Selective stopped-flow sequential injection method for the spectrophotometric determination of titanium in dental...

The present work reports the first sequential injection (SI) method for the spectrophotometric determination of Ti(IV). The method is based upon the reaction of Ti(IV) with chromotropic acid (CA) in acidic medium to form a water-soluble complex (lambda(max)=420nm). The chemical and instrumental variables of the system that affected the reaction were studied. Selectivity was greatly enhanced using ascorbic acid. A linear calibration graph was obtained in the range 0.2-10.0mgl(-1) Ti(IV) at a sampling frequency of 24h(-1). The precision was satisfactory (s(r)=1.5% at 5.0mgl(-1) Ti(IV), n=12) and the 3sigma limit of detection, c(L), was 0.7mgl(-1) (n=10). The developed method proved to be adequately selective and was applied successfully to the analysis of real samples (dental implant and natural Moroccan phosphate rock) giving accurate results based on recovery studies (98-105%).