A new NMF algorithm has been proposed for the deconvolution of overlapping chromatograms of chemical mixture. Most of the NMF algorithms used so far for chromatogram separation do not converge to a stable limit point. To get same results for all the runs, instead of random initialization, three different initialization methods have been used namely, ALS-NMF (robust initialization), NNDSVD based...

Solubilities of some polycyclic aromatic hydrocarbons (PAHs) in supercritical carbon dioxide were measured with a procedure based on a direct on-line combination of a saturation cell to a flame ionization detector. Acenaphthene, anthrance and chrysene were selected as the test solutes. A method was developed and evaluated which enables the measurement of the contribution of solute vapor pressur...

The gas chromatographic conditions for the assay of vitamins D were described. The analysis was performed on Shimazu Gas Chromatograph GC 4AP equipped with a hydrogen flame ionization detector. Glass columns (4 i.d.•~ 1000mm) packed with 1.5% OV-17 on Shimalite W, 80-100 mesh, silanized, were operated at 240•‹ and a flow rate of 40ml/min (N2) was maintained. Adoption of "unmodified" D as an ana...

Cerebrospinal fluid (CSF) from uninfected patients and from patients with bacterial and viral meningitis was analyzed by gas-liquid chromatography, with use of a flame ionization detector, and by gas chromatography-mass spectrometry. The resulting profiles were consistent and reproducible. Hydroxy acids were the compounds found in greatest abundance in both normal and infected CSF. Control expe...

We investigated whether methane, ethylene and ethane gas can be detected in gas emanating from human skin, which is called skin gas. Skin gas was collected with a homemade stainless-steel trap system, which was cooled with liquid nitrogen, and analyzed with a gas chromatograph fitted with a flame ionization detector (FID). Skin-gas samples were obtained by covering a hand for 30 min with a poly...

In this study, the concentration levels of the probable carcinogenic PAH fractions, benzo[a]pyrene (BaP) and benzo[k]fluoranthrene (BkF) in fillets of some processed fish species were investigated. Fish species comprising Merluccius poli (hake), Tyrsites atun (snoek), Seriola lalandi (yellow-tail) and Brama brama (angel fish) were bought in fish shops at Gordon's Bay, Western Cape, South Africa...

Exhaust particulate from compression ignition (CI) engines running on engine and chassis dynamometers was studied. Particulate dichloromethane extracts were qualitatively and quantitatively analyzed for polycyclic aromatic hydrocarbons (PAHs) and biomarkers by gas chromatography with flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). PAH group profiles were mad...

A preparative gas chromatography (pGC) method was developed for the separation of isomers (cis- and trans-asarone) from essential oil of Acorus tatarinowii. The oil was primarily fractionated by silica gel chromatography using different ratios of petroleum ether and ethyl acetate as gradient elution solvents. And then the fraction that contains mixture of the isomers was further separated by pG...

Two retention time locked methods for the analysis of essential oil compounds are described. The first method is a gas chromatography/flame ionization detector method using a 50 m × 320 μm id × 1.05 μm HP-5 column. The second method is a gas chromatography/mass spectrometry method using a 30 m × 250 μm id × 0.25 μm HP-5MS column. Retention times of approximately 400 essential compounds were mea...

*Corresponding author, Email: [email protected] Tel./Fax: +234 8038 916768 ABSTRACT: Total concentrations of Cd, Cr, Co, Fe, Pb, Ni, Mn and Zn were determined by atomic absorption spectrophotometry in the surface sediments of Taylor Creek, Southern Nigeria. The most concentrated trace metals, ranging from 113.2 to 5160.7 mg/g-dry weights were Fe, Pb, Mn, Ni and Zn. There was no significant ...