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Sulfosalicylic acid is used in urine tests to determine urine protein content. The chemical causes the precipitation of dissolved proteins, which is measured from the degree of turbidity. [1] It is also used for integral colour anodizing. With water it is used as a shuttle solution for the CAS assay to test for siderophore.
Concentrated nitric acid is added to a protein solution from the side of the test tube to form two layers. A white ring appears between the two layers if the test is positive. [1] Heller's test is commonly used to test for the presence of proteins in urine. [2] This test was discovered by the Austrian Chemist, Johann Florian Heller (1813-1871).
It is advised to check the references for photos of reaction results. [1] Reagent testers might show the colour of the desired substance while not showing a different colour for a more dangerous additive. [2] For this reason it is essential to use multiple different tests to show all adulterants.
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).
The different colours are a result of the different charged states of the dye molecule. In the red form, all three nitrogen atoms carry a positive charge. The two sulfonic acid groups have extremely low pK a and will normally be negatively charged, thus at a pH of around zero the dye will be a cation with an overall charge of +1. The green ...
The results of this test must be interpreted carefully. The person's medical risk factors determine at which increment (5 mm, 10 mm, or 15 mm) of induration the result is considered positive. [12] A positive result indicates TB exposure. 5 mm or more is positive in An HIV-positive person; Persons with recent contacts with a TB patient
False positive COVID-19 tests—when your result is positive, but you aren’t actually infected with the SARS-CoV-2 virus—are a real, if unlikely, possibility, especially if you don’t perform ...
An anti-semenogelin antibody is fixed at the test line. If human semenogelin is present in the sample, it will form an antigen-antibody-colloidal gold complex upon deposition. These complexes react with the antibodies fixed at the test line to form a visible red line indicating the presence of human semenogelin, and therefore, human semen. [4]