Supervisors info:
Ιωάννης Παπαδογιάννης, Καθηγητής, Τμήμα Χημείας, Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης
Summary:
A quick, easy, cheap, effective, rugged and safe (QuEChERS) dispersive extraction method was applied for the selective isolation and clean-up of tetracyclines (oxytetracycline, tetracycline, chlorotetracycline and doxycycline) from milk. Target analytes were determined by an accurate and sensitive chromatographic analytical method, which was validated in terms of 657/2002/EC decision. The separation was achieved using an Orbit 100C4 (5 μm, 250 × 4.0 mm) analytical column with a gradient mobile phase consisting of a mixture of 0.01 M oxalic acid, 10-4 M Na2EDTA and acetonitrile. Extraction of isolated compounds was achieved by methanol and 0.01M oxalic acid mixture (1:1 v/v). Recovery rates ranged between 82.4% and 106.3%. The within-laboratory reproducibility, expressed as a relative standard deviation, was <15.5%. Decision limits ranged between 100.3 μg/kg and 105.6 μg/kg and the detection capability between 100.6 μg/kg and 109.7 μg/kg. Ruggedness was estimated according to the Youden approach studying milk mass, sorbent mass, centrifugation time, vortex time, type and volume of organic solvents and evaporation temperature.
Keywords:
tetracyclines, milk, HPLC, QuEChERS, validation
