A method of detecting stannous ions that includes providing a zincon-containing indicator having a color, contacting the indicator with a sample, and detecting any resulting change in the color of the indicator, wherein a change in the color of the indicator from the color to colorless indicates that stannous ions are present in the sample. The method is useful for the analysis of oral care compositions. Also provided is the use of zinc on as an indicator for detecting stannous ions.
