Determination of polycyclic aromatic hydrocarbons in food samples by automated on-line in-tube solid-phase microextraction coupled with high-performance liquid chromatography-fluorescence detection.
A simple and sensitive automated method, consisting of in-tube solid-phase microextraction (SPME) coupled with high-performance liquid chromatography-fluorescence detection (HPLC-FLD), was developed for the determination of 15 polycyclic aromatic hydrocarbons (PAHs) in food samples. PAHs were separated within 15 min by HPLC using a Zorbax Eclipse PAH column with a water/acetonitrile gradient elution program as the mobile phase. The optimum in-tube SPME conditions were 20 draw/eject cycles of 40 microL of sample using a CP-Sil 19CB capillary column as an extraction device. Low- and high-molecular weight PAHs were extracted effectively onto the capillary coating from 5% and 30% methanol solutions, respectively. The extracted PAHs were readily desorbed from the capillary by passage of the mobile phase, and no carryover was observed. Using the in-tube SPME HPLC-FLD method, good linearity of the calibration curve (r>0.9972) was obtained in the concentration range of 0.05-2.0 ng/mL, and the detection limits (S/N=3) of PAHs were 0.32-4.63 pg/mL. The in-tube SPME method showed 18-47 fold higher sensitivity than the direct injection method. The intra-day and inter-day precision (relative standard deviations) for a 1 ng/mL PAH mixture were below 5.1% and 7.6% (n=5), respectively. This method was applied successfully to the analysis of tea products and dried food samples without interference peaks, and the recoveries of PAHs spiked into the tea samples were >70%. Low-molecular weight PAHs such as naphthalene and pyrene were detected in many foods, and carcinogenic benzo[a]pyrene, at relatively high concentrations, was also detected in some black tea samples. This method was also utilized to assess the release of PAHs from tea leaves into the liquor.
Ishizaki
A
A
School of Pharmacy, Shujitsu University, 1-6-1, Nishigawara Naka-ku, Okayama 703-8516, Japan.
Saito
K
K
Hanioka
N
N
Narimatsu
S
S
Kataoka
H
H
D001331:Automation; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D005504:Food Analysis / Q000295:instrumentation / Q000379:methods*; D005506:Food Contamination / Q000032:analysis; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000302:isolation & purification; D052617:Solid Phase Microextraction / Q000295:instrumentation / Q000379:methods*
D011084:Polycyclic Aromatic Hydrocarbons