Ultrasonic extraction with ultra-performance liquid chromatography/tandem mass spectrometry for the determination of ochratoxin A in processed cereal products.

A rapid, simple, and reliable method using ultra-performance LC/MS/MS (UPLC/MS/MS) was developed for determination of ochratoxin A (OTA) in processed cereal products. OTA was ultrasonically extracted from the sample with acetonitrile-water (80 + 20, v/v), and the extract was then injected into the UPLC/MS/MS system after filtration. The calibration curves had good linearity with coefficients of determination greater than 0.

Development of a stir bar sorptive extraction method for analysis of ochratoxin A in beer.

A new, simple, and sensitive method was developed for extraction of ochratoxin A (OTA) in beer combined with HPLC-fluorescence detector. Samples were extracted by stir bar sorptive extraction (SBSE) followed by liquid desorption using commercially available Twister EG-Silicone. The main parameters influencing SBSE, including phase ratio, extraction time, stirring speed, ionic strength, organic modifier, pH, temperature, desorption mode, desorption solvent, and desorption time were optimized.

Rapid and selective determination of UV filters in seawater by liquid chromatography-tandem mass spectrometry combined with stir bar sorptive extraction.

Fast liquid chromatography coupled to triple-quadrupole tandem mass spectrometry was employed for the determination of six UV filters in seawater. The separation of the analytes was achieved in less than 5 min; polarity switching was used as four of the analytes were ionized in positive mode and the remaining two in negative mode. Two ionization sources were employed and compared: atmospheric pressure chemical ionization (APCI) gave better results than electrospray ionization (ESI) for all analytes, with higher reproducibility and lower detection limits.