TY - JOUR
T1 - Abnormal behaviors in the calibration curves of liquid chromatography–tandem mass spectrometry occurring in the quantitative analysis of surfactants near critical micelle concentrations
AU - Lee, Sang Tak
AU - Kim, Hyeri
AU - Kwon, Jung Hwan
AU - Oh, Han Bin
N1 - Funding Information:
This work was supported by grants from the National Research Foundation of Korea (NRF) funded through Basic Science Research Program (2018R1A6A1A03024940 and 2018R1A2B6005707) and also by Korea Environment Industry & Technology Institute (KEITI) through Technology Program for Establishing Biocide Safety Management (2018002490001) and Technology Development Program for Safety Management of Household Chemical Products (2020002960004), funded by Korea Ministry of Environment (MOE).
Publisher Copyright:
© 2020 John Wiley & Sons, Ltd.
PY - 2021/4
Y1 - 2021/4
N2 - Surfactants, including quaternary ammonium compounds, are widely used in daily life as part of consumer chemical products and, more recently, in the shale oil industry. Because of their unique amphiphilic properties, surfactants form micelles at concentrations above a certain threshold known as the critical micelle concentration (CMC). A previous electrospray ionization mass spectrometry studies conducted by Siuzdak et al. and others presented indirect evidence regarding micelle formation. Herein, we have used liquid chromatography–tandem mass spectrometry to explore how such micelle formations affect the quantitative analysis of surfactants. Results reveal abnormal behaviors in the calibration plots of a few selected anionic and cationic surfactants, such as sodium decyl sulfate (SDeS), sodium dodecyl sulfate (SDS), myristyltrimethylammonium bromide (MTAB), and benzyldimethyloctadecylammonium chloride (BAC-18). At concentrations close to the respective CMCs of these surfactants, the calibration plot for MTAB flattened, whereas the slopes of the calibration plots for SDeS, SDS, and BAC-18 suddenly changed. These abnormal behaviors can be related to micelle formation. From a practical perspective, the above observations suggest that in the quantitative analysis of surfactants, high micelle concentrations close to the CMC should be avoided to obtain accurate surfactant measurements.
AB - Surfactants, including quaternary ammonium compounds, are widely used in daily life as part of consumer chemical products and, more recently, in the shale oil industry. Because of their unique amphiphilic properties, surfactants form micelles at concentrations above a certain threshold known as the critical micelle concentration (CMC). A previous electrospray ionization mass spectrometry studies conducted by Siuzdak et al. and others presented indirect evidence regarding micelle formation. Herein, we have used liquid chromatography–tandem mass spectrometry to explore how such micelle formations affect the quantitative analysis of surfactants. Results reveal abnormal behaviors in the calibration plots of a few selected anionic and cationic surfactants, such as sodium decyl sulfate (SDeS), sodium dodecyl sulfate (SDS), myristyltrimethylammonium bromide (MTAB), and benzyldimethyloctadecylammonium chloride (BAC-18). At concentrations close to the respective CMCs of these surfactants, the calibration plot for MTAB flattened, whereas the slopes of the calibration plots for SDeS, SDS, and BAC-18 suddenly changed. These abnormal behaviors can be related to micelle formation. From a practical perspective, the above observations suggest that in the quantitative analysis of surfactants, high micelle concentrations close to the CMC should be avoided to obtain accurate surfactant measurements.
KW - LC-MS
KW - mass spectrometry
KW - micelle
KW - micelle formation concentration (CMC)
KW - quaternary ammonium compound (QAC)
KW - surfactant
UR - http://www.scopus.com/inward/record.url?scp=85088153585&partnerID=8YFLogxK
U2 - 10.1002/jms.4599
DO - 10.1002/jms.4599
M3 - Article
C2 - 32677769
AN - SCOPUS:85088153585
VL - 56
JO - Journal of Mass Spectrometry
JF - Journal of Mass Spectrometry
SN - 1076-5174
IS - 4
M1 - e4599
ER -