Authors:R. Zwicker, B. Zwicker, S. Laoharojanaphand, and A. Chatt
Neutron activation analysis (NAA) methods were employed for the determination of total arsenic, and water soluble As(III)
and As(V) compounds in freshwater fish/shellfish and plant samples from Southern Thailand. Total arsenic concentrations varied
from 0.05 to 425 mg kg−1. Water soluble arsenic species were separated by solvent extraction using ammonium pyrrolidinedithiocarbamate (APDC)/methylisobutylketone
(MIBK) followed by NAA. The water soluble As(III) and As(V) levels varied from 0.07 to 26.4 and 0.03 to 22.9 mg kg−1, respectively. The As(III) and As(V) detection limits were 0.007 for fish/shellfish, 0.005 for As(III) and 0.006 mg kg−1 for As(V) in plants. This separation method allows for the determination of water soluble As(III) and As(V) using commonly
available and inexpensive laboratory equipment and chemicals, which can be coupled to a variety of quantification techniques.
Tissues, eggs and bile of adult Atlantic cod raised in captivity and fed natural food with no additional halogenated compounds
of any kind were analyzed by neutron activation. There was a large difference in the tissue distributions of extractable organic
chlorine (EOCl) and bromine (EOBr). Liver lipid had the lowest levels of EOBr and EOCl, of all the components investigated,
and eggs had the highest levels of EOCl. Heart contained the most EOBr and EOCl per unit lipid, of the tissues. The presence
of a larger proportion of EOBr than EOCl in bile suggests a higher rate of excretion of EOBr. The EOCl concentratios found
in cod egg lipids were about 5 times higher than the highest values previously reported for EOCl in lipid.
Authors:W. Menendez Sanchez, B. Zwicker, and A. Chatt
A combination of solid phase extraction, coprecipitation, and neutron activation techniques has been used to develop a speciation
analysis method based on green chemistry for the major arsenic species in drinking water. Arsenate as As(V), monomethylarsonic
acid (MMA), and dimethylarsinic acid (DMA) are separated and preconcentrated by strongly anion and cation exchange columns
in tandem while As(III) remains in the effluent. These species are then selectively eluted and As(III) coprecipitated with
bismuth sulphide. This simple method has been applied to the analysis of water reference materials with good results. The
detection limits are 0.9, 1.7, 1.6, 3.8 and 16 ng mL−1 for As(III), As(V), MMA, DMA and total arsenic, respectively, using a neutron flux of 2.5 × 1011 cm−2 s−1 at the Dalhousie University SLOWPOKE-2 reactor (DUSR) facility and anti-coincidence gamma-ray spectrometry.
Authors:B. J. B. Nyarko, E. H. K. Akaho, J. J. Fletcher, B. Zwicker, and A. Chatt
An instrumental neutron activation analysis (INAA) method was developed for the simultaneous determination of 19 elements
in 10 individual food items from Ghana. The samples were irradiated for 1 minutes in a neutron flux of 2.5.