In recent years, great advances have been observed in the proteomic area regarding the different approaches adopted as top-down, middle-down and bottom-up. Regarding middle-down and bottom-up approaches, a previous step for protein digestion is necessary for further analysis of the generated peptides. Classical digestion protocols employing proteases are usually carried out in solution, which can lead to a number of disadvantages such as high digestion time, enzymatic autolysis and impossibility to reuse the enzymes. In view of these drawbacks, different approaches have been studied and applied for improving enzymatic efficiency, inhibition of autolysis, reduction of digestion time, and to minimize the number of missed cleavages. In the literature, great efforts have been made in order to achieve maximum efficiency in enzymatic digestion, with emphasis on proteases immobilization. In this review, concepts related to protein digestion, immobilization techniques, as well as the main support used for enzyme immobilization are discussed considering new tools for proteomic analysis. years topdown, topdown top down, down top-down middledown middle bottomup. bottomup bottom up. up peptides solution time enzymes drawbacks cleavages literature review techniques

Identifying impurities in drug substances has become one of the most important issues in pharmaceutical analysis since it can have a significant impact on the efficacy of new pharmaceutical products. Due to the purity requirements, in this paper a new synthetic α2-adrenoceptor agonist, called LPSF-PT-31, was purified and its impurities were characterized by liquid chromatography-multistage mass spectrometry (LC-MSn) and liquid chromatography-solid phase extraction-nuclear magnetic resonance (LC-SPE-NMR). The purification step was conducted using a semi-preparative liquid chromatography and stacked injections as a new approach to drug purification. As a result, a total yield of 75% of the pure LPSF-PT-31 and 2.9 L day-1 in solvent reduction was obtained. The combination of semi-preparative stacking injection, LC-MSn, and LC-SPE-NMR, demonstrated to be efficient to purify active drugs and unambiguously identify its impurities. In addition, isolation and identification of drug impurities in the early stages of development can improve the synthetic pathway, preventing the formation of impurities or minimizing this formation to minimum levels.

Descreve-se o desenvolvimento e validação de um método de CLAE para acompanhar a degradação de fenol por tratamento eletroquímico ou fotoeletroquímico. Este método, que permite a determinação das quantidades de fenol, p-benzoquinona e catecol em soluções eletrolisadas ou fotoeletrolisadas, foi usado para análise dos intermediários de reação durante a eletroxidação ou fotoeletroxidação de fenol. Foram usados como eletrodos, Ti-Pt/PbO2 (obtido por método térmico-eletroquímico ou por eletrodeposição) ou Ti/TiO2 dopado com Ga3+ (obtido por decomposição térmica de sais precursores).

The development and validation of a HPLC method to follow the degradation of phenol by electrochemical or photoelectrochemical treatment are described. This method, which allows determining amounts of phenol, p-benzoquinone and cathecol in electrolyzed or photoelectrolyzed solutions, was used for analysis of reaction intermediates during electrooxidation or photoelectrooxidation of phenol using a Ti-Pt/PbO2 (obtained by thermal-electrochemical or electrodeposition methods) or Ti/TiO2 doped with Ga3+ (obtained by thermal decomposition of precursor salts) electrode.