The determination of Benzo(a)pyrene in oil generally used prepacked alumina column, and big volume of elution is needed and take lots of labor and time.
Bonna-Agela developed a new SPE product with much more convenient method. The main challenge is to extract hydrophobic Benzo(a)pyrene from oil matrix. Hexane was chosen as the best solvent to dissolve vegetable oil after investigation.
In the new method, 0.5 g vegetable oil was dissolved in 3 mL hexane and loaded onto the Cleanert® BAP-3 cartridge. 10mL hexane was used to wash the cartridge and 5mL methylene chloride to elute the Benzo(a)pyrene out. After drying the eluant with nitrogen blowing, 1mL acetonitrile was used to reconstitute the sample. The detection was carried out on HPLC with fluorometric detection. In addition, sesame oil contained more impurities which was need to be treated with Cleanert® SI (500 mg/6 mL) firstly. This new method show better performance, and could be used for many kinds of vegetable oil.
Take 0.5g of oil sample in 12ml vial. Then added 3mL hexane and shocked it with ultrasound instrument to get the extraction solution. Spiked with Benzo(a)pyrene standard solution into 0.5g oil sample if recovery investigation of Benzo(a)pyrene was needed.
Condition: 5ml Dichloromethane and 5ml Hexane;
Load all the 0.5g sample onto the cartridge;
Washing: 10mL Hexane;
Elution: 5mL Dichloromethane.
Collected the eluant in 12 mL vial and dried it by Nitrogen blowing at 40 °C. Then 1mL Acetonitrile was added to reconstitute it. After 10s treatment by ultrasound and filtration by 0.22 μm PTFE syringe filter, then for further analysis.
This method is adapt to peanut oil, soybean oil, corn oil, sunflower oil, rice oil, sesame oil, cooking oil, canola oil and olive oil. For sesame oil, and another Cleanert® Si (500mg/6mL, P/N:Si5006) cartridge was needed to place onto the Cleanert® BAP-3 cartridge, use the same process as describe upside and remove the Silica cartridge before elution.
HPLC Column: Venusil® ASB C18, 4.6 mm × 250 mm × 5.0 μm (P/N: VS952505-0);
Mobile phase: Acetonitrile: Water (88/12, V/V);
Flow rate: 1.0 mL/min;
Injection sample: 20 μL;
Fluorescence Detector: excitation spectrum 384, emission spectrum 406;
Column temperature: 30 °C
Results and Discussion
Table1 Recovery of Benzo(a)pyrene
A new detection method of Benzo(a)pyrene in Vegetable oil was developed with Cleanert® BAP-3 cartridge which was simple, quick and easily to be handled. The recovery rates of the method were between 84.1%~92.2% for 1 μg/L, 5 μg/L and 10 μg/L concentrations.