Rapid analysis of compounds responsible for ‘boar-taint’ using dynamic headspace with TD–GC–TOF MS
A group of researchers at the University of Bonn, Germany, have used a novel combination of Markes’ products to speed up and simplify the reliable quantitation of malodorous compounds in pig meat.
The research, led by Peter Boeker at the Institute for Agricultural Engineering, reports a quicker and more convenient alternative to current labour-intensive techniques for sample preparation and analysis of ‘fatback’ from male pigs. This fatty tissue can be contaminated with skatole, indole and androstenone – naturally-occurring lipophilic compounds that cause consumer complaints because of their offensive smell.
The system developed by Boeker’s team used a combination of dynamic headspace (HS), thermal desorption (TD), gas chromatography (GC) and time-of-flight mass spectrometry (TOF MS) to extract and analyse the volatile constituents of pig fatback. Rather than use solvent extraction or other laborious sample preparation techniques, the authors simply melted the fat in a microwave, transferred the liquid fat into a headspace vial, and spiked it with internal standards. This convenient sample handling, says Boeker, makes the new method “highly valuable for routine analysis, especially when investigating large sample sets”.
The headspace sampling used Markes’ HS5-TD™, modified with a dual needle assembly that allowed both continuous, dynamic trapping for more rigorous extraction and on-line purging with nitrogen to prevent oxidation. Samples were collected onto TD tubes, which were analysed with Markes’ ULTRA™–UNITY™ automated thermal desorption system, in conjunction with a Thermo TRACE Ultra GC and Markes’ BenchTOF™ mass spectrometer.
The authors found that the analytical system delivered “high accuracy and precision” with wide linearity, and limits of detection and quantitation for skatole, indole and androstenone well below the levels set for consumer acceptance. Analysis was enhanced by the use of Markes’ dynamic baseline compensation algorithm, which removes ions associated with background contamination such as column bleed. Here, this proved especially useful for the identification and quantitation of androstenone, which was strongly retained on the column and eluted in a region of high column bleed.
The work was also interesting because spiking the sample with deuterated versions of the target analytes allowed measurement of their gas-phase concentrations and their total concentration in the fatback sample. The authors suggest that this will allow them to understand how analyte concentrations in the fatback interact with the biological matrix to affect the perceived odour.
With the performance of the automated analytical system for this application now proven, the authors say the next step is to focus on making the analysis even faster, enabling its use as a routine rapid screen for boar taint at the point of slaughter. They suggest this might be done using methods such as fast GC, to which the BenchTOF is ideally suited because of its fast acquisition speeds.
If you’d like to find out more about this research, visit the journal’s website to download the full article, or contact one of our TOF specialists to discuss the application area in general.
Fast and solvent-free quantitation of boar taint odorants in pig fat by stable isotope dilution analysis–dynamic headspace-thermal desorption–gas chromatography/time-of-flight mass spectrometry
J. Fischer, T. Haas, J. Leppert, P.S. Lammers, G. Horner, M. Wüst and P. Boeker
Food Chemistry, 2014, 158: 345–350
For earlier work on boar taint done by Boeker in conjunction with Markes, see Application Note 511.