A simple device has been built that will allow spectrophotometric measurements of very small samples (2ndash;5 mgr;lthinsp;) in capillary tubes. This attachment is sized to fit in the standard 12.5times;12.5 mm2sample holder slot of commercially available spectrophotometers. A cylindrical quartz lens focuses light from the source onto quartz (for UV measurements and visible measurements) micropipettes and a second lens recollimates the light before it is sent to the detector to optimize the light efficiency. This device was initially used to measure the concentration of small samples of concentrated pUC 8 DNA which has an absorption line at 260 nm.
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