Quantitative measurements of inorganic mercury and organomercurials in water and biological media by gas-liquid chromatography

Gas-liquid chromatography is used to determine inorganic mercury in the presence and absence of organomercurials in water and biological media after alkylation or arylation. Best results for inorganic mercury were realized with pentacyanomethylcobaltate(III) and tetraphenylborate(III), via the generated methyl and phenyl mercurial. Tetraethyltin, forming ethylmercury, was less satisfactory. Lower detection limits with these reagents were in the range 10–30 ng Hg ml^-1 of medium. Co-determination of inorganic mercury and various organomercurials was carried out by sequential or simultaneous procedures with several column temperatures and packings. Optimal Chromatographic results were achieved with Durapak Carbowax 400 (low K') on Porasil F and 10% DEGS on Anakrom SD.     

Rapid determination of selenium in various substrates by electron capture gas-liquid chromatography.

In the proposed procedure for the determination of selenium, 0.5-1 g of sample is wet ashed with concentrated nitric acid. After adding 1,2-diamino-4,5-dichlorobenzene to the digest at pH 1, the resulting dichloropiazselenol derivatives is extracted with toluene. The extract is purified by column chromatography over Florisil and analyzed by gas-liquid chromatography with electron capture detection. Recoveries of selenium added to various substrates ranged from 72 to 102%. The limit of detection is approximately 0.01 ppm, but smaller amounts can be determined by increasing the sample size or by concentration of the final extract.     

Quantitative measurements of inorganic and methyl arsenicals by gas-liquid chromatography

Procedures are described for determinations of inorganic and methylated arsenicals in urine and water by gas—liquid chromatography of the corresponding diethyldithiocarbamate complexes. Silanized 5 % OV-17 on Anakrom AS as packing is used in an instrument equipped with electron-capture detection (³H foil). Samples of water or urine are treated to generate the iodides of inorganic, mono- and dimethylarsenic and these are treated with diethyldithiocarbamate, followed by isolation into various organic solvents. Recovery and precision s_r data for the analysis of the arsenicals in urine include: inorganic (1.0 p.p.m.), 82.6%, ± 7.7; monomethylarsenic (0.5 p.p.m.), 91.5 %, ± 7.0; dimethylarsenic (0.5 p.p.m.), quantitative, ± 4.0.

     

Advances in the determination of inorganic anions by ion chromatography

The time period covered for this review includes articles published from 1997 to 1999, with the addition of a few classic references. The purpose of the review is to include the most relevant works from each topic area of the determination of inorganic anions by ion chromatography, including new sample pretreatments, new separation methods, new detection systems and the latest applications in the field of environmental, water, foods, etc. samples. Experimental conditions such as stationary phase, eluent, detection mode, as well as matrix are summarized in a table.     

The determination of phanquone in biological material by gas-liquid chromatography.

A gas-liquid chromatographic method for the quantitative determination of phanquone is described, based on the formation of a dimethoxine prior to its extraction from biological material. The sensitivity of the procedure is about 15 ng/ml in biological fluid.     

Photoelectrochemical determination of inorganic mercury in aqueous solutions

An analytical method using an optical probe in a photoelectrochemical cell for the sensitive and selective determination of aqueous Hg²⁺ is presented. A previously synthesized Hg²⁺ selective chemosensor, proven to be Hg²⁺ sensitive up to 2 μg L⁻¹, has been immobilized onto indium tin oxide (ITO) electrodes in a composite form with polyaniline. The coated ITO electrode was placed in a photoelectrochemical cell under closed circuit conditions in which the optical recognition of the chemosensor was converted to a measurable signal. A composite of the fluorescent chemosensor, Rhodamine 6G derivative (RS), and polyaniline (PANI) was immobilized on ITO glass plates and subjected to photovoltage measurements in the absence and presence of Hg²⁺. The optical responses of the coated electrode were used to determine the sensitivity and selectivity of the immobilized sensor to Hg²⁺ in the presence of background ions. The optical response of the PANI-dye coated electrode increased linearly with increasing Hg²⁺ concentration in the range 10-150 μg L⁻¹, with a detection limit of 6 μg L⁻¹.     

Separation and quantitative determination of the cerium group lanthanides by gas-liquid chromatography

A gas chromatographic method is reported for the separation and subsequent quantitative determination of the cerium group lanthanides. The lanthanides (RE) are synergistically extracted from aqueous solution with the polyfluorinated beta-diketone 1,1,1,2,2,6,6,7,7,7-decafluoro-3,5-heptanedione, H(FHD), as ligand, and di-n-butylsulphoxide, DBSO, as neutral donor. The composition of the extracted species is reported to be RE(FHD)(3) .2DBSO. Thermogravimetric analysis of the complexes is reported. Analytical curves were prepared and found to be usable over the range of 0.1-10 mug of metal. Individual lanthanides were determined with 99.0 % recovery with a relative mean deviation of +/-2.0%. Mixture of lanthanides were analyzed with 101.2% recovery with a relative mean deviation of +/-2.2%.     

Simultaneous determination of some active ingredients in cough-cold syrups by gas-liquid chromatography

A simple, efficient and accurate gas-liquid chromatography (GLC) method for the simultaneous determination of eight active ingredients in cough-cold syrups has been developed. The active ingredients under study were bromhexine, chlorpheniramine, codeine, dextromethorphan, diphenhydramine, ephedrine/pseudoephedrine, guaiphenesin and papaverine. Before injection, the active ingredients were first separated, from the excipients present in the cough-cold syrups, with chloroform, from alkaline medium. They were then separated by GLC on a glass column (5 ft x 2 mm i.d.) packed with 3% of OV-25 supported on Supelcoport (80-100 mesh). The column temperature was maintained at 170 degrees C for 1 min, then programmed to 265 degrees C at a rate of 10 degrees C min-1, and maintained at this temperature for 10 and 1 min, respectively, for samples with and without papaverine. The flow-rate of the nitrogen carrier gas was 30 ml min-1. A flame-ionisation detector was used for detection, and clomipramine hydrochloride was used as the internal standard. The recoveries of the drugs ranged from 96.0 to 99.7%, and the relative standard deviations for ten replicate determinations ranged from 0.49 to 4.7%. Results are reported for nine commercially available cough-cold syrups.     

Simultaneous determination of oxygen and mercury in inorganic and organic mercury compounds

Oxygen and mercury in inorganic and organic mercury compounds are determined simultaneously by a modification of the Schütze-Unterzaucher method. The determination of mercury is not influenced by the presence of sulphur and nitrogen in the samples. In 13 inorganic and organic mercury compounds, oxygen has been determined with an error of less than 0.4% and mercury with an error of less than 0.5%.