(a) Protocatechuic acid
(b) Vanillic acid
(c) Synringic acid
(d) Vanillin
Figure 3: Quantitative HPLC analysis of polyphenols extracted from the cattle excrement at 150, 200, 250 and C. (a) protocatechuic acid, (b) vanillic acid, (c) syringic acid, and (d) vanillin. The circles show the yield of plant polyphenol per 1 g of excrement. A reversed-phase column (Shimadzu Shim-Pack CLC-ODS; = 6.0 mm; column length, 150 mm) was used at the temperature of C. An aqueous solution of 2902.95 mL , 31.5 mL methanol, and 5.55 mL propan-2-ol, 60 mL acetic acid, 8.17 g sodium acetate was used as a mobile phase. UV absorbance was detected at 280 nm.