Gas Chromatographic Quantitative Analysis of Methanol in Wine: Operative Conditions, Optimization and Calibration Model Choice

Abstract

The influence of the wine distillation process on methanol content has been determined by quantitative analysis using gas chromatographic flame ionization (GC-FID) detection. A comparative study between direct injection of diluted wine and injection of distilled wine was performed. The distillation process does not affect methanol quantification in wines in proportions higher than 10%. While quantification performed on distilled samples gives more reliable results, a screening method for wine injection after a 1:5 water dilution could be employed. The proposed technique was found to be a compromise between the time consuming distillation process and direct wine injection. In the studied calibration range, the stability of the volatile compounds in the reference solution is concentration-dependent. The stability is higher in the less concentrated reference solution. To shorten the operation time, a stronger temperature ramp and carrier flow rate was employed. With these conditions, helium consumption and column thermal stress were increased. However, detection limits, calibration limits, and analytical method performances are not affected substantially by changing from normal to forced GC conditions. Statistical data evaluation were made using both ordinary (OLS) and bivariate least squares (BLS) calibration models. Further confirmation was obtained that limit of detection (LOD) values, calculated according to the 3σ approach, are lower than the respective Hubaux-Vos (H-V) calculation method. H-V LOD depends upon background noise, calibration parameters and the number of reference standard solutions employed in producing the calibration curve. These remarks are confirmed by both calibration models used.

Processing Method for the Quantification of Methanol and Ethanol from Bioreactor Samples Using Gas Chromatography–Flame Ionization Detection

“…Several techniques have been recommended in the literature to quantify methanol in complex sample matrices. Some of these are (i) derivatization of sample matrices such as water–ethanol, 18 aqueous, 19 and alcohol; 20 (ii) direct injection of samples such as plasma, 21 whole blood, 22 alcohol, food products, 23 and wine; 24 (iii) HSA of wine, 25 washing filtrate, 26 and air; 16 (iv) solid-phase extraction of air; 27 and (v) dilution of cell cultures. 28 One of the most important and widely used techniques for the separation of a volatile component from biological samples is extraction.…”

A Reusable Eu3+ Complex for Naked‐Eye Discrimination of Methanol from Ethanol with a Ratiometric Fluorimetric Equilibrium in Methanol/Ethanol Mixtures

“…Methanol quantification is typically based on the use of advanced techniques such as head space gas chromatography (GC), [7][8][9][10] GC-flame ionization [11] detection, high-performance liquid chromatography (HPLC), Raman [12,13] and infra-red spectroscopy. ethanol) without performing chemical analyses.…”

“…ethanol) without performing chemical analyses. Methanol quantification is typically based on the use of advanced techniques such as head space gas chromatography (GC), [7][8][9][10] GC-flame ionization [11] detection, high-performance liquid chromatography (HPLC), Raman [12,13] and infra-red spectroscopy. [14] A bioenzymatic analytical system was developed consisting of two biosensors, one based on alcohol dehydrogenase (ADH) that responds only to the ethanol and the second one based on alcohol oxidase (AOX) that responds to both methanol and ethanol.…”