Certipur icp multi element standard solution 4

All reagents used were of analytical-reagent grade and all aqueous solutions were prepared with MilliQ water (MilliporeCorp., Milford, MA, USA). The stock standard solutions were CertiPUR^® ICP Multi-element Standard Solution IV (23 elements in diluted nitric acid), Merck Millipore, 1000 mg/L; and CertiPUR^® Reference material GF AAS Multi Element Standard Solution XVIII, Merck Millipore, 100 mg/L. The working standard solutions were prepared weekly through appropriate dilutions. Concentrated HNO₃ (65%, Suprapur, Merck, Kenilworth, NJ, USA) was used for the wet digestion of honey.

The metal concentration in the analyzed solutions was determined via ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry) (Agilent 725 Series ICP Optical Emission Spectrometer, Agilent Technologies Inc., United Sates). A TraceCERT^® Rare earth element mix for ICP with 16 elements from Sigma-Aldrich (Sigma-Aldrich, Taufkirchen, Germany) and a Certipur^® ICP multi-element standard solution IV from Merck (Merck KGaA, Darmstadt, Germany) with 23 elements, were used as standards for calibration. Data analysis was done with ICP Expert II Agilent 725-ES Instrument Software Version 2.0 (Agilent Technologies Inc., United Sates).