Determination of Ultra-Trace Amounts of Copper in Environmental Water Samples by Dispersive Liquid-Liquid Microextraction Combined with Graphite Furnace Atomic Absorption Spectrometry

A new method of dispersive liquid-liquid microextraction (DLLME) combined with graphite furnace atomic absorption spectrometry (GFAAS) was proposed for the determination ultra-trace copper. It based on reaction Cu(II) laboratory-prepared chelating agent 2-(5-bromo-2-pyridylazo)-5-dimethylaminoaniline (5-Br-PADMA) in a HAc-NaAc buffer solution at pH 5.0 to form stable hydrophobic chelates, which were separated and enriched by DLLME chlorobenzene (C6H5Cl) acetonitrile (CH3CN) as extraction disperser solvents, respectively. The sedimented phase containing chelates then determined GFAAS. Various operating variables that may be affected process such solution, concentration 5-Br-PADMA, types volumes time, centrifugation time investigated. Under optimum conditions, calibration curve linear range from 0.02 ng/mL 0.16 copper correlation coefficient r = 0.9961, detection limit 0.01 3Sb. relative standard deviation six replicate measurements 0.05 ng /mL 3.9%. An enrichment factor (EF) 110 obtained. has advantages low limit, high sensitivity, simple operation, less consumption organic higher factor, environmental friendliness applied trace water samples satisfactory results.