Quantification of phosphate content in commercial dishwashing detergents available in malaysia using the molybdenum blue method

Phosphates are commonly used in dishwashing as water softeners, but their excessive release into water bodies contributes to eutrophication and water quality decline. Despite global regulations, phosphate-based dishwashers remain common in countries like Malaysia with minimal oversight. This study used the molybdenum blue method to quantify phosphate levels in five commercial dishwashing products (Brands A–E) sold in Malaysia. Samples were diluted (1:200), and phosphate concentrations were measured using a calibration curve (0–5 mg/L PO₄³⁻) at 650 nm. The method showed strong linearity (R² = 0.9885) and good precision (RSD < 10%). Phosphate content ranged from 0.115 to 0.199 mg/L, with Brand E highest. Based on 5 mL usage per wash with 10–15 L water, estimated phosphate discharge ranged from 0.575 to 0.995 mg. Though low per use, repeated widespread use can increase nutrient loading in aquatic systems. Findings stress the need for awareness, regulation, and product reformulation to reduce phosphate pollution.