10.1016/j.electacta.2013.09.101
Nano-perovskite carbon paste composite electrode for the simultaneous determination of dopamine, ascorbic acid and uric acid

All chemicals were used as received without further purification. Ammonium hexachloropalladate (IV) (Aldrich, 99.99%), strontium nitrate, citric acid, glycine, urea, nitric acid, ammonium hydroxide (Aldrich), graphite powder (Sigma-Aldrich, <20 μm, synthetic) and Paraffin oil (Fluka) were used as received without further purification. Dopamine (DA), uric acid (UA), ascorbic acid (AA) and potassium ferricyanide were supplied by Aldrich Chem. Co. (Milwaukee, WI. Aqueous solutions were prepared using double distilled water. Phosphate buffer solution PBS (1 mol L-1 K2HPO4 and 1 mol L-1 KH2PO4) of pH 2-11 was used as the supporting electrolyte. pH was adjusted using 0.1 mol L-1 H3PO4 and 0.1 mol L-1 KOH. 

Stoichiometric amounts of (NH4)2PdCl6 and Sr(NO3)2 were weighed, dissolved in distilled water, then a sufficient amount of certain fuel (citric acid, glycine, or urea) was added. The pH of the solution was adjusted to certain value (2, 7, or 10) by nitric acid and ammonium hydroxide. The solution was heated on a hot plate to about 250 degC. The precursor complex undergoes dehydration to produce foam which then ignited giving a voluminous black fluffy powder.
Ammonium hexachloropalladate (IV)
99.99%
%
graphite powder
<20 μm
μm
Phosphate buffer solution PBS
K2HPO4
1 mol L-1
mol L-1
Phosphate buffer solution PBS
pH
2-11
Phosphate buffer solution PBS
KH2PO4
1 mol L-1
mol L-1
H3PO4
0.1 mol L-1
mol L-1
KOH
0.1 mol L-1
mol L-1
solution
pH
2, 7, or 10
solution
heated
about 250 degC
degC