The Electroanalytical Determination of Sodium Borohydride Using a Gold Electrode

Sodium borohydride or sodium tetrahydroborate is used as a reducing agent in many organic and inorganic reactions. Therefore, the determination of sodium borohydride present in the system is of great importance. Borohydride releases hydrogen under appropriated conditions in the presence of a suitable catalyst. Since the amount of hydrogen emitted is proportional to the amount of borohydride, the measurement of the amount hydrogen emitted was the first method used for the determination of the borohydride present in the system. This method is also employed in studies searching for suitable electrocatalysis for hydrogen generation from borohydride under different conditions2−3. Apart from the measurements of the hydrogen emitted, the amount of borohydride present in the system can conveniently be determined by the use of titrimetric methods. The most popular technique among these is the iodide method. In this method excess IO3 is added to the medium and the remaining IO − 3 after the reaction with BH − 4 is back titrated with buffered S2O 3 . The semiquantitative silver-ethylenediamine (Ag-EDDA) is based upon the reaction of Ag (I) with BH4 in 4% EDA solution in 50% NaOH . Crystal violet methods are particularly suitable in nonaqueous media . The reduction of phosphotungstate can be conveniently used as a spot test for the determination of the presence of BH4 in the medium . In addition to all these, although not used in the literature very commonly, it was determined that the addition of 0.1-0.05 M strongly basic solution of NaBH4 to KMnO4 results in the disappearance of the pink color of the solution. This method can be used ∗Corresponding author