The 8-sample retention system used by the Thermo Scientific NanoDrop 8000 spectrophotometer is one of the key features of the instrument. Eight samples are simultaneously captured between an array of upper and lower optical surfaces, eliminating the need for cuvettes and capillaries. This saves on the cost of disposable cuvettes and/or on the time and effort spent in cleaning reusable ones.
With the sample apparatus open, eight 1 µl samples are pipetted directly onto the array of optical surfaces.
When the sample apparatus is closed, the sample arm slightly compresses the droplets and a sample column is formed. Surface tension alone holds the samples in place.
A spectral measurement and quantification of each sample is made based on the tightly controlled path length.
When the measurements are complete, the sample apparatus is opened and the samples are simply wiped from both upper and lower optical arrays with an ordinary dry laboratory wipe.
Since the samples are not contained in a secondary vessel, the samples directly wet the system optics, reducing the variations resulting from changing and/or repositioning cuvettes. When the samples are removed, the optics can be easily cleaned making it possible to measure successive sample varying by more than 1000 fold in concentration with no carryover.
When measuring samples in a 96-well format on the Thermo ScientificNanoDrop 8000 Spectrophotometer, an eight-channel pipettor is used to draw 1 ul samples from a microtiter plate which are then dispensed onto the eight optical measurement surfaces. The Sample Position Illuminator keeps track of the samples to be measured by lighting up wells from beneath the plate. This helps the user readily identify which wells to draw from for the next measurement, thus reducing fatigue and human error. The sample position illuminator is simple to use. Prior to measurement, the user selects the samples to be measured from the on screen position indicator (selected wells are in green).
The sample position illuminator then lights up the corresponding wells of the plate that are to be measured and the user then simply draws from the illuminated wells.