This Gulf standard is concerned with determination of acidic or basic constituents (Note 1) in petroleum products and lubricants soluble or nearly soluble in mixture of toluene and isopropyl alcohol. It is applicable for the determination of acids or bases whose dissociation constants in water are larger than 10-9; extremely weak acids or bases whose dissociation constants are smaller than 10-9 do not interfere. Salts react if their hydrolysis constants are larger than 10-9 .