Analysis of sodium benzoate and potassium sorbate in local brands of pre-packed pineapple juices using UV-VIS spectrophotometry

Date of Publication


Document Type

Bachelor's Thesis

Degree Name

Bachelor of Science in Chemistry

Subject Categories



College of Science



Thesis Adviser

Julita C. Robles

Defense Panel Member

Lazaro-Llanos, Nancy Llanos Lazaro

Derrick Ethelbert C. Yu


UV-VIS Spectrophotometry was used to analyze the chemical preservatives sodium benzoate and potassium sorbate present in two local brands of pre-packed pineapple juices purchased in Manila and Muntinlupa. The maximum limit set by the Bureau of Food and Drugs for sodium benzoate and potassium sorbate in food are 0.1 % (5mg/5 mL) and 0.3 % (15mg/mL) respectively. The AOAC Official Method 980.17 (Preservatives in Ground Beef) was adapted for the quantitative determination of these preservatives. Standard solutions of sodium benzoate and potassium sorbate were extracted using petroleum ether and 1:1 M hydrochloric acid and the absorbance of the standard and sample solutions were measured at 2גּmax = 228 (benzoic acid) and גּmax = 255 (sorbic acid). Results show that Brand X (Manila) contains 0.295 mg/mL sodium benzoate (2.00 % RSD) and 0.0853 mg/5 mL potassium sorbate (3.70 % RSD) while Brand X (Muntinlupa) contains 0.0878 mg/5mLsodium benzoate (6.00 & RSD) and 0.278 mg/5mL potassium sorbate (9.10% RSD). Brand Y (Manila) contains 0.321 mg/5mL sodium benzoate (4.50 %RSD) and 0.0212 mg/5mL potassium sorbate (2.30 %RSD) while Brand Y (Muntinlupa) contains 0.0197 mg/5mL sodium benzoate (6.60 % RSD) and 0.113 mg/5mL potassium sorbate (5.60 % RSD). The concentration of these additives in the juice samples were found to be within the limits set by the Bureau of Food and Drugs. Standard addition was found to be not suitable because of the significant deviations from linearity between the absorbance and concentration of the added standard solution.

Abstract Format






Accession Number


Shelf Location

Archives, The Learning Commons, 12F, Henry Sy Sr. Hall

Physical Description

90, [4] leaves : illustrations (some color) ; 28 cm.


Sodium benzoate; Benzoates; Potassium; Spectrophotometry; Pineapple; Fruit juices

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