Validation of Analytical Method Determination of Sodium Dodecyl Benzene Sulfonate (DBS) in Catfish (Clarias batrachus L.) by Spectrophotometric Using Methylene Blue

A spectrophotometric method for analysis of DBS anionic surfactant in Clarias batracus has been validated. The method of analysis was divided into two phases. Extraction with solid-liquid extraction using Soxhlet and analysis of DBS. The extraction was performed using solvent of n-hexane and methanol for 9 and 6 hours, respectively. The analysis was performed using Spectrophotometer UV-Vis based on the complex formation of DBS-methylene blue (DBS-MB). This methods is applied to the determination of DBS in local catfish after DBS exposure and that of obtained in markets. The results showed that the parameters of validation methods have high acceptability as linierity (R2 = 0.99), limit of detection (LOD) and limit of quantification (LOQ ) (2.93 mg/g and 9.75 mg/g), sensitivity (ε = 2.44 x 105 L mol-1 cm-1), precision (RSD = 0.14-1.38%) and accuracy (% recovery in a range 82-110 %). The results of analysis of DBS in catfish with 2.5; 5; 10; 15 mg/L of DBS concentration exposure are 0.87; 1.67; 8.50 and 18.10 mg/kg, respectively and catfish from markets in a range 8.5-61 mg/kg. The result showed that the method of analysis of DBS anionic surfactant using MB could be applied for catfish samples.