Retention of arsenate using genetically modified coryneform bacteria and determination of arsenic in solid samples by ICP-MS.
A novel method for the retention of arsenate [As(V)] combining time-controlled solid-phase extraction with living bacterial biomass is presented. As(V) retention was carried out by exposing the extractant, consisting of a living double-mutant of Corynebacterium glutamicum strain ArsC1-C2, to the sample for a retention time of 1-7min, before the arsenic distribution equilibrium between the sample solution and the extractant was established. The amount of As(V) retained in the biomass was measured by inductively coupled plasma-mass spectrometry (ICP-MS) after the sample had been treated with nitric acid. A theoretical model of the retention process was developed to describe the experimental retention-time profiles obtained with the bacterial cells. This relationship provided a feasible quantification of the retention process before steady-state was reached, providing that the agitation conditions and the retention time had been controlled. An analytical procedure for the retention/quantification of As(V) was then developed; the detection limit was 0.1 ng As(V)mL(-1) and the relative standard deviation 2.4-3.0%. The maximum effective retention capacity for As(V) was about 12.5mgAs(g biomass)(-1). The developed procedure was applied to the determination of total arsenic in coal fly ash, using a sample that had undergone oxidative pre-treatment.
Villadangos
A F
AF
Department of Molecular Biology, Area of Microbiology, University of León, E-24071 León, Spain.
Ordóñez
E
E
Muñoz
M I
MI
Pastrana
I M
IM
Fiuza
M
M
Gil
J A
JA
Mateos
L M
LM
Aller
A J
AJ
D053502:Arsenate Reductases / Q000235:genetics; D001149:Arsenates / Q000302:isolation & purification / Q000378:metabolism*; D001151:Arsenic / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism; D018533:Biomass; D048230:Corynebacterium glutamicum / Q000235:genetics* / Q000378:metabolism*; D004785:Environmental Pollutants / Q000032:analysis*; D007700:Kinetics; D013058:Mass Spectrometry; D008954:Models, Biological; D009154:Mutation; D030781:Organisms, Genetically Modified; D052616:Solid Phase Extraction; D013997:Time Factors
D001149:Arsenates; D004785:Environmental Pollutants; D053502:Arsenate Reductases; D001151:Arsenic; C025657:arsenic acid