Potassium chloride (KCl), sodium carbonate (Na2CO3), and sodium bicarbonate (NaHCO3) were supplied by Chempur. Hydrochloric acid (HCl) was purchased from Stanlab Lublin, Poland, isopropanol from Linegal Chemicals, Poland, and compressed argon was supplied by Air Liquide, France. A glass micropipette column filled with aluminum oxide (Al2O3) for chromatographic adsorption analysis acc. to Brockman (II), Budapest, Hungary, was used for pyrrole purification. Honey used for real sample analysis was purchased on open market from Polish producer. All chemicals and solvents were of analytical grade. All aqueous solutions were prepared using distilled water.