HPTLC Screening of Folic Acid in Food: In Situ Derivatization with Ozone-Induced Fluorescence
This paper proposes a facile and specific method tailored for quantifying and confirming folic acid in food, based on the combination of high-performance thin layer chromatography with fluorescence densitometry and surface-enhanced Raman spectroscopy. Chromatography was carried out on silica gel plates, using methanol/ethyl acetate/ammonia (6:4:1, v/v/v) as the mobile phase. For the first time, ozone gas was utilized as the derivative agent, which efficiently induced the appearance of strong fluorescence of the analyte. Thereafter, fluorescent densitometry measurements were carried out for quantitative purpose, offering good linearity (R2 > 0.999) and sensitivity (0.7–1.4 mg/kg). In addition, the applicability and reliability of the established method was validated with food and food supplement samples, showing good agreement with the data obtained by conventional HPLC-UV as the benchmark, but with remarkably higher efficiency. Apart from that, the in situ-obtained surface-enhanced Raman spectroscopic fingerprint of bands under optimized conditions (532-nm incident laser and tenfold concentrated silver nanoparticles) enabled unambiguous identification of the targeted compound, serving as a convenient and affordable tool to prevent potential mistake from false-positive results.
KeywordsFolic acid Ozone HPTLC SERS
Particularly, we would like to express sincere thanks to CAMAG “Dieter Jänchen” prize which bridged excellent cooperation of authors.
This work was financially supported by the National Key Research and Development Program (2017YFC1601004 and 2017YFF0207800), the National Natural Science Foundation of China (21804058), and the Natural Science Foundation of Jiangsu Province (BK20170177). Also, CAMAG “Dieter Jänchen” prize supported this study.
Compliance with Ethical Standards
Conflict of Interest
Ping Wang declares that he has no conflict of interest. Yisheng Chen declares that he has no conflict of interest. Xueming Xu declares that he has no conflict of interest. Bernhard Hellmann declares that he has no conflict of interest. Caihong Huang declares that he has no conflict of interest. Yuxiang Bai declares that he has no conflict of interest. Zhengyu Jin declares that they he has no conflict of interest.
This article does not contain any studies with animals performed by any of the authors.
Informed consent is not applicable in this study.
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