Copper fractionation with dissolved organic matter in natural waters and wastewater—a mixed micelle mediated methodology (cloud point extraction) employing flame atomic absorption spectrometry

Abstract

A cloud point extraction-preconcentration methodology for the speciation analysis of free and organically complexed metal species in natural waters is presented. The method is based on the neutralization of the electrostatic charge of the humate-metal complexes with a positively charged surfactant in a high ionic strength solution environment. The resulting complexes are conveniently solubilized in the micelles of a non-ionic surfactant medium and are thus separated from the bulk aqueous phase. Free metal species are also determined by complexation with a conventional chelating agent under mild conditions. The overall procedure is easy, rapid and allows for a high sample throughput in terms of massive analysis of many samples in the same time period. The method offers substantially low detection limits of 8.5 and 0.9 micrograms l-1 for bound and labile species respectively, with a calibration curve rectilinear in the wide range 40-150 micrograms l-1 for the humate associated and 4-40 micrograms l-1 for the free metal species. The method is free from interferences yielding recoveries in the range 97-102% for various samples of different matrixes.

Investigation of cloud point extraction for the analysis of metallic nanoparticles in a soil matrix

“…56 Therefore, factors such as decrease of repulsive interactions (at higher ionic strength) and protonation of HA to the neutral molecular form (at acidic pH) in the water/surfactant media may enhance the interaction of HA-coated AuNPs with the micellar aggregates and thus improve extraction efficiency. 55, 57 Similarly, in the present study, the recovery of PVP-coated AuNPs is less than 20 % when TX-114 alone is used for extraction. Recovery for the HA treated AuNPs is improved by the addition of NaCl, CA and EDTA (see visual observation, Figure S5).…”

Répartition des paramètres physico-chimiques et métalliques des eaux usées de Hann (Dakar) avec le milieu marin

“…Dans ce milieu, tous les polluants, particulièrement les métaux lourds sont soumis au même titre que les substances naturelles, au jeu des phénomènes biogéochimiques (Maurice, 1996). Ces éléments peuvent se retrouver dans l'eau, à l'état de complexes minéraux ou organiques, sous forme colloïdales ou particulaires et se répartissent donc dans le milieu aquatique (Kunz et Jardim, 2000 ;Giokas et al, 2002). Les eaux usées urbaines constituent l'une des principales voies des métaux vers les écosystèmes aquatiques (Buzier et al, 2006).…”

Atomic spectrometry update. Industrial analysis: metals, chemicals and advanced materials

“…A cloud point method for the FAAS determination of free and organically complexed Cu species in natural waters has been presented. 114 The method was based on the neutralization of the electrostatic charge of the humate-metal complexes using a positively charged surfactant. The resulting complexes were then dissolved in the micelles of a non-ionic surfactant and were thus separated from the bulk aqueous phase.…”