Separation and preconcentration of inorganic arsenic species in natural water samples with 3-(2-aminoethylamino) propyltrimethoxysilane modified ordered mesoporous silica micro-column and their determination by inductively coupled plasma optical emission spectrometry

Evaluation of the fate of arsenic-contaminated groundwater at different aquifers of Thar coalfield Pakistan

“…The As species are unstable in natural waters because of the transformation between As 3+ and As 5+ due to the organic matrices, redox potential, and pH Chen et al 2009;Thirunavukkarasu et al 2002;Wang and Mulligan 2006). Under oxidizing conditions, As 5+ (H 2 AsO 4− ) is dominant at low pH (pH <6.9), whilst at higher pH, HAsO 4 2− becomes dominant (H 3 AsO 4 and AsO 4 3− may be present in extremely acidic and alkaline conditions, respectively).…”

Speciation of ultra-trace amounts of inorganic arsenic in water and rice samples by electrothermal atomic absorption spectrometry after solid-phase extraction with modified Fe3O4nanoparticles

“…Different adsorption behaviours of the two ions can be explained by their different ionic characters. According to the pK a values of As(V) (2.3 and 6.8) and As (III) (9.2), As(V) ions exist dominantly in oxoanionic forms (H 2 AsO 4 − and HAsO 4 2− ) while As (III) is in neutral form (HAsO 2 ) [10] in pH range of 2-6. In modified magnetic adsorbent, amine groups of APTS (pK a = 10.3) [32] were in protonated form at pH < 9 which favour the adsorption of negatively charged As(V) species.…”

“…For example, average level of this element in open seawater is typically around 1.5 µg L −1 and show little variation or its typical concentration in freshwater is less than 10 µg L −1 [9]. So, the World Health Organization (WHO) has reduced daily intake of As in drinking water from 50 to 10 µg L −1 [10]. On the other hand, organic As such as monomethylarsenic acid, dimethylarsenic acid and arsenobetaine which are metabolites of inorganic As mainly occur in marine and other biological samples [11].…”

Selective recovery of indium from the etching waste solution of the flat-panel display fabrication process

“…A high enrichment factor from the SPE process is obvious if the eluent possesses the capacity to elute the species with a minimum volume without affecting its precise analysis [42].…”