A simple and rapid reverse phase HPLC method has been developed for th
e determination of adulteration in petrol (gasoline) with Kerosene. Me
thanolic solutions of petrol, Kerosene and their synthetic admixtures
were analysed on HPLC using C-18 ODS column and Acetonitrile : Water (
8:2) as mobile phase, a the flow rate of 1 ml/min and UV-absorption de
tection at 285 nm. The UV detector at 285 nm gives specificity to dete
ction, since the alkyl naphthalenes predominantly present in kerosene
have strong, characteristic absorption around 285 nm. The amplitudes o
f the peaks corresponding to these naphthalenes (C-10 - C-12) increase
d with the added quantum of kerosene linearly. Average values with +/-
SD of intrachromatographic ratios generated for the peak heights of t
he naphthalenes Sigma(C-10 to C-12) divided by peak height of solvent
methanol were tabulated. These ratios could be used to get a linear cu
rve if evaluated graphically against corresponding (P:K) composition f
or determining extent of adulteration with kerosene, even down to a le
vel of 5% v/v in suspected petrol samples.