Potentiometric and spectrophotometric determination of phosphoric acid in some beverages

The Potentiometric and spectrophotometric determination of phosphoric acid content was conducted on three batches of selected beverages: Regular and Light Coke, Regular and Light Pepsi, Smirnoff Ice and 7 Up with 7 Up as control. The phosphoric acid content (mg P/L) in the three batches of these beverages using potentiometric method were: Light Coke - 136.9±5.9, 139.500±0, 139.500±0; Regular Coke - 183.4±3.9, 175.2±0.8, 174.4±2.3; Light Pepsi - 170.5±2.1, 172.8±3.6, 164.6±2.0; Regular Pepsi - 139.8±4.5, 141.6±3.1, 140.0±0.9; Smirnoff Ice - 2244.9±44.7, 2166.9±40.6, 2087.3±28.6. The results of the spectrophotometric method were respectively: Light Coke - 226.7±3.7, 207.2±1.8, 224.6±2.0; Regular Coke - 218.4±2.7, 271.8±3.3, 242.7±1.6; Light Pepsi - 220.4±2.4, 252.9±2.3, 254.9±1.2; Regular Pepsi - 237.3±1.4, 256.2±1.2, 255.6±1.8; Smirnoff Ice – 916.1±25.5, 969.1±10.7, and 923.2±19.7. 7 Up however, did not contain phosphoric acid. Analyses of variance using Student’s t test showed that at 0.05 level, there was no significant statistical difference between the two methods employed as TcalHtab (7.20 > 5.99). The extremely low pH values of the beverages (2.15 – 2.85) may account for the claims of authors of being associated with cariogenicity. The phosphoric acid contents of these beverages (207.241±1.751 – 969.147±10.743 mg.P/L) pose some health concern.

Author(s): Pius I. Utange, Raymond A. Wuana and Timothy V. Akpoghol

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