Determination of vanadium in urine by electrothermal atomic absorption spectrometry using hot injection and preconcentration into the graphite tube

in this work it was developed a procedure for the determination of vanadium in urine samples by electrothermal atomic absorption spectrometry using successive injections for preconcentration into a preheated graphite tube. three 60 μl volumes were sequentially injected into the atomizer preheated to a temperature of 110 oc. drying and pyrolysis steps were carried out after each injection. a chemical modifier, barium difluoride (100 mg l-1), and a surfactant, triton x-100 (0.3% v v-1), were added to the urine sample. when injecting into a hot graphite tube, the sample flow-rate was 0.5 μl s-1. the limits of detection and quantification were 0.54 and 1.82 without preconcentration, and 0.11 and 0.37 μg l-1 with preconcentration, respectively. the accuracy of the procedure was evaluated by an addition-recovery experiment employing urine samples. recoveries varied from 96.0 to 103% for additions ranging from 0.8 to 3.5 μg l-1 v. the developed procedure allows the determination of vanadium in urine without any sample pretreatment and with minimal dilution of the sample.