Reagents
3. The following reagents shall be used–
(a)concentrated sulphuric acid solution;
(b)silicone-based anti-foaming emulsion;
(c)cyclohexane (analytical reagent grade);
(d)hexane (analytical reagent grade);
(e)ethanol (analytical reagent grade);
(f)anhydrous sodium sulphate;
(g)silica gel GF 254 (Merck or equivalent);
(h)standard 1 per centum (weight/volume) solution of pure biphenyl in cyclohexane: dilute with cyclohexane to obtain the following three solutions–
(i)0.6 μg/μl;
(ii)1 μg/μl;
(iii)1.4 μg/μl.