Characterization and analysis of non-ionic surfactants by supercritical fluid chromatography combined with ion mobility spectrometry-mass spectrometry
Comprehensive separation and analysis of non-ionic surfactants have been conducted by coupling supercritical fluid chromatography (SFC) with ion mobility spectrometry-mass spectrometry (IMS-MS). Representative non-ionic surfactants were investigated, including alkylphenol ethoxylates (APEOs), e.g., octylphenol ethoxylates (OPEOs) and fatty alcohol ethoxylates (FAEs), e.g., lauryl alcohol ethoxylates (LAEs). A sub-2-μm high-density diol column was used for chromatographic separation by the first-dimensional SFC due to the differences in ethoxy chain prior to electrospray ionization (ESI). Maintaining the fidelity of pre-ionization separation in the first dimension, the introduction of IMS provided additional post-ionization resolution by broadly fractionating the oligometric ethoxymers based on their size and electric charge within 13.78 ms. Distinguishable series of singly and multiply charged non-ionic species could be clearly observed. The millisecond timescale ion mobility separation perfectly fits the elution time of a chromatographic peak, while effectively feeding components into the fast-scanning time-of-flight (TOF) mass analyzer for characterization and analysis. The orthogonality of the developed separation and analysis system was evaluated, revealing a correlation coefficient and peak spreading angle of 0.2729 and 74.16° for the studied OPEOs and 0.1962 and 78.69° for LAEs. Significant enhancement in peak capacity was achieved for the developed SFC-IMS-MS system with the actual peak capacity measured to be approximately 41 and 160 times higher than that of the dimensions of SFC and IMS, respectively, when used alone.
KeywordsSupercritical fluid chromatography Ion mobility spectrometry-mass spectrometry Non-ionic surfactants Alkylphenol ethoxylates Fatty alcohol ethoxylates
This work was financially supported by the National Key R&D Program of China (2016YFF0203702).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- 4.Gatidou G, Thomaidis NS, Stasinakis AS, Lekkas TD. Simultaneous determination of the endocrine disrupting compounds nonylphenol, nonylphenol ethoxylates, triclosan and bisphenol A in wastewater and sewage sludge by gas chromatography–mass spectrometry. J Chromatogr A. 2007;1138(1-2):32–41. https://doi.org/10.1016/j.chroma.2006.10.037.CrossRefGoogle Scholar
- 9.González S, Petrović M, Radetic M, Jovancic P, Ilic V, Barceló D. Characterization and quantitative analysis of surfactants in textile wastewater by liquid chromatography/quadrupole-time-of-flight mass spectrometry. Rapid Commun Mass Spectrom. 2008;22(10):1445–54. https://doi.org/10.1002/rcm.3527.CrossRefGoogle Scholar
- 10.Luo X, Zhang L, Niu Z, Ye X, Tang Z, Xia S. Liquid chromatography coupled to quadrupole-Orbitrap high resolution mass spectrometry based method for target analysis and suspect screening of non-ionic surfactants in textiles. J Chromatogr A. 2017;1530:80–9. https://doi.org/10.1016/j.chroma.2017.11.001.CrossRefGoogle Scholar
- 11.Berger TA. Supercritical fluid chromatography: overview. Reference module in chemistry, molecular sciences and chemical engineering. Elsevier; 2013.Google Scholar
- 15.Auerbach RH, Dost K, Jones DC, Davidson G. Supercritical fluid extraction and chromatography of non-ionic surfactants combined with FTIR, APCI-MS and FID detection. Analyst. 1999;124(10):1501–5. https://doi.org/10.1039/A905527D.
- 16.Pan J, Ji Y, Du Z, Zhang J. Rapid characterization of commercial polysorbate 80 by ultra-high performance supercritical fluid chromatography combined with quadrupole time-of-flight mass spectrometry. J Chromatogr A. 2016;1465:190–6. https://doi.org/10.1016/j.chroma.2016.08.051.CrossRefGoogle Scholar
- 17.Jiang Z-J, Cao X-L, Li H, Zhang C, Abd El-Aty AM, Jin F, Shao H, Jin M-J, Wang S-S, She Y-X, Wang J. Fast determination of alkylphenol ethoxylates in leafy vegetables using a modified quick, easy, cheap, effective, rugged, and safe method and ultra-high performance supercritical fluid chromatography–tandem mass spectrometry. J Chromatogr A. 2017;1525:161–72. https://doi.org/10.1016/j.chroma.2017.10.035.
- 18.Bijttebier S, D’Hondt E, Noten B, Hermans N, Apers S, Voorspoels S. Ultra high performance liquid chromatography versus high performance liquid chromatography: stationary phase selectivity for generic carotenoid screening. J Chromatogr A. 2014;1332:46–56. https://doi.org/10.1016/j.chroma.2014.01.042.CrossRefGoogle Scholar
- 19.Wilkins CL, Trimpin S. (Ed.). (2011). Ion mobility spectrometry-mass spectrometry. Boca Raton: CRC Press., 2013.Google Scholar
- 21.Ma Q, Xi G-C, Wang C, Bai H, Zhang Q, Xi H-W, Wang Z-M, Guo L-H. Comprehensive two-dimensional separation for the analysis of alkylphenol ethoxylates employing hydrophilic interaction chromatography coupled with ion mobility-mass spectrometry. Int J Mass Spectrom. 2012;315:31–9. https://doi.org/10.1016/j.ijms.2012.02.010.
- 22.Ma Q, Ma W, Chen X, Wang Z, Bai H, Zhang L, Li W, Wang C, Li X. Comprehensive analysis of fatty alcohol ethoxylates by ultra high pressure hydrophilic interaction chromatography coupled with ion mobility spectrometry mass spectrometry using a custom-designed sub-2 μm column. J Sep Sci. 2015;38(12):2182–91. https://doi.org/10.1002/jssc.201500185.
- 27.West C, Lesellier E. Characterisation of stationary phases in subcritical fluid chromatography with the solvation parameter model: III. Polar stationary phases. J Chromatogr A 2006;1110(1):200–213. doi: https://doi.org/10.1016/j.chroma.2006.01.109.
- 28.Berger TA. Characterization of a 2.6 μm Kinetex porous shell hydrophilic interaction liquid chromatography column in supercritical fluid chromatography with a comparison to 3 μm totally porous silica. J Chromatogr A. 2011;1218(28):4559–68. https://doi.org/10.1016/j.chroma.2011.04.071.CrossRefGoogle Scholar
- 29.Emmett MR, Kazazic S, Marshall AG, Chen W, Shi SD, Bolaños B, Greig MJ. Supercritical fluid chromatography reduction of hydrogen/deuterium back exchange in solution-phase hydrogen/deuterium exchange with mass spectrometric analysis. Anal Chem. 2006;78(19):7058–60. https://doi.org/10.1021/ac060693n.
- 30.de la Puente ML, Soto-Yarritu PL, Anta C. Placing supercritical fluid chromatography one step ahead of reversed-phase high performance liquid chromatography in the achiral purification arena: a hydrophilic interaction chromatography cross-linked diol chemistry as a new generic stationary phase. J Chromatogr A. 2012;1250:172–81. https://doi.org/10.1016/j.chroma.2012.03.050.CrossRefGoogle Scholar