We were able to analyze the pure oil and its chemical reaction products (which are not shown in this report) using the Aviv Analytical 5975-SMB GC-MS with Cold-EI, and in this post we present the Jojoba oil analysis results and conditions.
- The main goal of analyzing Jojoba oil was easily achieved, including all its heavy major compounds up to and including its minor triglycerides (as shown in figures 1 and 3 below). This is in contrast to standard GC-MS in which the Jojoba oil heavy esters either do not elute or that their elution can not be ensured.
- Clear and dominant or abundant molecular ions were observed for all the oil mixture compounds, which is in contrast to expectations for standard EI (figure 1 and 3).
- The Tal-Aviv Molecule Identifier (TAMI) software based on isotope abundance analysis helped in the identification of these large esters that are not included in the NIST library, via the provision of elemental formulas (as shown in figure 2 below).
- Reasonable chromatographic separation without any peak tailing was achieved with the 5975-SMB, despite the use of short column for extended range of heavy compounds.
- The analysis took only 17 min, which is over twice faster than with standard GC-MS analysis of heavy compounds.
- Excellent TIC sensitivity was obtained of >30,000 (peak to peak as shown in figure 3) for the most prominent peak thereby enabling the analysis of minor oil ingredients at the sub 0.1%. Excellent ratio of TIC peek heights to column bleed level was also achieved which further helped in the heavy oil components identification.
- The 5975-SMB uniquely exhibits uniform response to all the oil compounds thereby uniquely enabled quantitative analysis of the oil composition, unlike with standard GC-MS.
- We found that the Jojoba oil is primarily composed of 6-7 heavy esters, each with two double bonds, and they differ from each other by two carbon atoms (C2H4). The main ingredient being at ~50% of the oil is C42H80O2 (m/z= 616.7)
- The simplicity of the Jojoba oil mass chromatogram and availability of molecular ions in Cold EI uniquely enable the identification of the oil as a material even at low concentrations, for forensic or other applications.