A new, simple, rapid, sensitive and environmentally friendly ultrasound-assisted emulsification dispersive liquid-liquid microextraction (UAE-DLLME) has been developed for trace nickel Ni(II) separation and preconcentration in environmental samples prior to spectrophotometric determination.The proposed method based on using non-ionic water-soluble surfactant Triton X-114 (TX-114) as a disperser so...