Determination of cadmium in cosmetics from Kermanshah, Iran by graphite furnace atomic absorption spectrometry

Abstract

Continuous sample drop flow-based microextraction (CSDF-ME) combined with graphite furnace atomic absorption spectrometry (GFAAS) has been developed as a high-performance preconcentration technique for the determination of cadmium in cosmetic samples. In this method, a few microliters of an organic solvent, e.g. 37.0 µL of carbon tetrachloride, is transferred to the bottom of a conical sample cup. Then, 10.0 mL of an aqueous solution added via a syringe needle becomes transformed into fine droplets as it passes through the organic solvent. As a result, a cadmium-ligand hydrophobic complex is extracted into the organic solvent. After extraction, the conical sample cup is transferred to the GFAAS instrument, and 20 µL of the extraction solvent is then injected into the graphite furnace using an autosampler. Under the optimum conditions, the calibration curve was linear in the range of 0.005–0.05 µg kg⁻¹, with a detection limit of 0.002 µg kg⁻¹. The extraction recovery and enrichment factor were 58.7% and 234, respectively. The repeatability (intra-day) and reproducibility (inter-day) of the method based on seven replicate measurements of 20 ng L⁻¹ of cadmium were 3.2% and 4.5%, respectively. Consequently, the developed method was successfully applied for the extraction and determination of cadmium ions in lipsticks, eye shadows, and hair dyes, with satisfactory results.