The toxicity and transport mechanisms of mercury and its species in the environment are dependent on the chemical form. Here, the knowledge of the species analysis of organic and inorganic mercury compounds is of interest. Only measuring the total mercury content gives just
a little information about the potential risk to human beings and the health of biota and fish respectively. In comparison methyl mercury is the more toxic species than the inorganic form due to its solubility in lipids and it binds strongly to bio ligands like sulfur containing amino acids bound in proteins. This could affect the functionality of enzymes. A variety of analytical methods have been used for the measurement of mercury species like liquid and gas chromatographic separation and the detection by inductively coupled plasma mass spectrometry and common electron impact mass spectrometry.
Arsenolipids represent a relevant step in the biosynthesis of organoarsenicals from inorganic arsenic compounds. Their fate after human consumption is still uncertain.
By means of a HPLC-ICP-MS/ESI-Q-TOF-MS method, 16 lipid soluble arsenic compounds, including seven formerly unknown organoarsenicals, have been identified in commercial herring fillet.
The structural assignment was done by exact mass and high resolution MS/MS data. This is the first identification of arsenolipids in herring (Clupea harengus). They contribute with (3.6±0.2) mg kg-1 arsenic to 62.3% of the total arsenic content of (5.7±0.3) mg of arsenic per kg dry mass. Current studies indicate that a metabolization by humans to cancerous dimethylarsinic acid is very likely. The presented results are highly relevant as herring is a very popular food fish species in Europe. Moreover, the screening of different fish species revealed that arsenolipids are more widespread than previously assumed.