Acidic And Basic Reagents , Handbook Of Reagent... ##BEST##
The main disadvantage of Coomassie based protein assays is their incompatibility with surfactants at concentrations routinely used to solubilize membrane proteins. In general, the presence of a surfactant in the sample, even at low concentrations, causes precipitation of the reagent. This limitation can be overcome by using Detergent Compatible Bradford Assay. In addition, the Coomassie dye reagent is highly acidic, so proteins with poor acid-solubility cannot be assayed with this reagent. Finally, Coomassie reagents result in about twice as much protein-to-protein variation as copper chelation-based assay reagents.
Acidic and Basic Reagents , Handbook of Reagent...
The Pierce 660nm Protein Assay is based on the binding of a unique dye-metal complex to protein in acidic conditions that causes a shift in the dye's absorption maximum, which is measured at 660 nm. The dye-metal complex is reddish-brown and changes to green upon protein binding. The color change is produced by deprotonation of the dye at low pH facilitated by interactions with positively charged amino acid groups in proteins. Therefore, the dye interacts mainly with basic residues in proteins, such as histidine, arginine and lysine and to a lesser extent tyrosine, tryptophan and phenylalanine.
For returning players - reactions now work over time. In general reaction rate is tied to temperature and in some cases the presence of an optional catalyst. In general Purity is tied to the purity of your reagents, and how far away from optimal your pH is. It's important to note that the basic reaction is a one size fits all while each reaction is updated over a batch of updates, so it's unlikely that they'll cause too much trouble for you. Keep your pH within 5-9 and bare in mind most reactions are exothermic now meaning they generate heat when reacting, dangerous when using certain explosive chemicals opposite is for endothermic reactions. Meth has been tweaked - and it's a tad more dangerous, since it becomes more exothermic the less pure it is and meth explodes if it gets to 380k so be careful out there Walter!.
Every chemical has an innate pH, which can be seen by pressing the cog on the dispenser. The pH of the beaker is the sum of the pHes in the mix. The pH of a beaker determines how pure a product is, for the recipes with a given pH, you want to have your pH at the centre of the limits when the reaction starts. As a reaction progresses, it's likely the pH will begin to drift, and must be compensated for either with buffer reagents or acidic/alkaline compounds. The pH range is something chemists often have to learn over several reactions, and the ChemMaster 3000 analyse function can give an insight into what pH you should be aiming for (Not in yet). Highly impure compounds are liable to affect your reaction too thus it is prudent to set your pH before reacting, as an overly impure reaction will drag the purity down of all other reagents with it.
These handbooks are actually collections of various reagents from EROS (described above) that have been compiled into smaller handbooks of similar types of reagents. Some we have in print and others are available online.
Bluing reagents, such as Scott's Tap Water, are used to change the hematoxylin from red to the traditional blue color we expect. These slightly basic solutions chemically alter the dye to produce this color change. In some locations, the tap water contains enough minerals so that the pH causes the water to be basic enough to allow for the bluing of nuclei without the need for a bluing specific reagent. In most cases, though, labs typically add this step to ensure appropriate bluing.
This is a very different type of reaction, given the triple bond between C and N.Following the Grignard attack, water will slowly displace nitrogen until it leaves as an NH3 with a ketone in its place, as demonstrated below in acidic conditions. Note: This reaction can also take place in basic conditions for a different mechanism.
The Titration handbook combines application information with the practical laboratory experience of our titration experts. This guide requires chemical knowledge, e.g. the reading of reaction equations, knowledge of important technical terms, basic knowledge of working in the chemical laboratory, as well as the handling of devices such as scales, burettes, pipettes, electrodes and the safety regulations in the laboratory.
Ignoring for the moment the different ways in which chemists writemethane and ammonia on the one hand and water and hydrogen fluorideon the other (wierd, huh?), recall that pKa values are ameasure of the acidity of a compound. Furthermore, the pKascale is logarithmic or exponential. Thus, hydrogen fluoride is1013 times more acidic than water. Similarly, water is1022 more acidic than ammonia. Knowing the relativeacidities of the compounds in Figure 1 means you also know theirrelative basicities: the amide anion is 1022 more basicthan hydroxide ion, which is 1013 times more basic thanfluoride ion. 041b061a72