Development of a solid-phase cleanup and portable rapid flow-through enzyme immunoassay for the detection of ochratoxin a in roasted coffee.
A membrane-based flow-through enzyme immunoassay (patent application pending) for the detection of ochratoxin A (OA) in roasted coffee was developed. First, an extraction and solid-phase cleanup method was developed. A high partition coefficient for OA in the mobile phase was achieved by using methanol/5% aqueous NaHCO(3) as the sample extraction and cleanup solvent. The solid-phase (aminopropyl) cleanup was developed to chromatographically elute OA but retain cross-reacting compounds. Without using aminopropyl cleanup, cross-reacting compounds resulted in 100% false positives for both flow-through enzyme immunoassay and HPLC methods. However, after cleanup with aminopropyl, no false positives were observed. The flow-through results were visually evaluated. The sensitivity achieved for the flow-through was 4 microg kg(-1) in spiked roasted coffee. The assay was used to screen roasted coffee samples. Results were confirmed with HPLC with a detection limit of 1 microg kg(-1).
Sibanda
Liberty
L
Laboratory of Food Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium.
De Saeger
Sarah
S
Barna-Vetro
Ildiko
I
Van Peteghem
Carlos
C
D002851:Chromatography, High Pressure Liquid; D040503:Coffea / Q000737:chemistry*; D005189:False Positive Reactions; D006358:Hot Temperature; D007124:Immunoenzyme Techniques / Q000379:methods*; D009793:Ochratoxins / Q000032:analysis*; D012639:Seeds / Q000737:chemistry*; D017693:Sodium Bicarbonate; D012997:Solvents
D009793:Ochratoxins; D012997:Solvents; C025589:ochratoxin A; D017693:Sodium Bicarbonate