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Arsenobetaine and arsenocholine are considered to be non-toxic and are present as a relatively large proportion of total arsenic in seafoods, and they do not respond to hydride generation. The present study describes the effect of seafood consumption on the urinary concentration of hydride-generating arsenic compounds measured by a newly developed flow injection atomic absorption spectrometric (FI-AAS) method. Consumption of plaice, pighvar and tunny resulted in a 2-fold increase, and consumption of mussels produced a 6-fold increase in the urinary level of hydride-generating arsenic compounds. Hence, a person who has consumed mussels may be suspected of being occupationally or environmentally exposed, if the level of consumption of this seafood is unknown. As the FI-AAS method cannot be used to detect arsenobetaine and arsenocholine, the observed increase in urinary concentration of hydride-generating arsenic compounds after consumption of seafood must originate either from hydride-generating arsenic compounds in the seafood or from degraded arsenobetaine or arsenocholine. The present study has demonstrated that both arsenobetaine and arsenocholine are unstable when incubated in daylight in the presence of hydrogen peroxide, i.e., an oxidizing environment. Hence, it is tempting to speculate that arsenobetaine could be converted into hydride-generating arsenic compounds during storage or cooking of seafood. The feasibility of speciation methods based on high-performance liquid chromatographic (HPLC) separation and on-line analysis by inductively coupled plasma atomic emission spectrometry (ICP-AES) and FI-AAS was also investigated. The FI-AAS system is approximately 35 times more sensitive to the hydride-generating arsenic species than the ICP-AES system.(ABSTRACT TRUNCATED AT 250 WORDS)

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Crossed immunoelectrophoresis of human serum spiked with nickel in the range 0.85-24 mmol Ni/L was used to study nickel-protein complexes. These high concentrations, which are far higher than the physiological level (approximately 7.8 nmol/L), were used to saturate both high and low affinity binding sites. Addition of increasing amounts of nickel resulted in dose-dependent changes of the electrophoretic patterns of prealbumin, alpha-1-lipoprotein, alpha-1-antitrypsin and alpha-2-macroglobulin. Radioactive 63Ni was used for crossed immunoelectrophoresis autoradiography experiments for further identification of nickel-protein complexes. When a 63Ni pulse of 740 kBq/application was used, many human serum proteins were labeled. When using a 63Ni pulse of 185 kBq/application only albumin and alpha-1-antitrypsin were visualized clearly. The binding of large amounts of nickel to albumin, visualized by autoradiography, may reflect the high abundance of albumin in human serum as compared to other serum proteins. Addition of nickel to serum proteins resulted in liquid phase precipitation of serum proteins, and rocket immunoelectrophoresis was used to demonstrate that IgG in particular is precipitated. This precipitation of serum proteins may disturb the elution profile when chromatographic techniques are used to analyze nickel-protein complexes. Consequently, immunoelectrophoretic methods may also be attractive alternatives to column chromatographic techniques. The present study demonstrated that, besides the nickel-binding of albumin and alpha-2-macroglobulin, several other serum proteins have nickel-binding affinity.