Analysis of wheat extracts for ochratoxin A by molecularly imprinted solid-phase extraction and pulsed elution
- 291 Downloads
A molecularly imprinted solid-phase extraction (MISPE) method has been developed for the rapid analysis of wheat extracts for ochratoxin A (OTA). Molecularly imprinted polymer (MIP) particles were synthesized from N-phenylacrylamide (PAM) and slurry-packed into a micro-column for selective solid-phase extraction (SPE) of OTA. With water flowing at 0.5 mL min−1, a total binding capacity of 30 ng OTA was determined for the 20 mg of MIP particles. MISPE conditions were optimized using OTA in methanol/acetic acid (99:1 v/v). Nearly 100% binding could be achieved from one 20-μL injection of sample containing up to 30 ng of OTA. Pulsed elution (PE) using methanol/triethylamine (99:1 v/v) was good for the quantitative desorption of OTA. The MISPE–PE method, with fluorescence detection at λ ex=385 nm and λ em=445 nm, afforded a detection limit of 5.0 ng mL−1 (or 0.1 ng in 20 μL of sample injected) for OTA. Recovery of OTA from wheat extracts was 103±3%. Each MISPE–PE analysis required less than 5 min to complete.
KeywordsOchratoxin A Molecularly imprinted polymer Solid-phase extraction Pulsed elution Wheat extracts Rapid screening
Financial support of the Natural Sciences and Engineering Research Council (NSERC) Canada is gratefully acknowledged. The authors thank Tom Nowicki and Mike Roscoe, Winnipeg Food Inspection Agency, for the wheat extracts and helpful discussions.
- 1.http://www.lfra.co.uk/eman/fsheet2_1.htm. Cited 1 Sept 2003Google Scholar
- 2.OAC (1990) Ochratoxin A in green coffee 975.38Google Scholar
- 6.vanderGaag B, Spath S, Dietrich H, Stigter E, Boonzaaijer G, van Osenbruggen T, Koopal K (2003) Food Control 14:251–254Google Scholar
- 8.Shea KJ, Yan M, Roberts MJ (eds) (2002) Molecularly imprinted materials—sensors and other devices. Materials Research Society, Warrendale, PAGoogle Scholar
- 11.Mullett WM, Lai EPC (1998) Anal Chem 70:3636–3641Google Scholar
- 18.Wu SG, Lai EPC, Mayer PM (2003) J Pharm Biomed Anal (in press)Google Scholar
- 22.Zhou SN, Lai EPC (2003) N-Phenylacrylamide functional polymer with high affinity for ochratoxin A. React Funct Polym (submitted)Google Scholar
- 24.Russel H (1986) Ruckstandsanalytic von wirkstoffen in tierischen produkten. Georg Tieme Verlag, StuttgartGoogle Scholar