Constant-wavelength synchronous fluorescence spectrometry for simultaneous and rapid determination of five polycyclic aromatic hydrocarbon residues in dairy products

摘要

A new method for simultaneously determining five polycyclic aromatic hydrocarbons (PAHs) (fluorene, benzofluorene, pyrene, benzo(a)pyrene, and perylene) in dairy products using constant-wavelength synchronous fluorescence spectrometry (CWSFS) was established in this study. Acetonitrile was chosen as the extraction solvent to extract the five PAHs from the dairy products, and an ultrasound extraction method was adopted. The supernatants were filtered using a 0.45-mu m microporous filter membrane and concentrated to dryness with a nitrogen dryer. The extracts were then re-dissolved in cyclohexane for analysis. To overcome interference from the background matrix and between PAHs, the difference in wavelength (Delta lambda) at 40 nm was chosen for CWSFS scanning. With only one single scan, the five PAHs in dairy products could be distinguished and determined using the standard curve method without the need for previous chromatographic separation of the analyte solution. Detection limits of fluorene, benzofluorene, pyrene, benzo(a)pyrene, and perylene were 0.0051 mu g center dot L-1, 0.016 mu g center dot L-1, 0.021 mu g center dot L-1, 0.0056 mu g center dot L-1, and 0.0062 mu g center dot L-1, respectively. Recoveries were between 85.60% and 98.42%. These five PAHs in dairy products were determined with good results and therefore expected to be a routine detection method for PAHs in dairy products.