Deconvolution of gas chromatographic data

The use of deconvolution methods on gas chromatographic data to obtain an accurate determination of the relative amounts of each material present by mathematically separating the merged peaks is discussed. Data were obtained on a gas chromatograph with a flame ionization detector. Chromatograms of five xylenes with differing degrees of separation were generated by varying the column temperature at selected rates. The merged peaks were then successfully separated by deconvolution. The concept of function continuation in the frequency domain was introduced in striving to reach the theoretical limit of accuracy, but proved to be only partially successful

Analysis Of Persistent Organic Pollutants In Fish And Seafood: Health Risk Assessment Through Dietary Intake

Profil enam sebatian aroklor telah dibina menggunakan kromatografi gas-jisim spektrometer dan pemetaan puncak kongener bifenil politerklorin kepada masa penahanan masing-masing telah dilakukan dengan tahap keyakinan yang tinggi. The profiles of six aroclors were mapped out using gas chromatograph-mass spectrometer and the assignments of chlorinated biphenyl congeners peaks to their respective retention times were carried out with very good degree of certainty

Analysis Of Persistent Organic Pollutants In Fish And Seafood : Health Risk Assessment Through Dietary Intake [TD427.07.S981 2006 f rb] [Microfiche 8323].

Profil enam sebatian aroklor telah dibina menggunakan kromatografi gas-jisim spektrometer dan pemetaan puncak kongener bifenil politerklorin kepada masa penahanan masing-masing telah dilakukan dengan tahap keyakinan yang tinggi. The profiles of six aroclors were mapped out using gas chromatograph-mass spectrometer and the assignments of chlorinated biphenyl congeners peaks to their respective retention times were carried out with very good degree of certainty

Gas chromatographic determination of organochlorines in biota by preliminary fractionation on conditioned silica gel column

A complete method is described for the reliable determination in animal tissues of polychlorinated biphenyls (PCBs), aldrin, p,p -DDE, heptachlor, o,p -DDT, p,p -DDT, p,p -DDD, CI. -BHC, Y -BHC (lindane), heptachlor epoxide, dieldrin and endrin. It aims at over coming a plethora of difficulties, the gravest of which deal with analytes loss and alteration, interference, identification, fouling of the column and the detector of the gas chromatograph, non-linear response of the latter and contamination. It comprises hexane extraction, removal oflipids on an alumina column, separation into six fractions on a silica gel column and injection into a gas chromatograph equipped with a 6.3Ni electron capture detector. Special attention is paid to the conditioning of the silica gel column and the identification of all the peaks, including those of th e PCBs.peer-reviewe

Preliminary Study on Treatment of Contaminated Groundwater from the Taylorville Gasifier Site

Groundwater and soil at the site of an abandoned coal gasification plant in Taylorville, Illinois have been contaminated with compounds associated with coal conversion process waters. A preliminary study to assess the feasibility of using ethanol as a means of increasing the solubility of compounds adsorbed within the soil matrix followed by treatment of the ethanol/groundwater extract in an expanded-bed anaerobic granular activated carbon (GAC) reactor was conducted. Results of the study indicate that compounds in the groundwater are highly adsorb able on GAC, and do not interfere with the anaerobic degradation of ethanol in the reactor. Soil extractions with varying ethanol/water ratios were able to remove many additional low water solubility compounds from the soil.ENR Contract Number HWR87035published or submitted for publicationis peer reviewe

The use of high performance anion exchange chromatography for the detection of counterfeit pharmaceutical products using the excipient content as a marker

The aim of the investigation described here was to examine the differences between genuine and counterfeit pharmaceutical products through the development of an analytical method capable of rigorously identifying the sugar-based excipients. High Performance Anion Exchange Chromatography, coupled to Pulsed Amperometric Detection (HPAEC-PAD), supported by Gas Chromatography-Mass Spectrometry (GC-MS), provided a method for the analysis of the carbohydrate based excipients. The analytical method was able to discriminate between the substitution patterns of a number of monosaccharides derived from commonly used excipients and these were compared for both genuine and counterfeit sildenafil citrate based products. The aim of the project was accomplished: the HPAEC-method was employed to analyse a counterfeit pharmaceutical ‘Herbal Viagra’

Peak Alignment of Gas Chromatography-Mass Spectrometry Data with Deep Learning

We present ChromAlignNet, a deep learning model for alignment of peaks in Gas Chromatography-Mass Spectrometry (GC-MS) data. In GC-MS data, a compound's retention time (RT) may not stay fixed across multiple chromatograms. To use GC-MS data for biomarker discovery requires alignment of identical analyte's RT from different samples. Current methods of alignment are all based on a set of formal, mathematical rules. We present a solution to GC-MS alignment using deep learning neural networks, which are more adept at complex, fuzzy data sets. We tested our model on several GC-MS data sets of various complexities and analysed the alignment results quantitatively. We show the model has very good performance (AUC $\sim 1$ for simple data sets and AUC $\sim 0.85$ for very complex data sets). Further, our model easily outperforms existing algorithms on complex data sets. Compared with existing methods, ChromAlignNet is very easy to use as it requires no user input of reference chromatograms and parameters. This method can easily be adapted to other similar data such as those from liquid chromatography. The source code is written in Python and available online

Applications of high pressure differential scanning calorimetry to aviation fuel thermal stability research

High pressure differential scanning calorimetry (DSC) was studied as an alternate method for performing high temperature fuel thermal stability research. The DSC was used to measure the heat of reaction versus temperature of a fuel sample heated at a programmed rate in an oxygen pressurized cell. Pure hydrocarbons and model fuels were studied using typical DSC operating conditions of 600 psig of oxygen and a temperature range from ambient to 500 C. The DSC oxidation onset temperature was determined and was used to rate the fuels on thermal stability. Kinetic rate constants were determined for the global initial oxidation reaction. Fuel deposit formation is measured, and the high temperature volatility of some tetralin deposits is studied by thermogravimetric analysis. Gas chromatography and mass spectrometry are used to study the chemical composition of some DSC stressed fuels

Pyrolysis of brominated feedstock plastic in a fluidised bed reactor

Fire retarded high impact polystyrene has been pyrolysed using a fluidised bed reactor with a sand bed. The yield and composition of the products have been investigated in relation to fluidised bed temperature. The bromine distribution between the products and a detailed analysis of the oils using GC-FID/ECD, GC-MS, FT-ir, and size exclusion chromatography has been carried out. It was found that the majority of the bromine transfers to the pyrolysis oil and the antimony was detected in both the oil and the char. Oil made up over 89.9% of the pyrolysis products. Over 30% of the oil consisted of benzene, toluene, ethylbenzene, styrene and cumene. The pyrolysis gases were mainly hydrocarbons in the C1-C4 range but some HBr and Br2 was detected