Determination of phenolic compounds derived from hydrolysable tannins in biological matrices by RP-HPLC.

An RP-HPLC method for the determination of four phenolic compounds: gallic acid (GA), pyrogallol (PY), resorcinol (RE) and ellagic acid (EA), derived from hydrolysable tannins is reported. Separation was achieved on a SunFire C18 (250 x 4.6 mm id, 5 microm) column at 40 degrees C with gradient elution.

Simultaneous determination of adenine and guanine in ruminant bacterial pellets by ion-pair HPLC.

An ion-pair reversed-phase high-performance liquid chromatography with gradient elution and UV detection was used to measure adenine (A) and guanine (G) in lyophilized bacterial pellets from ruminants using allopurinol as internal standard. The separation was performed on a Symmetry C18 column and the detection was monitored at 280 nm. Calibration curves were found to be linear in the concentration range from 5 to 50 mg/l with correlation coefficients (r2)>0.