Highly sensitive determination of Cu(II) ions in hemodialysis water by F AAS after disposable pipette extraction (DPX) using Moringa oleifera as solid phase

Abstract Clinical samples, such as hemodialysis water, require constant monitoring, since inappropriate processing can lead to copper intoxication even at low concentrations. Sensitive, inexpensive and environmental friendly sample preparation procedures are desirable. For this proposal, an extraction and preconcentration procedure by Disposable Pipette Extraction (DPX) was developed using an homemade device with Moringa oleifera seeds powder as a solid phase for the determination of Cu(II) ions in hemodialysis water at levels of µg L-1 by flame atomic absorption spectrometry (F AAS). The proposed DPX device consists of a conventional micropipette tip, syringe, adapter and glass wool as a filter, being easy to operate, simple and low cost. The optimized extraction and preconcentration conditions allowed the use of 10 mg solid phase with particle size of 250 µm, 6 extraction cycles of sample aliquots at pH 6 and elution with 0.5 mol L-1 hydrochloric acid solution (250 µL). The working concentration range showed satisfactory linearity between 10 - 100 µg L-1 (r2 = 0.9992), assessed by the Mandel test (DS2/Sy22