Due to insufficient Chemical Petroleum additives instead of using ether. As a result, the values are negative values light suck because chlorophyll is soluble in petroleum.
Since the chemical is not enough So instead of using petroleum ether As a result, the absorbance is negative because chlorophyll is soluble in petroleum.
Because of chemical is not enough. Petroleum is used instead of the ether. Light absorption value resulting in negative due to the chlorophyll insoluble in petroleum.