Apparatus for General Chemical Experimentation with Micrograms to Nanograms

Abstract

Qualitative investigations (25, 28, 29, 30, 91) including separation and identification by confirmatory tests, semiquantitative estimations making use of the volumes of precipitates (25, 30, 92, 93), and gravimetric (88, 89) determinations with microgram to nanogram samples can be carried out by mechanical manipulations in tiny glass capillary cones, and are nowadays well established fields. Chemical operations with micrograms to nanograms in volumes of solutions of the order of one microliter to a few nanoliters are performed in tiny capillary cones of approximately one half to a few microliters capacity. Small amounts of reagents and wash liquids are held ready for use in reagent containers which, together with the cones, are held ready on a glass carrier inside a moist cell to hinder evaporation of the small volumes of solutions. Measurement of volume is carried out in the reagent containers or in special measuring capillaries mounted on the carrier. The moist cell is mounted on the stage of a low-power microscope and is moved by means of the revolving mechanical stage of the microscope. The transfer of liquids is achieved by a micropipet operated with a suitable syringe and mechanically moved by a micromanipulator which permits displacement of the micropipet along the three spatial coordinates. The micromanipulator together with the rotating mechanical stage of the microscope provides the means for adjusting the relative positions of capillary vessels and micropipet. The separation of solids from liquids in the capillary cones is achieved by centrifugation and decantation. The mechanical and optical facilities permit the performance and observation of all necessary operations with ease and confidence.