Adsorptive stripping voltammetric measurements of chromium accumulation in mice organs using mercury film microelectrodes

Chromium is the metallic species of most concern with the use of stainless steel implants. To study the distribution of chromium in mice organs with time, several animals were subcutaneously injected with 2.70 x 10(-3) mol/L of chromium solution during a certain period of time. Square wave voltammetry using adsorptive collection of Cr3+-DTPA complex on a mercury film microelectrode (MFM) was used for quantitation. Optimized conditions included DTPA concentration of 2.0 x 10(-2) mol/L, sodium acetate 4.0 x 10(-2) mol/L, sodium nitrate 0.40 mol/L, potassium permanganate 1.0 x 10(-3) mol/L, pH ca. 6.1, deposition potential of -1.15 V, deposition time 20 s, frequency 100 Hz, step 2.5 mV and an amplitude of 20 mV. The detection limit of the method was 1.54 x 10(-8) mol/L after deposition of 20 s. Other species presented in the biological material such as calcium and iron do not interfere with the chromium determinations. The accuracy of the proposed method was checked by comparing the results with those obtained by atomic absorption spectrometry (AAS) yielding good agreement. The results showed an increase of chromium levels with time in liver, kidney and spleen, indicating that this metal is partially accumulated in the studied organs.