The Commissioner of Agriculture is required to appoint, in accordance with Chapter 20 of Title 45, a chemist, who shall be an expert oil analyst, to be designated as the state oil chemist, whose duty it shall be to analyze all samples of gasoline and kerosene and all fluids purporting to be substitutes therefor or motor fuel improvements or other like products of petroleum, under whatever name they may be designated, and used for illuminating, heating, cooking, power, or lubricating purposes, submitted by the Commissioner of Agriculture or any duly authorized inspector or inspectors.