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The Liebermann reagent named after Hungarian chemist Leo Liebermann (1852-1926) is used as a simple spot-test to presumptively identify alkaloids as well as other compounds. It is composed of a mixture of potassium nitrite and concentrated sulfuric acid. [1] [2] 1 g of potassium nitrite is used for every 10 mL of sulfuric acid. [3]
DMPX (3,7-dimethyl-1-propargylxanthine) is a caffeine analog which displays affinity for A 2 adenosine receptors, in contrast to the A 1 subtype receptors. [1] DMPX had 28 times and 15 times higher potency than caffeine in blocking, respectively, the peripheral and central effects of the adenosine agonist NECA .
Interactions between chemical compounds also is a frequent area of taxonomy, as are the major organic chemistry categories (protein, carbohydrate, lipid, etc.) that are relevant to the field. In the field of aroma and flavor alone, Flament gives a list of 300 contributing chemicals in green beans, and over 850 after roasting.
Bio-layer interferometry (BLI) is a label-free technology for measuring biomolecular interactions [27] [28] (protein:protein or protein:small molecule). It is an optical analytical technique that analyzes the interference pattern of white light reflected from two surfaces: a layer of immobilized protein on the biosensor tip, and an internal ...
Caffeine content in coffee varies widely depending on the type of coffee bean and the method of preparation used; [9] even beans within a given bush can show variations in concentration. In general, one serving of coffee ranges from 80 to 100 milligrams, for a single shot (30 milliliters) of arabica-variety espresso , to approximately 100–125 ...
The dose–response relationship, or exposure–response relationship, describes the magnitude of the response of an organism, as a function of exposure (or doses) to a stimulus or stressor (usually a chemical) after a certain exposure time. [1] Dose–response relationships can be described by dose–response curves. This is explained further ...
The above photo shows the positive results of the number 2 Marquis reagent presumptive drug test when used with a sample of opium. It is the primary presumptive test used in Ecstasy reagent testing kits. It can also be used to test for such substances as opiates (e.g. codeine, heroin), and phenethylamines (e.g. 2C-B, mescaline).
is the group interaction parameter and is a measure of the interaction energy between groups. This is calculated using an Arrhenius equation (albeit with a pseudo-constant of value 1). X n {\displaystyle X_{n}} is the group mole fraction, which is the number of groups n {\displaystyle n} in the solution divided by the total number of groups.