometric detection with detection limits of 50 and 10 ng/mL, respectively (signal-to-noise ratio = 3). The tissue samples were homogenized and solid-phase extraction was performed on a DSC-18 cartridge. The procedure was used for comparing the effectiveness of the MMC penetration into the urinary bladder tissue by passive diffusion and by intravesical drug electrophoresis. EDMA increases the rate of mitomycin penetration into urinary bladder walls by 3 to 5 times with respect to passive diffusion.     

The Determination of Ioglycamic Acid in Bile and in Urine by High Performance Liquid Chromatography

Abstract

A fast, simple and specific method for the determination of ioglycamic acid in bile and in urine is described. Reversed-phase ion-pair chromatography with methanol-water (67.5: 32.5) in the presence of the counter ion tetrabutyl-ammonium phosphate as the mobile phase separates ioglycamic acid in 5 min at a flow rate of 1 ml/min. Under the same conditions urinary creatinine can be simultaneously determined and may be used as an endogenous internal standard. Bile and urine from a healthy subject were screened for possible metabolites but these are not detected.     

Rapid High Performance Liquid Chromatographic Determination of Ampicillin in Human Urine

Abstract

A rapid, sensitive and specific HPLC assay for the determination of ampicillin in human urine is developed.

Ampicillin was directly measured in human urine at 225 nm using a reversed phase column (Synchropack RP-P) and a mobile phase composed of (1:9 methanol-sodium acetate solution, 0.01 M, pH 4). The analysis required no longer than 10 min. Linear correlation between the peak height ratio of ampicillin to cefoxitin sodium (internal standard) and ampicillin concentration in urine over the range 10–100 μg ml^?1 was obtained. The developed method proved to be advantageous as it monitors ampicillin level in urine. Moreover, the urinary excretion of ampicillin in human subjects after an oral administration of 500 mg ampicillin capsules was established using the proposed method.     

A Novel Protein Assay Method Using Tetraphenylporphin tetrasulfonate (TPPS4)

Abstract

A sensitive protein assay method which involves the reaction of TPPS₄ with protein is described. When protein is added to TPPS₄ solution, an absorption band with the maximum at 488 nm appears and the absorbance is proportional to the concentration of protein. Just Like the Soret absorption of the porphyrin, the new band is very narrow and there is no overlap at all between them, which means the free dyes would not give any background for the detection of the protein-TPPS₄ complexes. A new spectrophotometric method for determination of protein has been constructed and applied to the determination of human plasma protein and urinary protein; The assay using microtiter plates has also been studied.     

Determination of Urinary Oxalate by Ion Chromatography

Abstract

The factors which are important for calcium oxalate renal stone formation may be studie, in vitro, using the constant composition mineralization method (Gaur and Nancollas, Kidney Int., 26, 767 (1984). Since the molar calcium/oxalate rations in vivo are relatively high (normal range, 5–50) the rates of these seeded crystallization reactions at constant supersaturations are markedly dependent upon the concentrations of oxalate ion. Kinetic studies therefore require a rapid and reliable method for the analysis of this ion. A Dionex QIC analyzer incorporating an anion fiber suppressor unit and conductometric detector has been used to develop a method for the determination of urinary oxalate. The eluent, consisting of a mixture of 3.23 × 10^?3 mol L^?1 NaHCO₃ and 2.41 × 10^?3 mol L¹ Na₂CO₃, was used isocratically at a flow rate of 2.2 cm³ min^?1. The 14 min analysis time was considerably shorter than that reported for previous ionchromatographic methods. The minimum detectactable oxalate in urine was 0.11 × 10^?3 mol L^?1 with a RSD of about 10%. The method is especially suitable for monitoring oxalate in urine mineralization experiments.     

Automated Determination of Urinary Polyamines

Abstract

A system for the determination of urinary polyamines by ion exchange chromatography with fluorescence detection is presented. It provides a sensitive and specific assay of putrescine, cadaverine, spermidine and spermine in urine hydrolyzates. An internal standard is used, which makes the automated determination of series of samples easy.     

Simple Determination of Steroid Sulfatase Activity in Enzyme Preparation

Abstract

Simple one tube method for the determination of steroid sulfatase activity in an enzyme preparation or commercially available preparation is described. Principle of the reaction is as follows; dehydroepi-androsterone sulfate (DHEA-S) as substrate is hydrolyzed by the catalysis of sulfatase and DHEA released is determined by the enzymic method using 3β-hydroxysteroid oxidase.     

New Spectrophotometric Method for the Determination of Titanium in Soil and Standard Geochemical Samples

Abstract

In the present communication a simple and rapid spectrophotometric method for the determination of titanium is described. The method is based on the reaction of Ti(IV) with a newly synthesized reagent, 6-(4-nitrophenylazo)-3,4,5-trihydroxy benzoic acid (NATHB), in ethanol medium at pH 3.2 to 4.2. The complex exhibits an absorption maximum at 495 nm and Beer's law is valid over the range of 0.04 – 1.00 μg.ml^?1 Ti. The molar absorptivity is 3.48 × 10⁴ dm³.mole^?1. cm^?1. Most of the foreign metal ions and anions do not produce any colorations with NATHB at selected conditions. Based on these results, a simple and direct spectrophotometric method with high selectivity and sensitivity was proposed. The method has been successfully applied for the determination of titanium in 5 soil and 3 standard geochemical samples.     

Flow Injection Amperometric Determination of Hydrogen Peroxide at Low Level in Aqueous Solution

Abstract

A method is proposed for the flow-injection amperometric determination of hydrogen peroxide. Iodine is generated, by injecting hydrogen peroxide solution into an eluent 0.2 M in potassium iodide and 1 Min sulphuric acid and 5×10^?3M in Mo(VI) and is monitored at a platinum electrode that is being held at 0.1 V versus SCE. the rectilinearity range is from 10^?3?10^?6 M and the method is simple, accurate and compared favourably with the titrimetric method involving starch as indicator.     

Determination of Hg in water and wastewater samples by CV-AAS following on-line preconcentration with silver trap

An online mercury preconcentration and determination system consisting of cold vapor atomic absorption spectrometry (CV-AAS) coupled to a flow injection (FI) method was studied. The method was developed involving the determination of ng/L levels of mercury retained on the silver wool solid sorbent. Experimental conditions such as sample volume, flow rate, stability of the column and effect of foreign ions on the determination of trace amounts of mercury were optimized. The detection limit is 3 ng/L and dynamic range 10–250 ng/L require only 50 mL of sample. The relative standard deviations (RSD) of the determinations are below 4%. The presence of common metal ions, such as K+, Na⁺, Cu²⁺, Pb²⁺, Fe³⁺, Ni²⁺, and Mn²⁺, does not interfere with the measurement of mercury by this method. The method was successfully applied to the determination of mercury in water and wastewater samples.     

Spectrophotometer Determination of Nitrite Using Salbutamol sulphate as a Reagent

Abstract

A simple spectrophotometric method for the trace determination of nitrite (NO^? ₂) is described. Nitrite is reacted with Salbutamal sulphate in acidic medium which gives a yellow colour in alkaline medium (?pH 7) and can be determined in the presence of several cations and anions. Beer's law is obeyed in the range of 1.8 to 27.6 ppm of nitrite with the molar absorptivity 1.8 × 10³ 1 × mole^?1 × cm^?1 at 4l0 nm. The proposed method can also be utilized for the determination of nitrate (NO^? ₃) after its reduction to nitrite. The method has been applied for the determination of various samples containing traces of nitrite.     

Indirect Determination of Bromhexine by Atomic Absorption Spectrophotometry

Abstract

A new procedure for determination of Bromohexine is described. The method consists of extracting an ion pair between the Bromhexine and the inorganic complex Co(SCN)² ₄ and measuring Co in the organic phase by AAS at 240. 7 nm. The optimal experimental conditions: pH, concentration of Co(SCN)² ₄, shaking time, phase ratio, number of extractions and the linear range of calibration are studied.

The organic phase used is 1,2-dichloroethane. The standard deviation of the method is 10^?3. The interference of foreign substances which accompany the Bromhexine in pharmaceutical preparations is studied, and the method is applied to their quantitative determination in medicines.     

Room Temperature Phosphorescence Optosensor for Terbium

Abstract

A solid surface room temperature phosphorescence optosensing method has been developed for the determination of terbium(III) based on the adsorption of its binary complex with 1,4-bis (l'-phenyl-3′-methyl-5′-pyrazolone-4′-) butanedione-(1,4) (BPMPBD) onto the hydrogen form of a strong cation exchange resin packed in a flow cell in an aqueous flow system. The phosphorescence intensity is a linear function of the concentration of terbium in the range of 8x10^?9 M-6x10^?7 M, and the detection limit is 3x10^?9 M terbium. The response mechanism was also studied. The present optosensor has been used for the determination of trace amounts of terbium in synthetic samples with satisfactory results.     

Chemiluminescence Flow Injection Determination of Copper (II)

ABSTRACT

A sensitive and selective flow injection chemiluminescence method for the determination of copper over the range of 0.5-7.5 ng is described. The method is based on quenching effect of copper (II) on the chemiluminescent reaction of dichlorofluorescein and hydrogen peroxide in alkaline media. Method development includes optimization of reagent concentrations and flow conditions. The optimized method yielded a detection limit (3σ) of 0.2 ng. The method is simple, fast, selective and precise and was used for the determination of copper in blood sera.