Hydrogen peroxide solution with concentration of more than 20% weight by weight (w/w) is regulated in Singapore under the Second Schedule of Arms and Explosive Act as it can be utilized as a precursor in homemade explosive devices. Hydrogen peroxide solutions are readily available commercially as antiseptics and in household products such as stain removal products in the concentration range of 2 to 30 % w/w. As such, the qualitative and quantitative analysis of hydrogen peroxide in any exhibit is essential. A workflow was developed using commercial test strips and Raman spectroscopy to screen or identify the presence hydrogen peroxide and titration adapted from ASTM method for the quantitative analysis.
Commercial test strips are simple to use, and minimal sample is required. Three commercial hydrogen peroxide selective test strips were evaluated, and Quantofix Peroxide 100 was chosen due to its wider working range and more accurate colour scale. This test strip can detect hydrogen peroxide solution in the concentration range of 1 to 100 ppm. For hydrogen peroxide solution with concentration higher than 100 ppm, the test strips can still perform as an indicative test for the presence of hydrogen peroxide.
Raman spectroscopy, on the other, is a fast, non-destructive, and reliable analytical technique which can be utilised for the identification of hydrogen peroxide of sharp Raman frequency of 875 cm-1 accompanied by a weak component at 903 cm-1 using 532nm laser. Raman spectroscopy can detect of hydrogen peroxide solution of as low as 0.5% w/w.
The combination of the use of test strips and Raman spectroscopy for the qualitative analysis of hydrogen peroxide reduce the likelihood of false positives. In scenarios where insufficient sample volume is available for titration, the test strips can also be used as a semi-quantitative analysis.
Titration is a simple method with good precision over a wide concentration range. Titration using standardised potassium perma