Influence of oxidising agents in lead determination by hydride generation direct flame atomic absorption spectroscopy

Determination of lead in wine and rum samples by flow injection-hydride generation-atomic absorption spectrometry

“…Sodium borohydride solution (NaBH 4 , 0.2%, m/v) was freshly prepared daily by dissolving the appropriate amount of NaBH 4 (98% pure, Alfa) in 0.05% (m/v) sodium hydroxide solution. Potassium ferricyanide solution (3%, m/v) was prepared freshly by dissolving the appropriate amount of K 3 Fe(CN) 6 (Aldrich) in 0.03% (v/v) HCl solution (Fisher Scientific).…”

“…Solutions of K 3 Fe(CN) 6 (3% m/v) and NaBH 4 (0.2% m/v) used in these experiments were prepared in 0.03% (v/v) HCl and 0.05% (m/v) NaOH, respectively.…”

“…Generation of lead hydride depends largely on the experimental conditions used, therefore, previous studies have mainly focused on the nature of the acids and oxidizing agents, and their roles in the generation of plumbane. Most common oxidizing agents used in presence of various acids include hydrogen peroxide [6][7][8][9], ammonium or sodium peroxodisulphate [6,10,11], potassium dichromate [6,8,11] and potassium ferricyanide [11,12]. Depending on the type of oxidizing agent, it was reported that the use of acidic oxidizing media increased the reaction rate and sensitivity via efficient oxidation of Pb(II) to an unstable intermediate, Pb(IV), to form plumbane, PbH 4 , [5,6,13,14].…”

“…Most common oxidizing agents used in presence of various acids include hydrogen peroxide [6][7][8][9], ammonium or sodium peroxodisulphate [6,10,11], potassium dichromate [6,8,11] and potassium ferricyanide [11,12]. Depending on the type of oxidizing agent, it was reported that the use of acidic oxidizing media increased the reaction rate and sensitivity via efficient oxidation of Pb(II) to an unstable intermediate, Pb(IV), to form plumbane, PbH 4 , [5,6,13,14]. Better sensitivity was reported by using potassium ferricyanide, K 3 Fe(CN) 6 ), a relatively mild oxidant [15][16][17][18][19][20].…”

“…Depending on the type of oxidizing agent, it was reported that the use of acidic oxidizing media increased the reaction rate and sensitivity via efficient oxidation of Pb(II) to an unstable intermediate, Pb(IV), to form plumbane, PbH 4 , [5,6,13,14]. Better sensitivity was reported by using potassium ferricyanide, K 3 Fe(CN) 6 ), a relatively mild oxidant [15][16][17][18][19][20]. Lead hydride generation with a mixture of potassium ferricyanide and hydrochloric or nitric acid has been successfully applied to the determination of Pb in various samples, including soil and sediments [18,19], calcium matrices [20,21], urine [17], dialysis concentrates [15], geochemical deposits and paint [22].…”