Semi-automated ninhydrin assay of Kjeldahl nitrogen

The staining and photography of nucleic acids in polyacrylamide gels is a somewhat involved and certainly time-consuming procedure. Ultraviolet scanning methods (1) may be used to record the location of uv-absorbing bands of material in polyacrylamide gels, but this is a complicated and inefficient way of storing experimental information. Recently, we have published a method (2) for the location and isolation of nucleic acids from unstained polyacrylamide gels (entitled UV Shadowing). An extension of this method is the technique of Direct-Contact Photography.