Chemical analysis and NIR spectroscopy in the determination of the origin, variety and roast time of Mexican coffee.

Coffee is a product whose quality and price are associated with its geographical, genetic and processing origin; therefore, the development of analytical techniques to authenticate the above mentioned is important to avoid adulteration. The objective of this study was to compare conventional analytical methods with NIR technology for the authentication of roasted and ground coffee samples from different producing regions in Mexico (origins) and different varieties. A second objective was to determine, under the same processing conditions, if roasting times can be differentiated by using this technology.

Differentiation of types of crude oils in polluted soil samples by headspace-fast gas chromatography-mass spectrometry.

The coupling of a headspace sampler to a fast gas chromatography system with mass spectrometry detection is proposed as a method for the identification of the sources of contamination in soils due to the presence of hydrocarbons derived from petroleum. The samples are subjected to the headspace generation process, with no prior treatment, and the volatiles generated are separated by fast gas chromatography. The total time of the chromatogram per sample is less than six minutes.

Detection of soil pollution by hydrocarbons using headspace-mass spectrometry and identification of compounds by headspace-fast gas chromatography-mass spectrometry.

The direct coupling of a headspace sampler with a mass spectrometer is proposed as a screening tool for the rapid detection of soil pollution by hydrocarbons from petroleum and derivatives. The samples are subjected to the headspace generation process, with no prior treatment, and the volatiles generated are introduced directly into the mass spectrometer, thereby obtaining a fingerprint of the sample analysed. Suitable treatment of the signal by chemometric techniques allows unequivocal characterisation of the different types of sample.

A method for the detection of hydrocarbon pollution in soils by headspace mass spectrometry and pattern recognition techniques.

In the present work, we report a methodology for the rapid detection of soil pollution by hydrocarbons that is based on direct coupling of a headspace sampler with a mass spectrometer. With no prior treatment, the samples are subjected to the headspace generation process and the volatiles generated are introduced directly into the mass spectrometer, thereby obtaining a fingerprint of the sample analyzed. The mass spectrum corresponding to the mass/charge ratios (m/z) ranging between 49 and 160 atomic mass units (amu) contains the information related to the composition of the headspace and is used as the analytical signal for the characterization of the samples.