Spectroscopy Laboratory, The Dow Chemical Company, Midland, Michigan, USA In December 1955 or thereabouts, the authors coupled a homemade gas chromatograph to a research time-of-flight mass spectrometer constructed by W. C. Wiley, I. H. McLaren, and D. B. Harrington. This unique gas chromatography/mass spectrometry (GC/MS) instrument generated mass spectra at a lo-kHz rate for display on an osc...

We estimated the nutritive value, vitamin content, amino acid composition, fatty acid content, and mineral profile of a phytococktail comprising sea buckthorn (Hippophae rhamnoides), apricot (Prunus armeniaca), and roseroot (Rhodiola imbricata) from trans-Himalaya. The free vitamin forms in the phytococktail were determined by rapid resolution liquid chromatography/tandem mass spectrometry (RRL...

A gas chromatography-mass spectrometry method for quantification of polyhydroxyalkanoates (PHAs), containing 4-carbon to 16-carbon monomers, even in the absence of standards, was developed. Strong linear correlations existed between PHA carbon number and retention time/response factor (R(2) ≥ 0.987). Based on the correlations, high recovery values, between 100.5% and 114.3%, were obtained for P...

Pyrolysis of agricultural waste to produce fuel gas involves formation of tars as noxious by-products. In this paper the qualitative analysis of tars formed during pyrolysis of rice husks is presented, based on identification by gas chromatography-mass spectrometry and interpolation of retention times on a polyaromatic hydrocarbon index scale. The influence of some reaction parameters on produc...

The composition of sediment organic matter (OM) exerts a strong control on biogeochemical processes in lakes, such as those involved in the fate of carbon, nutrients and trace metals. While between-lake spatial variability of OM quality is increasingly investigated, we explored in this study how the molecular composition of sediment OM varies spatially within a single lake and related this vari...

background: a new microextraction method named dispersive liquid-liquid microextraction (dllme) for determination of chloroform in pool water and blood of swimmers after swimming is described. methods: this method was performed based on coupling dispersive liquid-liquid microextraction (dllme) with gas chromatog­raphy-mass spectrometry (gc-ms). methanol and trichloroethylenes were used as the d...

background adulterated herbal weight loss products with containing undeclared synthetic drugs are common and responsible for many serious health damages. objectives the purpose of the study was to determine five synthetic adulterants in eight common herbal weight loss supplements, which are currently sold in iran markets, to verify their presence in supplements, without mentioning on the labels...