Characterization of toothpastes for fluorine and other elements by INAA and ICP-OES

Fluoride toothpastes have made a significant contribution towards oral hygiene. This study proposes instrumental neutron activation analysis (INAA) as a suitable technique for determining fluorine in toothpastes. The method involved a 10 s irradiation, followed by 10-20 s decay, and counting for 10 s, using a pneumatic system and high purity germanium detector. All irradiations were performed at miniature neutron source reactor with thermal neutron flux 1 x 10(12) cm(-2) s(-1). Since Na was present in all toothpastes, the quantification of fluorine required correction for Na-23(n,alpha)F-20 threshold reaction. Fluorine determination was validated by analysing the samples by ion chromatography. All toothpastes were also analysed for other elements by k(0)-INAA and ICP-OES. Both techniques quantified 28 elements including Al, As, Ba, Ca, Ce, Cl, Co, Cr, Cu, F, Fe, Hf, K, La, Mg, Mn, Na, P, S, Sb, Sc, Si, Sm, Sn, Sr, Ta, Ti and Zn. This study, categorized toothpastes in five groups based on concentrations of Ca, P and Ti.