HYPHENATION AND MULTIDIMENSIONALITY AS SAMPLE PREPARATION ALLEYS IN MOSH AND MOAH ANALYSIS

Multidimensional separation techniques are a powerful class of analytical techniques that allow
to increase the separation power of complex samples, most frequently in an automated and
hyphenated way. The most important parameter two optimize is the orthogonality of the
separation techniques in order to maximize the overall separation. Most usually two
chromatographic dimensions are coupled for this purposes (e.g., GC-GC or GC×GC, LC-GC or
LC×GC, LC-LC or LC×LC), with often the addition of mass spectrometry as an extra dimension.
Few samples really benefit for additional dimensions, and mineral oil, more specifically mineral
oil saturated and aromatic hydrocarbons (MOSH and MOAH) are one of this. The reference
method for this analysis is the LC-GC-FID method developed by Grob and Biedermann in 2009
[1]. In this method, the LC step is used as a preliminary sample preparation step to separate
MOSH and MOAH and the rest of the sample (mainly lipid components). Beside LC-GC,
comprehensive gas chromatography (GC×GC) has been proposed to better investigate the
identity of the MOSH and MOAH fraction.
In this work, we proposed a fully integrated platform, namely LC-GC×GC-ToFMS/FID, coupled
with a novel integration algorithm, to improve results reliability. Every dimension involved was
an important alley for sample preparation allowing an additional “chromatographic purification”
of the MOSH and MOAH hump from the interferences still remaining after the previous LC step
[2].