The BioUltra label has been assigned to a group of basic reagents with a well-defined high purity. These reagents are principally used in biochemistry and life science applications. BioUltra products are basic reagents designed for use in biochemical and biological techniques where large amounts of reagent are required in comparison to the quantities under investigation.
The BioUltra Reagent Certification guarantees:
BioUltra reagents are carefully handled to ensure a very high quality product at the time of packaging.
BioUltra Reagents Tests
Solubility and Appearance in Solution
Solubility is usually checked in a 1 M test solution in water (Fluka No. 95304) at 20 °C. Where appropriate, more diluted or more concentrated solutions in water or hydrochloric acid are used. The appearance of the solution is checked for absence of foreign color and is described as follows: Solubility: completely soluble, colorless (0.5 M in water, 20 °C)
Checking for Insoluble Matter by Filter Test
Filter test results are the appropriate criteria for confirming the absence of insoluble matter. 20 ml of the test solution are filtered through a Millipore 0.45 mm filter membrane. After air-drying the filter membrane is compared with a blank. This result is expressed as follows: Insoluble matter: passes filter test.
Ultraviolet Absorption (UV)
The UV absorption of the appropriate test solution is measured at wavelengths of 260 and 280 nm in a 1 cm quartz cell against the solvent. The figures are shown in dimensionless absorption units (OD). These results are given as: UV: A260< 0.02 A280< 0.01 (3 M in water).
pH of Solution
The pH of the test solution is measured by a combined glass electrode at 20 °C. The results are given in pH units (-log [H+]). Very dilute solutions including those in hydrochloric acid are not determined. The result is expressed as follows: pH: 3.0-4.0 (0.5 M in water, 20 °C)
BioUltra reagents for Molecular Biology
Reagents belonging to the group BioUltra for Molecular Biology are tested, in addition to the general BioUltra tests, for their suitability in molecular biology experiments. Sigma guarantees for its molecular biology reagents absence of the following enzyme traces:
Absence of the above mentioned enzyme traces is measured by the following methods:
RNase traces are determined by following the fluorescence decrease of the MS 2 RNA complex with a fluorescing RNA intercalator of the appropriate wave length.
DNase traces are measured by following the fluorescence decrease of a complex of the plasmid DNA with a fluorescing DNA intercalator.
Protease traces are checked by following the fluorescence increase in a system containing the substrate resorufin-casein.
The tests for phosphatase traces are performed by measuring the fluorescence increase in a system containing the substrate 4-methylumbelliferyl phosphate.
Analysis and BioUltra Reagent Guarantee
In addition to the previously described tests (see BioUltra Certification and special quality for molecular biology), BioUltra Reagents are subject to strict analysis in our laboratories to meet the indicated guarantee requirements. The following list provides information on the methods.