Humic acids as both matrix for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and adsorbent for magnetic solid phase extraction.
In the present study, humic acids (HAs) were applied as both a matrix for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and an adsorbent of magnetic solid phase extraction (MSPE) for the first time. As natural macromolecule compounds, HAs are inherently highly functionalized and contain laser energy absorbing-transferring aromatic structures. This special molecular structure made HAs a good candidate for use as a MALDI matrix in small molecule analysis. At the same time, due to its good adsorption ability, HAs was prepared as MSPE adsorbent via a simple co-mixing method, in which the commercially available HAs were directly mixed with Fe3O4 magnetic nanoparticles (MNPs) in a mortar and grinded evenly and completely. In this process, MNPs were physically wrapped and adhered to tiny HAs leading to the formation of magnetic HAs (MHAs). To verify the bi-function of the MHAs, Rhodamine B (RdB) was chosen as model compound. Our results show that the combination of MHAs-based MSPE and MALDI-TOF-MS can provide a rapid and sensitive method for the determination of RdB in chili oil. The whole analytical procedure could be completed within 30 min for simultaneous determination of more than 20 samples, and the limit of quantitation for RdB was found to be 0.02 μg/g. The recoveries in chili oil were in the range 73.8-81.5% with the RSDs less than 21.3% (intraday) and 20.3% (interday). The proposed strategy has potential applications for high-throughput analysis of small molecules in complex samples.
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, China; Department of Preventive Medicine, School of Medicine, Wuhan University of Science and Technology, Wuhan 430074, China.
Qin
Q
Zhao
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, China.
Jing
J
Xu
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, China.
Jia
J
Yin
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, China. Electronic address: yqfeng@whu.edu.cn.
Yu-Qi
YQ
Feng
D000327:Adsorption; D002851:Chromatography, High Pressure Liquid; D052203:Ferrosoferric Oxide / Q000737:chemistry; D006812:Humic Substances / Q000032:analysis*; D057230:Limit of Detection; D058185:Magnetite Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D009822:Oils, Volatile / Q000737:chemistry; D015203:Reproducibility of Results; D012235:Rhodamines / Q000032:analysis / Q000302:isolation & purification; D052616:Solid Phase Extraction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D006812:Humic Substances; D058185:Magnetite Nanoparticles; D009822:Oils, Volatile; D012235:Rhodamines; C029773:rhodamine B; D052203:Ferrosoferric Oxide
Humic acids; Magnetic solid phase extraction; Matrix; Rhodamine B