A process for identifying an unknown compound in a sample includes matching a peak in a primary Fourier Transform Infrared spectral region of the sample spectrum with reference spectra in the same spectral region to generate an initial list of potential candidates, based, for example on goodness of fit criteria. The initial list can be reduced by retention time information and/or global peak matching techniques that analyze the sample spectrum in regions outside the primary region.

A portable apparatus to sample and analyze volatile organic compounds in breath air, includes: a box internally divided in two internal sections, each housing a sample collecting tube or filter in turn containing a stationary phase suitable for retaining determined analytes, as drugs and/or respective metabolites, having specific chemical physical properties, contained in breath air; a pre-accumulation chamber for receiving breath air from the outside through a breath entrance connection and for feeding the received breath air to the sample collecting filters housed in the two sections, with these two sample collecting filters being connected in parallel to the chamber; and a tool application kit for removing the two sample collecting filters from the respective sections in the box of the apparatus, in a way that avoids any contamination thereof, and for extracting the analytes that are retained by the stationary phase on the same two sample collecting filters.

The disclosed system and method concentrates and enriches a chemical sample while removing water and/or CO2 prior to analysis, improving detection limits and repeatability of quantitative chemical analysis without the need for cryogenic or sub-ambient cooling. The system can include a valve system, a dewpoint control zone, and a multi-capillary column trapping system (MCCTS). During a first time period, the valve system can couple the dewpoint control zone to the MCCTS. During a second time period, the valve system can couple the MCCTS to the chemical separation column such the dewpoint control zone is bypassed. Excess water included in the sample can condense in the dewpoint control zone as the sample transfers to the dewpoint control zone and MCCTS. When the sample is transferred from the MCCTS to the chemical separation column, the condensed water in the dewpoint control zone is not transferred to a chemical separation column.

Techniques are described for quantification of molecules in a sample. Mass spectrometry is performed to obtain ionization intensities for precursor and product ions originating from a particular molecule. A first stet of precursor ions having the highest ionization intensities and originating from the particular molecule is determined. For each of the one or precursors in the first set, determined is a second set of one or more product ions that are fragments associated with said each precursor and have the highest ionization in intensities of product ions associated with said each precursor. An intensity sum is calculated for the particular molecule by adding ionization intensities of product ions included in the second sets for the one or more precursors in the first set. The intensity sum is compared to information included in a calibration standard. A quantity of the particular molecule in the sample is determined based on said comparing.

Gas chromatograph-mass spectrometer comprising an ion source, the walls of which are realized or covered with at least one layer of graphene. Thus realized, the gas chromato graph-mass spectrometer proves to be particularly suited to the analysis samples containing hydrogen in addition to the substances to be analyzed. This situation generally occurs when the mass spectrometer is coupled to a gas chromatograph that utilizes hydrogen as the carrier gas.

Systems and methods for extracting hydrocarbon gas utilize a vacuum chamber with a mud chamber portion that is expandable and contractible. Gas is extracted at vacuum pressures.

A sample extraction device and a desorption device for use in gas chromatography (GC), gas chromatography-mass spectrometry (GCMS), liquid chromatography (LC), and/or liquid chromatography-mass spectrometry (LCMS) are disclosed. In some examples, the sample extraction device includes a lower chamber holding a sorbent. The sample extraction device can extract sample headspace gas from a sample vial by placing the sorbent inside the vial and creating a vacuum to increase recovery of low volatility compounds, for example. Once the sample has been collected, the sample extraction device can be inserted into a desorption device. The desorption device can control the flow of a carrier fluid (e.g., a liquid or a gas) through the sorbent containing the sample and into a pre-column and/or a primary column of a chemical analysis device for performing GC, GCMS, LC, LCMS, and/or some other chemical analysis process.

A gas chromatographic method for detecting a marker compound in a fuel by (a) introducing a sample of fuel into a first capillary column coated with a stationary phase based on polydimethylsiloxane and allowing the sample to flow through the first column to produce a first effluent; (b) allowing the first effluent to pass through a detector and identifying a retention time range in it which includes a retention time of the marker compound; (c) introducing only a portion of the first effluent stream which is within the retention time range into a second capillary column coated with either (i) an ionic sorbent or (ii) a polyethylene glycol, and allowing said portion to flow through the second capillary column to produce a second effluent stream; and (d) allowing the second effluent to pass through a detector; wherein the marker compound has formula Ar(R.sup.2).sub.m(OR.sup.1).sub.n and is present in the fuel at a level from 0.01 ppm to 100 ppm.

An automated dispersive liquid-liquid microextraction method of detecting and quanta N-nitrosamines in an aqueous sample. The method includes (a) extracting an aqueous solution containing the N-nitrosamines by mixing an extraction solvent and a dispersive solvent with the aqueous solution, such that the N-nitrosamines, or a portion thereof, re-distribute from the aqueous solution to the extraction solvent, (b) permitting the resulting mixture in (a) to form a two-phase mixture containing an aqueous phase comprising containing the aqueous solution with reduced amounts of the N-nitrosamines and an organic phase containing the extraction solvent with the N-nitrosamines extracted from the aqueous solution, (c) injecting the organic phase, or a portion thereof, into an injection port of a gas chromatograph coupled with at least one mass spectrometer, and (d) analyzing the N-nitrosamines by gas chromatography and mass spectrometry to detect and quantify the concentration of the N-nitrosamines in the aqueous solution.

Mass spectrometry for a specimen is repeatedly performed while stepwise changing a parameter (for example, a current value) of an emitter current. Based on a plurality of chromatograms generated by this process, an evaluation value table including a plurality of evaluation values is generated. An individual evaluation value shows a degree of tailing for individual peak included in each chromatogram. A parameter function is generated based on the evaluation value table. The parameter of the emitter current is controlled according to the parameter function.