Vacuum centrifugal concentrator

The equipment and manufacturers used in the study were as follows: EMKA non-invasive electrocardiography telemetry system (Beijing GYD Labtech Co., Ltd., China), AU480 automatic biochemical analyzer (Olympus Corporation, Japan), DNM-9602G enzyme micro-plate reader (Beijing Perlong, China), DNX-9620A computer board washer, ABS2TM automatic blood collection instrument and ABS2 software (Instech Laboratories, Inc, United States), Mix-3000 shock mixer (Hangzhou Mio Instrument Co., Ltd., China), Mikro 220R high-speed refrigerated centrifuge (Hettich Scientific Instruments, Germany), and vacuum centrifugal concentrator (Thermo Scientific, United States).

To detect the urate and purine contents of the liver, kidney and feces, 200 mg of sample was added to 5 mL trifluoroacetic acid, 5 mL formic acid, and 10 mL H₂O and hydrolyzed at 90 °C for 15 min. After hydrolysis, the hydrolysate was cooled quickly, and the solvent was dried using a vacuum centrifugal concentrator (Thermo Fisher Scientific, Waltham, MA, USA). The sample was redissolved in the mobile phase and filtered through a 0.45 μm filter disk. HPLC analysis was performed using an Agilent 1200 series HPLC System. Sample solution (20 μL) was injected onto an Aq-C18 column (4.6 mm × 250 mm, 5 μm) (Agilent, Santa Clara, CA, USA). Elution was carried out using 0.007 mol/L KH₂PO₄-H₃PO₄. The column was maintained at room temperature. The flow rate was 1 mL/min, and detection was performed at 254 nm.