Wikipedia
In chemistry, work-up refers to the series of manipulations required to isolate and purify the product(s) of a chemical reaction.
Typically, these manipulations may include:
- quenching a reaction to deactivate any unreacted reagents
- cooling the reaction mixture or adding an antisolvent to induce precipitation, and collecting or removing the solids by filtration, decantation, or centrifugation
- removal of solvents by evaporation
- separating the reaction mixture into organic and aqueous layers by liquid-liquid extraction
- purification by chromatography, distillation or recrystallization
For example, the Grignard reaction between phenylmagnesium bromide and carbon dioxide in the form of dry ice gives the conjugate base of benzoic acid. The desired product, benzoic acid, is obtained by the following work-up:
- The reaction mixture containing the Grignard reagent is allowed to warm to room temperature in a water bath to allow excess dry ice to evaporate
- Any remaining Grignard reagent is quenched by the addition of water
- Dilute hydrochloric acid is added to the reaction mixture to protonate the benzoate salts, as well as to dissolve the magnesium salts. White solids of impure benzoic acid are obtained.
- The benzoic acid is decanted to remove the aqueous solution of impurities, more water is added, and the mixture is brought to a boil with more water added to give a homogeneous solution.
- The solution is allowed to cool slowly to room temperature, then in an ice bath to recrystallize benzoic acid.
- The recrystallized benzoic acid crystals are collected on a Buchner funnel and are allowed to air-dry to give pure benzoic acid.
Work-up may refer to:
- Medical evaluation, possibly including medical history, physical examination, and other tests
- Work-up (chemistry)
Usage examples of "work-up".
Stevens is a twenty-two-year-old muscular Caucasian male institutionalized since age four with undiagnosed mental retardation, who is admitted for definitive work-up and repair of his congenital cardiac abnormality thought to be a septal defect .
Given the stress of the dementia work-up, every organ system crumpled: in a domino progression the injection of radioactive dye for her brain scan shut down her kidneys, and the dye study of her kidneys overloaded her heart, and the medication for her heart made her vomit, which altered her electrolyte balance in a life-threatening way, which increased her dementia and shut down her bowel, which made her eligible for the bowel run, the cleanout for which dehydrated her and really shut down her tormented kidneys, which led to infection, the need for dialysis, and big-time complications of these big-time diseases.
But when the work-up doubles back on the identity of parent or legal guardian, the girl only shrugs.
Run: part of the Gastrointestinal work-up, a series of tests, including upper GI series with small bowel follow-through, barium enema, sigmoidoscopy, liver scan, gallbladder series etc.
Her work-up had not been completed and no differential diagnosis was listed in the chart.