A highly sensitive and simple Rayleigh light scattering (RLS) method for the determination of ciprofloxacin hydrochlo-ride has been developed. Ciprofloxacin hydrochloride (CPFH) reacted with tetraphenylboron sodium(TPB) to form an ion-association complex in pH 5.31 aqueous solution, which re-sulted in a significant enhancement of the RLS intensity, which was linear with the concentration of CPFH in the range of 12.7-419 ng·mL-1. The limit of detection for CPFH was 6.99 ng·mL-1. The method is simple, highly sensitive and selective within a wide linear range. Applying this method for the determi-nation of ciprofloxacin hydrochloride in pharmaceutical prepara-tions and biological fluids obtained satisfactory results.
