Efficient lead preconcentration using two chemically functionalized carbon nanotubes in hyphenated flow injection-flame atomic absorption spectrometry system

•Highly sensitive and rapid Pb detection on modified nanomaterials in water samples.•Simultaneous preconcentration-determination by hyphenated flow injection-FAAS.•The nanomaterials were stable and reusable for ~350 cycles.•High sampling rate (~30 h−1) with excellent RSD (~1%) and accuracy (> 95%) values.•The recovery of Pb from contaminated water samples was > 95%.