Preparation of Hair and Nail Samples for Trace Element Analysis

Abstract

The method of washing of human hair and nail samples is examined by neutron activation and γ-ray analysis. The amounts of Na, K, Br, Au, Zn and La that are removed by successive washings determine the optimum number of washing for removing these trace elements as surface contaminants. A total solution contact time with the nails is 5 minutes, and leaching effects are observed after 6 washings.     

High Performance Liquid Chromatographic Determination of Pirenzepine Dihydrochloride in Its Pharmaceutical Formulation

Abstract

A high-performance liquid chromatographic procedure for the determination of pirenzepine dihydrochloride as a bulk material and in its tablet dosage form (Gastrozepin^R) is presented. Normal phase liquid chromatography has been performed on a Micro-pack Si-10 column using ammonium hydroxide (28–30% NH₃) in methanol (0.75: 99.25% v/v) as mobile phase at a flow rate of 2 ml/min. Clobazam has been used as internal standard with retention times of 1.9 and 2.8 minutes for clobazam and pirenzepine dihydrochloride, respectively at 254 nm. Analytical calibration yields a linear relationship between 5 and 25 μg/ml, with correlation coefficient of 0.999. Tablets each labelled to contain 25 mg pirenzepine dihydrochloride give mean percentage found of 99.98 ± 0.4. A plot of logarithm of concentration against time for a solution in 6 N hydrochloric acid gives a straight line with a slope of - 0.197 day^?1. The proposed method is, therefore, a stability indicating method.     

Simultaneous determination of atropine,scopolamine, and anisodamine in Flos daturae by capillary electrophoresis using a capillary coated by graphene oxide

A novel CE method was developed for the separation and determination of three main tropane alkaloids in Flos daturae with a capillary coated by graphene oxide (GO). The GO‐coated capillary was characterized by SEM, energy dispersive X‐ray spectroscopy, and Raman spectroscopy, and the results indicated that the inner surface of the capillary was partially coated by GO. A phosphate solution (40 mM, pH7.0) containing 20% v/v methanol and 30% v/v acetonitrile was used as the running buffer for the analysis of the atropine, scopolamine, and anisodamine. The linear ranges of atropine, scopolamine, and anisodamine was 0.5–200 μg/mL with satisfactory correlation coefficients (R²) > 0.9987, and this novel method provided an efficient separation for three tropane alkaloids as well as a good reproducibility and stability. Finally, the method was successfully applied for the determination of these three tropane alkaloids in plant extracts.     

A New High Performance Chromatographic Method for Polyamine Analysis in Picea Needles,Without Previous Extract Purification

Abstract

A fully automated, fast and sensitive method for the separation of 19 interrelated amino compounds is presented.

With the help of a high performance amino-acid analyser, ion-exchange chromatography was used to separate ornithine, lysine and arginine from its decarboxylated products: putrescine, cadaverine and agmatine. Also included are ammonia, ethanolamine, histamine, aminopropane, diaminopropane, acetyl and carbamyl putrescine as well as most of the known polyamines, i.e.: nor-spermidine, spermidine, homospermidine, thermine, spermine and 1,7-diaminoheptane which serves as internal standard for the quantification. The method uses 2 buffers, 1 single temperature and fluorimetric detection. It takes 72 minutes and is of picomole sensitive level. This method is well suited for the analysis of crude samples without preliminary purification, thus saving time and reducing preparative losses.

The reproducibility of the method and its application for the analyses of samples from different biological sources, such as microorganisms, plant and animal material has been tested in our laboratory for more than one year with excellent results. This method could serve as a powerful tool for the analysis of these amino compounds in which there is currently considerable interest.

Preliminary results concerning compared studies of healthy and injured needles of air polluted Picea are discussed.     

Use of Inverse Multiple Linear Regression (ILS) for the Analytical Control of Pharmaceutical Preparations. UV-Visible Spectrophotometric Quantitation of an Active Principal in the Presence of Absorbing Excipients

ABSTRACT

The simplicity and robustness of inverse multiple linear regression (ILS) as a method for the analytical control of pharmaceutical preparations by UV–vis spectrophotometry is demonstrated. This calibration technique establishes a linear relation between the analyte concentration as dependent variable and absorbance values measured at a small number of wavelengths as independent variables. In this work, ILS was used to quantify the active principal in a pharmaceutical preparation commercially available as aqueous solution.

The preparation was diluted in 40:60 v/v methanol/aqueous 0.1 N NaOH and its UV spectrum recorded over the wavelength range 240–330 nm. The calibration equation was derived from laboratory-made solutions of the analyte and absorbing excipients in the preparation. The operating wavelengths used were those of the absorption maxima for the compounds of interest; the results are compared with those obtained by stepwise wavelength selection and high performance liquid chromatography (HPLC).     

Determination of Benzodiazepines in Serum by High Performance Liquid Chromatography Using Radially Compressed Columns and an Aqueous Methanolic Mobile Phase

Abstract

Diazepam, oxazepam and N-desmethyldiazepam are determined by high performance liquid chromatography using a radially compressed C18 column and an aqueous methanolic mobile phase. The chromatographic separation is completed within 10 minutes. The drugs are recovered from serum by extraction with hexane:ethyl acetate 70:30, v/v.

The method is linear in the range 50-1600 ng/ml for all the drugs, Coefficients of variation are less than 6.2% for two studied concentration levels.     

Extraction and simultaneous determination of metoprolol and α-hydroxy metoprolol in latent fingerprints by liquid chromatography tandem mass spectrometry

Abstract

A simple extraction and sensitive simultaneous analysis method for metoprolol and its metabolite alpha-hydroxy metoprolol in latent fingerprint using liquid chromatography-mass spectrometry was developed. The extraction procedure was optimized as scrubbing using cotton swabs for 30 times followed by ultrasonic assistance in 30?°C methanol for 5?min with power of 2000 W. Drug analysis was performed using the mixture of methanol and 0.1% formic acid solution (pH 3.5, 30:70, v/v) as the mobile phase under positive electrospray ionization condition. The linear range obtained was 1.0–500.0?ng/mL for MET, and α-MET, and the limit of detection and the limit of quantification were 0.3?ng/cotton swab and 1.0?ng/cotton swab, respectively. The method showed very slight matrix effect and good recovery to the analytes in the fingermarks. Evaluation of extraction substrates and developing methods showed that the method developed is best used for impermeable substrates and that the commercially development powders have very slight influence on the qualitative detection of metoprolol in fingermarks. Finally, the drug users distinguishing test proved that the method developed for pharmaceuticals could be applied in the forensic analysis for circling out the pool of suspects in the criminal investigation based on their drug use history.     

Determination of Total Sulphur in Vegetation by a Turbidimetric Method Following An Oxygen-Flask Combustion

Abstract

A rapid method of determining total sulphur in vegetation is described. The plant material is combusted in an oxygen-flask, and the sulphate content of an aliquot of the absorbing solution is determined turbidimetrically as barium sulphate. The method is convenient and accurate. Its results agree closely with those obtained by the AOAC magnesium nitrate procedure.     

Determination of Selected Quinolones and Fluoroquinolones by Use of TLC

Abstract

There are many different methods of quinolones determination. The most often used method of quinolones analysis is liquid chromatography. In this work some selected quinolones (cinoxacin, pipemidic acid) and fluoroquinolones (ofloxacin, pefloxacin) were separated with thin-layer chromatography (TLC). The two different mobile phases were used as follows: buffer solution (pH = 5.5)-methanol, 40:10 (v/v) and acetonitrile-water-acetic acid, 6:40:4 (v/v/v), respectively, for quinolones and fluoroquinolones. The following chromatographic parameters were calculated for these separations: R_F, ?R_F, R_M, and R_S. The possibility of qualitative determination of cinoxacin, pipemidic acid, ofloxacin, and pefloxacin using TLC was shown.     

Turbidimetric Determination of Ammonia Using 12-Molybdophosphoric Acid

Abstract

A turbidimetric method for the determination of ammonia was developed based on the co-precipitation of ammonium 12-molybdophosphate with thallium(I) 12-molybdophosphate. The analysis is carried out in strongly acidic solution which eliminates possible loss due to volatility and other interferences. Samples containing 0.1 to 3.0 mg of ammonia are conveniently analyzed in 30 minutes with a relative standard deviation 1.7%. A study of the effect of various diverse ions was conducted.     

Simultaneous Determination of Nickel and cobalt in Manganese Sulphate Electrolyte by DMGH2-Sensitized Differential Pulse Polarography

Abstract

A method is described for the simultaneous determination of nickel and cobalt in manganese sulphate electrolyte by the dimethylglyoxime (DMGH₂) sensitized differential pulse polarography. The high manganese sulphate background (1.2M) in the concentrated process plant electrolyte interferes only with the nickel determination and precludes its direct determination. A 50% v/v dilution and an excessive amount (2 × 10^?3M) of the chelating agent are required at pH7.7 for the reliable determination of both elements. Under these conditions, the linear concentration ranges are 0-110 μg/1 for nickel and 0-140 μg/1 for cobalt. The minimum detectable amounts above the levels present in the process plant electrolyte are 2 μg/1 and 1 μg/1 for both elements, respectively. The relative standard deviations for all measurements are between 1 and 3%.     

An Ion Exchange Separation-Atomic Absorption Spectrophotometric Method for the Determination of Microgram Quantities of Copper,Iron and Zinc in Infant Milk Formula: Powder Form.

Abstract

An atomic absorption spectrophotometric method is described for the determination of microgram quantities of copper, iron and zinc in infant formula powdered milks. After sample digestion in concentrated nitric acid in a pressure vessel, the solution is evaporated till dryness, and then a solution of 6M HCl is added, in order to form the chlorocomplexes of the metals. This acid solution is passed through an ion-exchange column (anion exchange resin, chloride form). The metals are eluted from the column with diluted acid mixture of 0.005M HCl + 0.5% (v/v) HNO₃, and then the eluate is evaporated till dryness. The residue is dissolved in 1% (v/v) HNO₃, and then atomized into an air-acetylene flame. A standard addition procedure was employed as a back-up technique. The results obtained by this proposed method and those obtained by the standard addition technique were statistically treated, compared and discussed in this paper.     

A Simple Digestion Procedure for the Determination of Cadmium,Copper, Molybdenium and Vanadium in Plants by Graphite Furnace Atomic Absorption Spectrometry and Mass Inductively Coupled Plasma Spectrometry.

Abstract

A simple digestion procedure for the determination of Cd, Cu, Mo and V in plant leaves by graphite furnace atomic absorption spectrometry and mass inductively coupled plasma was developed. Approximately to 100 mg of the previously dried plant material (200 mg of fresh material) were weighed into a 50mL plastic conical ended vial and 2mL of subboiled 65% HNO₃ was added. The vial was then tightly closed and digestion performed at 80°C in an oven overnight; thereafter, 2mL of 30% H₂O₂ were added and a light yellow solution was obtained. The volume was made up to 50mL in the vial itself and the solution was ready for analysis. Although the time required for the digestion is long, large batches are possible, and make the procedure useful for high sample throughput. As only one vessel is used for the whole procedure, contamination risks are minimized. The reagents employed are possible to be obtained with high purity, permitting low blank values and detection limits. The accuracy of the procedure was tested by the analysis of certified reference materials and good concordance was observed between experimental and certified values.     

Evaluation of a New Method for the Determination of Elements in Vegetable Foods and Feeds by Atomic Absorption Spectroscopy with Sampling of Carbonaceous Slurry

Abstract

The new method, proposed in a preceeding paper for the determination of elements in plant material by flame atomic absorption spectroscopy (FAAS) with liquid sampling of carbonaceous slurry, was tested on other kinds of organic material such as vegetable foods and feeds. Results are reported for the determination of calcium, magnesium, potassium, iron, manganese, zinc and copper in these materials. Also, the analytical results relative to the determination of cadmium by graphite-tube furnace atomic absorption spectroscopy (GTFAAS) for two matrices are given. In all cases accuracy and precision of the analytical procedure were ascertained.     

Simultaneous Analysis Of Estradiol Dienanthate,Estradiol 3-Benzoate And Testosterone Enanthate Benzilic Acid Hydrazone In Oily Formulations Bygradient-Hplc

Abstract

A procedure is described for the analysis of estradiol-3-benzoate, testosterone enanthate benzylic acid hydrazone and estradiol dienanthate in oily solution. The multi-step gradient reversed phase ion-pairing HPLC method uses 1-pentane sulfonic acid sodium salt (0.0025 M in 0.1% acetic acid methanolic solution): acetonitrile and water (55 : 30 to 45 : 15 to 0) mobile phase gradient and a 250 × 4.6 mm, 5 micron octadecyl silane column, with 1,2,4,5-tetrachlorobenzene as internal standard. The time required for chromatography is 31 minutes. The method gives relative standard deviations (RSD) of .94% or better for the assay of active ingredients in commercial formulations.     

Determination of Phenols and Cresols in Urine by Gas Chromatography

Abstract

A rapid, simple, and sensitive method was developed for the determination of three cresol isomers and phenol in urine. The sample was spiked with m-chlorophenol, as internal standard, and hydrolyzed with sulfuric acid at ambient temperature. The hydrolyzed solution was saturated with ammonium sulfate and extracted with ethyl acetate. The extract was injected without derivatization into a gas chromatograph fitted with a flame ionization detector and a glass column packed with 0.1% SP 1000 on Carbopack C. All four analytes, which eluted within 13 minutes, were quantified from standard curves.

The method was evaluated by analysis of spiked urine pools from laboratory workers and samples of urine from workers in a coal gasification plant.     

Determination of lanthanum and rare earth elements in bovine whole blood reference material by ICP-MS after coprecipitation preconcentration with heme-iron as coprecipitant

An analytical method for the determination of lanthanide elements in the bovine whole blood reference material (IAEA A-13) has been investigated by inductively coupled plasma mass spectrometry (ICP-MS). The bovine whole blood reference material was digested with HNO₃ and HClO₄, and then the pH of the digested solution was adjusted to 12 with 3 M sodium hydroxide aqueous solution. In this experimental procedure, lanthanide elements in the blood sample were coprecipitated with iron mainly derived from heme-iron in blood itself. In order to minimize matrix effects due to iron, excess iron in the analysis solution was removed by solvent extraction using methyl isobutyl ketone (MIBK) prior to the determination of lanthanide elements by ICP-MS. The recoveries of all lanthanide elements were almost quantitative in the recovery test. In consequence, it has been found that all lanthanide elements in bovine whole blood reference material are at the wide concentration range of 0.90 pg/g for Tm ∼1880 pg/g for Ce. Received: 2 May 1998 / Revised: 27 July 1998 / Accepted: 30 July 1998     

Determination of lanthanum and rare earth elements in bovine whole blood reference material by ICP-MS after coprecipitation preconcentration with heme-iron as coprecipitant

An analytical method for the determination of lanthanide elements in the bovine whole blood reference material (IAEA A-13) has been investigated by inductively coupled plasma mass spectrometry (ICP-MS). The bovine whole blood reference material was digested with HNO₃ and HClO₄, and then the pH of the digested solution was adjusted to 12 with 3 M sodium hydroxide aqueous solution. In this experimental procedure, lanthanide elements in the blood sample were coprecipitated with iron mainly derived from heme-iron in blood itself. In order to minimize matrix effects due to iron, excess iron in the analysis solution was removed by solvent extraction using methyl isobutyl ketone (MIBK) prior to the determination of lanthanide elements by ICP-MS. The recoveries of all lanthanide elements were almost quantitative in the recovery test. In consequence, it has been found that all lanthanide elements in bovine whole blood reference material are at the wide concentration range of 0.90 pg/g for Tm ∼1880 pg/g for Ce. Received: 2 May 1998 / Revised: 27 July 1998 / Accepted: 30 July 1998     

HPLC Analysis of Estrone Released from Polylactic Acid Microspheres

Abstract

A simple and rapid HPLC method was developed to quantitate the in vitro release of estrone from poly(l-lactic acid) microspheres. Propylparaben was used as the internal standard. The method employed a reversed-phase column (LiChrosorb 5μm, RP-18, 125 × 4 mm I.D.). The isocratic mobile phase system was a 60:40 (v/v) mixture of methanol and aqueous acetate buffer (pH 5.4). Standard curves were linear over the desired range at both 214 nm and 280 nm. Because of the greater sensitivity at 214 nm this wavelength was chosen for further analyses. A flow rate of 1.8 ml/min yielded a retention time of 3.5 minutes for estrone and 2.0 minutes for the internal standard and the method was found to be reproducible (RSD of less than 3%). The molar absorpuvities for estrone in different solvents and the mobile phase are presented.     

An improved method of simultaneous determination of lutein and zeaxanthin in food

Based on an official standard method of lutein analysis, an improved high performance liquid chromatography (HPLC) method for simultaneously detecting lutein and zeaxanthin was developed as focusing on the sample preparation protocol. The optimal pretreatment conditions included a saponification in a water bath for 15?min at a constant temperature of 50?°C, using a 10?mL 60% (w/v) potassium hydroxide solution, followed by extraction using 100?mL mixture of n-hexane, ethyl ether and cyclohexane (40: 40: 20, v/v/v). A mixture of dichloromethane, acetonitrile and methanol (20: 30: 50, v/v/v) was validated to elute lutein and zeaxanthin on a C₃₀ column (4.6?×?250?mm, 5?µm). The resolution between lutein and zeaxanthin is ≥2.5. A millet sample was used for methodological verification and the results showed that the linear relations for lutein and zeaxanthin were good in ranges of 0.23–9.37?μg/mL and 0.30–12.02?μg/mL, respectively. The relative standard deviations of lutein and zeaxanthin were 1.40% and 5.09%, respectively, and their spiked recoveries were between 86.60% and 98.75%. The lutein and zeaxanthin results from this modified HPLC method are superior to those from the Chinese official method and ultrasonic extraction method.