A novel HPLC flow cell integrated UV light emitting diode induced fluorescence detector as alternative for sensitive determination of aflatoxins

摘要

A novel UV light emitting diode induced fluorescence detector (LED-IF) with HPLC flow cell was designed and evaluated for determination of aflatoxins. Ray tracing method was employed to optimize the design of the optical components (such as reshaping thin lens for light source and fluorescence collection), and optical structure, and the geometry of flow cell. An ordinary UV LED with wavelength of 370?nm and radiant power of 5?mW was used as excitation light source. A photoelectric amplifierAccuOpt2000with light sensitivity of 10?5～10?4lxwas utilized for fluorescence detection, instead of a photo multiplier tube (PMT). The lowest detection limit (LOD) of the LED-IF was 0.077?ppb for aflatoxin B1by HPLC method without derivatization. The LED-IF was then coupled with a homemade iodine derivatization device, which was connected to the HPLC column outlet for determination of aflatoxins in edible oil and peanut samples. It was found that the edible oil sample contained aflatoxin B1and B2at average level of 7.14 (n?=?3) and 0.30?ng/g (n?=?3), respectively; while the peanut sample contained aflatoxin B1and B2at average level of 9.22 (n?=?3) and 1.36?ng/g (n?=?3), respectively. The overall power consumption of the LED-IF was 1?W/12?V. The sensitivity of the LED-IF was similar to commercial fluorescence detectors, which utilized a pulse Xe lamp as excitation light source and a PMT for detection, with power consumption of 150?W.