A method for determining the concentration of coloured compounds in a solution is colorimetry. The intensity of the colour is related to the chemical concentration being measured. Because of their low cost and ability to collect, store, and interpret data all in one device, smartphone-based colorimetry has increased in popularity as an analytical tool. The camera on the phone is used as a detector in smartphone colorimetry. Both the smartphone colorimetric method and the UV method relied on the detection of colour intensity as concentration rose. Distinct oxidation states of ammonium metavanadate generate different colours depending on the oxidation state. The +5-oxidation state appears yellow, the +4-oxidation state appears blue, the +3-oxidation state appears green, and the +2-oxidation state appears purple. The ammonium metavanadate reagent is orange red in colour, but when it combines with pharmaceuticals that contain nitrogen, phosphorus, or sulphur in their structure, it turns green. The developed approach for all of the drugs in this article is linear. The colour intensity increases as the concentration of API increases. All of the photos were captured on a smartphone and analysed with photometrix PRO software. The photometrix PRO application turns an image to an RGB histogram, and it also includes regression models. The percent RSD for all three drugs was less than 2 employing Photometrix PRO and UV method. Using a statistical method called a two-paired test, the results reveal that both procedures are equally significant for all three drugs.
Keywords: Uv spectrophotometry, Photometrix PRO, RGB Histogram, Sumatriptan Succinate, Gemifloxacin, Tenofovir disoproxil fumarate