Aptamer based extraction followed by electrospray ionization-ion mobility spectrometry for analysis of tetracycline in biological fluids

An extraction method based on aptamer sorbent followed by electrospray ionization-ion mobility spectrometry (ESI-IMS) has been developed for the analysis of tetracycline in human urine and plasma samples. The effect of extraction parameters on the extraction efficiency including washing (solvent type and volume) and elution (solvent type, volume and flow rate) were investigated. Under the optimized conditions, the linear dynamic ranges for tetracycline in urine and plasma samples were found to be 0.05–5.00 μg/mL and 0.10–5.00 μg/mL with detection limits of 0.019 and 0.037 μg/mL, respectively. The extraction efficiency was 86.5% for urine and it was 82.8% for plasma samples. The relative standard deviation was 5.9% and 6.3% for six replicate measurements of tetracycline at 1 and 2 μg/mL in urine and plasma samples, respectively.