Abstract: A composition comprising dichloroacetic acid and glyoxylic acid, wherein, the content of glyoxylic acid is below 1000 pm, and the preparation method and application of the composition. A process for preparing the composition, comprising: mixing a dichloroacetic acid material having greater than 1000 ppm glyoxylic acid with a glyoxylic acid capture reagent, and a process for preparing oligonucleotides, comprising using the composition. It is found that glyoxylic acid is an impurity in commercially available DCA products, which may cause the oligonucleotides synthesis failure. Ion chromatography can be used to detect glyoxylic acid in dichloroacetic acid and accurately determine its concentration.

Abstract: An optical engine its use in a bench top flow cytometer, the optical engine having a set of lasers, each focused horizontally along an x-axis to a same horizontal position and vertically along a y-axis to a different vertical position along a same excitation plane of a flow cell, a set of optics that separate fluorescence of a same wavelength range into different locations in a focal plane of collection optics according to the different lasers by which the fluorescent light is excited; and a detector that selectively detects light from the different locations thereby distinguishing between fluorescence emitted within the same wavelength range as excited by the different lasers.