Determination of Sodium Carboxymethyl Cellulose in Dairy Products by Resonance Rayleigh Scattering Spectrometry

In the weakly alkaline medium, sodium carboxymethyl cellulose (NaCMC) can react with fuchsin to form a large volume ion-association complex. As a result of the reaction, intensity of resonance Rayleigh scattering ( I RRS ) was enhanced significantly and a new RRS spectrum appeared. Two maximum scattering peaks were located at 320 nm and 600 nm for fuchsin–NaCMC. Under optimal conditions, there is a linear relationship between the relative intensity of RRS and the concentration of NaCMC in the range of 0 ~ 10.0 mg/L. The regression equation was ΔI RRS = 43.427C − 9.5235, with a correlation coefficient of 0.9974 and a detection limit of 0.028 mg/L. Moreover, the effects of foreign substances on the determination of NaCMC were investigated. Based on this, a new method was proposed for the determination of NaCMC in dairy products. This method has been applied to the determination of NaCMC in several dairy product samples with satisfactory results, and the average recoveries were within the range of 86.9 ~ 112.6% with the RSDs below 5.7%.