Rapid and sensitive determination of trace chloride ion in drinks using resonance light scattering technique

A resonance light scattering (RLS) technique to determine chloride ions in drinks was developed. Chloride ions were found to bind Ag(+) forming AgCl aggregates that produced intense resonance scattering light. Effects of factors such as acidity, ionic strength, and coexistent interferents on the RLS of AgCl aggregates were investigated. The pH of solution almost did not affect the production of RLS and few foreign species interfered with the detection of chloride ions. The resonance scattering light intensity at the maximum peak of 571 nm was linear to the concentration of chloride ions in the range of 1.42-8.52 ng mL(-1) with a detection limit of 0.71 ng mL(-1). To determine the feasibility of the proposed method, some samples of water and drinks were analyzed. The attained results were in agreement with that of ion-selective electrode method. Good recovery results were also obtained with the range of 94.08-105.63%. The sensitivity and selectivity of the RLS method are high enough to determine trace amounts of chloride ions without any significant interference from high concentration of other components such as common anions and cations.