Highly sensitive determination of chloride ions in serum using a Rayleigh light scattering technique

A Rayleigh light scattering technique to determine chloride ions in serum was developed. Chloride ions were found to bind Ag+ forming an AgCl aggregate that produced intense Rayleigh scattering light. The effects of factors such as acidity, ionic strength and coexisting interferents on the RLS of the AgCl aggregate were investigated. The solution pH almost did not affect the production of RLS, and few foreign biologically relevant species interfered with the detection of chloride ions. The Rayleigh scattering light intensity at the maximum peak of 571 nm was linear to the concentration of chloride ions in the range of 35.5–71.0 ng mL−1 with a detection limit of 14.2 ng mL−1. The method was applied to determine chloride ions in serum, showing high sensitivity and accuracy compared with the clinically used ion-selective electrode method.