An azo compound which is reduced in the copper ion content and exhibits hue and clarity suitable for ink-jet recording and which can give records having excellent light fastness, water resistance, and moisture proofness, and such ozone resistance as to control the fading and the discoloration; and water-base yellow inks containing the same. In particular, the azo compound represented by the formula (12) having a content of impurity copper ions of 100 ppm or below or salts thereof, and inks containing the same ##STR00001##