Laser induced breakdown spectroscopy (LIBS) is applied to analyze aqueous solutions of Li+, Na+, Ca2+, Ba2+, Pb2+, Cd2+, Hg2+ and Er3+ and suspensions of ErBa2Cu3Ox particles (d = 0.2 μm). An excimer (308 nm) pumped dye laser with laser pulse at 500 nm and pulse energy at 22 ±2 mJ is used to produce plasma in aqueous solution. Plasma emission lines of the elements are detected by a photodiode array detector. Detection limits of the metal ions are 500 mg/l for Cd2+, 12.5 mg/l for Pb2+, 6.8 mg/l for Ba2+, 0.13 mg/l for Ca2+, 13 μg/l for Li+ and 7.5 μg/l for Na+. No mercury and erbium emission can be detected, even at Hg2+ and Er3+ concentrations of up to the g/l range. On the other side, for Er in suspensions of ErBa2Cu3Ox particles a more than 103 times higher sensitivity is found than for dissolved Er3+. This result gives a possibility to analyze colloid-borne metal ions with an increased sensitivity.