Technique for determining nickel in blood by flameless atomic absorption spectrophotometry

We describe a technique for determining nickel in serum by flameless atomic absorption, with use of dimethylglyoxime. The procedure permits a greater number of analyses per technician at a relatively low cost, yet provides acceptable accuracy and reliability. After the sample is evaporated and dry ashed in a muffle furnace at 560 degrees C for 5 h, the residual salts are dissolved in hydrochloric acid (1 mol/liter). Sodium citrate and dimethylglyoxime are then added for complexation of iron and nickel, respectively. The pH is adjusted to 9 with ammonia and the nickel dimethylglyoxime is extracted with methyl isobutyl ketone. The determination is carried out by injecting 50 mul of the organic phase into the graphite furnace, where the sample is dried at 120 degrees C and ashed at 1200 degrees C, respectively.