Prussian blue insoluble 500mg capsules

Films of Prussian Blue (PB) deposited by electroreduction in the absence of K + have absorbance maxima at 730 nm which narrow and shift on voltammetric cycling in KCI solution to 690 nm, these absorptions being deemed diagnostic of 'insoluble' and 'soluble' PB respectively. Spectroelectro- chemistry shows that the initial deposit even in K+ solution is invariably the insoluble form, being then converted into the soluble, irrespective of electrochemical conditions or solution composition ; this resolves several problems in the current literature. Electrochemical oxidation of PB gives continuous mixed-valence compositions up to complete oxidation ; by contrast, reduction to Prussian White involves clean conversion of one into the other at a critical potential.

Abstract licence: CC BY-NC-ND

Perls’ Prussian blue staining or reaction is used to detect haemosiderin, which is stored or sequestrated non-haeme iron. Methodologically, the iron in haemosiderin is released as Fe 3+ (Fe III ) by hydrochloric acid (HCl), and Fe III reacts with potassium ferrocyanide (K 4 [Fe II (CN) 6 ]) to form Prussian blue. Iron released from ferritin, another stored non-haeme iron, is too scarce to be detected. Haeme iron, including haemoglobin and cytochromes, is not released by HCl. Thus, haemosiderin can easily be detected under the microscope as distinct blue deposits with minimal background staining. The chemistry of cyanide-bridged iron complexes, including Prussian blue and Turnbull blue, is the basis for understanding Perls' staining. Prussian blue is a cubic lattice with Fe II or Fe III ions alternately aligned at the corners to give Fe II –CN–Fe III formations at the edges. Physicochemically, Prussian blue is soluble in water (dispersible as a colloid) or insoluble depending on how it is formed. As with Perls' staining, Prussian blue is expected to take a soluble form because of excess K 4 [Fe II (CN) 6 ] compared to Fe 3+ released from tissues. Notably, Prussian blue used in Perls' staining does not in fact dissipate into the staining solution but remains on the tissue, rendering this a practical method for histological detection of haemosiderin and also exogenous iron of forensic significance. However, further examinations of its mechanisms are needed to evaluate the applicability of this method on various forensics cases.

Abstract licence: CC BY