Search results
Results from the WOW.Com Content Network
This reaction is rapid and stoichiometric, with the addition of one mole of thiol releasing one mole of TNB. The TNB 2− is quantified in a spectrophotometer by measuring the absorbance of visible light at 412 nm, using an extinction coefficient of 14,150 M −1 cm −1 for dilute buffer solutions, [4] [5] and a coefficient of 13,700 M −1 cm −1 for high salt concentrations, such as 6 M ...
The reagent used can be any substance that gives S 2− ions in such solutions; most commonly used are hydrogen sulfide (at 0.2-0.3 M), thioacetamide (at 0.3-0.6 M), addition of hydrogen sulfide can often prove to be a lumbersome process and therefore sodium sulfide can also serve the purpose. The test with the sulfide ion must be conducted in ...
Sample preparation for mass spectrometry is used for the optimization of a sample for analysis in a mass spectrometer (MS). Each ionization method has certain factors that must be considered for that method to be successful, such as volume, concentration, sample phase, and composition of the analyte solution. Quite possibly the most important ...
Reagents are "substances or compounds that are added to a system in order to bring about a chemical reaction or are added to see if a reaction occurs." [1] Some reagents are just a single element. However, most processes require reagents made of chemical compounds. Some of the most common ones used widely for specific reactive functions are ...
An assay (analysis) is never an isolated process, as it must be accompanied with pre- and post-analytic procedures. Both the communication order (the request to perform an assay plus related information) and the handling of the specimen itself (the collecting, documenting, transporting, and processing done before beginning the assay) are pre-analytic steps.
Standard solutions are generally prepared by dissolving a solute of known mass into a solvent to a precise volume, or by diluting a solution of known concentration with more solvent. [1] A standard solution ideally has a high degree of purity and is stable enough that the concentration can be accurately measured after a long shelf time. [2]
The total protein concentration is exhibited by a color change of the sample solution in proportion to protein concentration, which can then be measured using colorimetric techniques. It is named for the biochemist Oliver H. Lowry who developed the reagent in the 1940s. His 1951 paper describing the technique is the most-highly cited paper ever ...
The Griess diazotization reaction, on which the Griess reagent relies, was first described in 1858 by Peter Griess. [ 1 ] [ 2 ] The test has also been widely used for the detection of nitrates (N- oxidation state = 5+), which are a common component of explosives , as they can be reduced to nitrites (N- oxidation state = 3+) and detected with ...