This study aims to investigate the colour spectrum of premium motor spirit sold in dispensing stations around Sapele metropolis in comparison with the color scale (comparator) for petroleum products and to ascertain if PMS quality is determined by colour hue in relation to octane rating. Also known as petrol or gasoline, premium motor spirit (PMS) is a mixture of branched-chain aliphatic alongside a small proportion of aromatic hydrocarbons. The petroleum product samples were obtained from different petrol dispensing stations around Sapele metropolis from 1st to 31st April, 2023. To assess the color of petroleum products, international standards like ASTM D1500 and ASTM 156 (Saybolt) scales were used for quality control tests. A clean beaker of about 500-ml was properly washed and rinsed, thereafter light source (white fluorescent light or LED bulb) was prepared. 100 ml of sample was weighed into the beaker with the aid of a measuring cylinder, afterwards colour of sample was tallied with the color scale (comparator) for petroleum products. Colour unit 0.5 (pale straw) had frequency of five samples, which represents 25%. Fuel stations such as Obryan, Nipco, Hydropet, A-Gene-Ezes, and Akpojevughe had colour hues of ?pale straw? with unit 0.5, while Premium, Baseyom, Kay J, Gaye, Rainoil Olympia, and Rainoil Ajogodo had unit 1.5 colour hue ?pale gold?, which was the highest unit representation at 30%. This research found that PMS products sold within Sapele metropolis fell within a range of 0.5 (pale straw) to 3.0 (medium amber) and could be regarded as “good oil’ with a fairly high level of purity.

Keywords: Premium motor spirit (PMS), ASTM D1500, colour, fuel, octane rating.