| A method for self-control standard sample was discussed to determine petroleum in water. The petroleum standard solution was made from hexadecane, pristine and toluene (1∶1∶1). The obtained result agreed with the certified value when the standard solution was used to determine national standard samples. Two mixed samples prepared by the petroleum standard solution, which concentrations were 20.0 mg/L and 1.00 mg/L separately, were determined for seven consecutive days with water samples to show that relative error of test values ≤7.0% and RSD ranged from 1.3% to 6.7%. |
