Background: Erythropoietin, as a principal hormone promotes red blood cell production in bone marrow. Varieties of erythropoietin biosimilar are being produced by recombinant DNA technology in cell cultures. The detection or quantification of these molecules are being performed by diff erent methods which some of theme such as Western blot and enzymelinked immunosorbent assay (ELISA) require sp...

The effects of an on-line ion suppressor device on alkali metal ion adduct formations of the model compound tacrolimus were investigated. The base peak ion in the positive ion ESI-MS spectrum of tacrolimus was a sodium ion adduct, [M+Na](+). On the other hand, an ammonium ion adduct, [M+NH(4)](+), was the base peak ion in the full-scan mass spectrum of tacrolimus with a cation-exchange suppress...

Ammonia in water is either unionized ammonia (NH3) or the ammonium ion (NH4). The techniques used to measure ammonia provide a value that is the sum of both forms. The value is reported as “total ammonia” or simply “ammonia.” (In this publication, “ammonia” refers to the sum of both forms; the specific forms will be referred to as appropriate.) The relative proportion of the two forms present i...

a rapid isocratic method of high performance liquid chromatography system (hplc) with a glassy carbon working electrode of electrochemical detector is set up for quantitative detection of  trace amount of nitrite ion (no2¯) in aqueous protein containing cell lysate, cell media, plasma, serum, urine and other body fluids. the solid extraction  reversed phase cartridges (sep-pak) are used for dep...

This article reports the ginger protease extraction and purification methods from fresh ginger rhizome. As to ginger protease extraction, we adapt the steps of organic solvent dissolving, ammonium sulfate depositing and freeze-drying, and this method can attain crude enzyme powder 0.6% weight of fresh ginger rhizome. The purification part in this study includes two steps: cellulose ion exchange...

Ion-pair reverse-phase HPLC–inductively coupled plasma (ICP) MS was employed to determine arsenite [As(III)], dimethyl arsenic acid (DMA), monomethyl arsenic (MMA) and arsenate [As(V)] in Chinese brake fern (Pteris vittata L.). The separation was performed on a reverse-phase C18 column (Haisil 100) by using a mobile phase containing 10 mM hexadecyltrimethyl ammonium bromide (CTAB) as ion-pairin...

The requirements for the transfer of (14)C-phenylalanine from yeast soluble ribonucleic acid to protein in vitro by rice (Oryza sativa L. var. Bluebonnet) ribosomes have been investigated. An absolute requirement for polyuridylic acid, 2-mercaptoethanol, guanosine triphosphate, magnesium, and potassium or ammonium ions and ribosomes has been demonstrated. Ribosomes washed in 0.5% sodium deoxych...

Derivatization of peptides as quaternary ammonium salts (QAS) is a promising method for sensitive detection by electrospray ionization tandem mass spectrometry (Cydzik et al. J. Pept. Sci. 2011, 17, 445-453). The peptides derivatized by QAS at their N-termini undergo fragmentation according to the two competing mechanisms - charge remote (ChR) and charge directed (ChD). The absence of mobile pr...

We have recently shown that 2-aminoimidazole is a superior nucleotide activating group for nonenzymatic RNA copying. Here we describe a prebiotic synthesis of 2-aminoimidazole that shares a common mechanistic pathway with that of 2-aminooxazole, a previously described key intermediate in prebiotic nucleotide synthesis. In the presence of glycolaldehyde, cyanamide, phosphate and ammonium ion, bo...

The ion exchange reaction between ammonium cyanoureate NH4[H2NC(=O)NCN] and zinc chloride yielded single crystals of the urea derivative cyanoguanylurea H2NC(=O)NHC(NH2)NCN, which was obtained as a by-product alongside zinc cyanoureate and traces of ammonium chloride. It is assumed that owing to its Lewis and Brønsted acidity, the hydrated Zn2+ ion acts as a catalyst, promoting the degradation ...