Introduction: Shodhana (purification) of metals and minerals is a most important step before preparing their bhasma (incinerated powder). Shodhana treatment removes the soluble, evaporable and washable impurities from metal/mineral and also adds some organic materials which from chemical point of view may be considered as impurities but pharmacological point of view prove beneficial by reducing their toxicity to the great extent. There is need to develop some standard parameters to ensure proper shodhana. This can be achieved by developing standard operating procedure (SOPs) for every step of shodhana. Thus an attempt has been made to introduce SOPs for Naga shodhana.
Aim: To develop SOP for Naga shodhana, to study the physic-chemical changes in the media used for shodhana and assess the chemical change in shodhita Naga.
Method: Naga Samanya and Vishesha shodhana was done according to the reference of Sharangadhara samhita and Rasatarangini respectively. Physico-chemical analysis of shodhana media was done before quenching and after quenching of melted Naga. Analysis of ashuddha Naga (raw lead) and Vishesh shodhit Naga was done by purity testing, FTIR (Fourier Transform Infrared Spectrometry) and TGA (Thermogravimetric Analysis).
Result and conclusion: Ashuddha Naga was 99.80 % pure whereas Shodhita Naga was 99.40 % pure. pH, Specific gravity and total solid content of each media was increased after quenching of melted Naga. Up to complete shodhana average loss occurred was 6.26 %. Melting point of Naga slightly increased from 327.46 0C to 328.42 0C. FTIR analysis of ashuddha Naga showed sharp peaks indicating stretching vibrations between various inorganic molecules while in shodhita Naga stretching vibrations between C-H and C-N were observed which are assigned to presence of alkyl compounds specifically methyl bond. The report of TGA shows the presence of non-volatile organic compounds in the shodhita Naga due to repeated quenching in different media.
Key words: Naga shodhana, Standard operating procedure, TGA, FTIR