Analysis of wheat extracts for ochratoxin A by molecularly imprinted solid-phase extraction and pulsed elution.
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-microL 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 lambda(ex)=385 nm and lambda(em)=445 nm, afforded a detection limit of 5.0 ng mL(-1) (or 0.1 ng in 20 microL 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.
Zhou
Simon N
SN
Ottawa-Carleton Chemistry Institute, Department of Chemistry, Carleton University, ON K1S 5B6, Ottawa, Canada.
Lai
Edward P C
EP
Miller
J David
JD
D020106:Acrylamide / Q000737:chemistry; D002138:Calibration; D002846:Chromatography, Affinity / Q000295:instrumentation*; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D009793:Ochratoxins / Q000032:analysis* / Q000737:chemistry* / Q000302:isolation & purification; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013997:Time Factors; D014908:Triticum / Q000737:chemistry*
D009793:Ochratoxins; D011108:Polymers; C025589:ochratoxin A; D020106:Acrylamide