Toxic metal salt

The corrosive effects to be considered (mainly simple corrosion of metals) are, as would be expected from the edible nature of foodstuffs which are not excessively either acidic or basic but which may contain sulphur, less severe than those often encountered with inedible materials containing reactive substances. The importance of corrosive efiects where foodstuffs are concerned lies not so much in the action of the foodstuffs on the metal involved as in the resultant metal contamination of the foodstuff itself, which may give rise to off-flavours, in the acceleration of other undesirable changes (by the Maillard reaction for example), and in the possible formation of toxic metallic salts. Metal ions generally have threshold values of content for incipient taste effect in different liquid foodstuffs. Except in the case of the manufacture of fruit juices and pickles, process plant failure through corrosion must be rare. Nevertheless all foodstuffs, particularly liquid ones, should be regarded as potentially corrosive and capable of metal pick-up which may be undesirable. 

The protection-deprotection reaction sequences constitute an integral part of organic syntheses such as the preparation of monomers, fine chemicals, and reaction intermediates or precursors for pharmaceuticals. These reactions often involve the use of acidic, basic or hazardous reagents and toxic metal salts [30], The solvent-free MW-accelerated protection/deprotection of functional groups, developed during the last decade, provides an attractive alternative to the conventional cleavage reactions. 

If one does not fully understand the theory and practice of metal works, an assumed "Tincture of Iron or Copper" may just be a solution of toxic metal salts and not the true alchemical Sulfur of the metal. Many operators consider the metal as a catalyst which acts upon the solvent to change it in characteristic ways. The actual metal is not present in the final product. 

While the use of sugar of lead as a sweetener died out after the fall of the Roman Empire, the use of lead salts in food did not. Much more recently, for example, lead chromate, or chrome yellow , has been used to colour sweets and custard powder. As recently as the nineteenth century toxic metal salts were used as food colourants, for example the dye Scheele s green was used to colour blancmanges green. This dye is copper arsenite, containing both copper and, more importantly, arsenic. 

To circumvent these issues, a relatively non-toxic metal salt was chosen as starting material along with a set of non-toxic ligands iron(III) nitrate and the ligands oxalate and citrate (Figure 2). 

Other so-called gold substances produced by alchemists were often toxic metal salts that happened to have a yellow sheen such as lead antimonate (PbSb205) and metallic mercury (Hg) salts " ... 

Stress Fingerprint Induced by a Herbicide, 2,4-D, and two toxic metal salts... 

---