Please note that the NanoDrop 1000 is no longer available. It has been replaced by the NanoDrop 2000
Review of NanoDrop 1000:
The NanoDrop® ND-1000 is a full spectrum (220-750nm) spectrophotometer that provides scientists with a simple and robust instrument for quantification and evaluation of purity of samples, such as proteins and nucleic acids. The technology is based on a patented sample retention system, which allows for the analysis of sample sizes as small as 0.5ul, without the need for awkward cuvettes or capillaries. In addition, there is no need for sample dilution in most cases and the high absorbance capability of the instrument is reported to be 50 times that of traditional spectrophotometers.
I frequently use the NanoDrop for both quantification and purity analysis of purified RNA and DNA samples and would thoroughly recommend this instrument for this purpose. I find the instrument both incredibly fast and simple to use in comparison to older cuvette or capillary based methods and the small test sample size requirement means minimal samples loss. The small and compact instrument is extremely straightforward to use and comes with a user-friendly software package that provides facilities to save and print quantification reports.
For nucleic acid quantification, the user must first select 'nucleic acid' from the menu. There is then the option to specify between RNA, DNA and ssDNA and name the sample within the software. The user then lifts the pedestal arm and pipettes an approximately 1ul water sample onto the pedestal, closes the arm and presses the 'blank' button to blank the instrument. Following this, the pedestal needs to wiped with a clean tissue and the user can pipette 0.5-2ul of nucleic acid sample onto the pedestal and press 'measure'. Closing the arm allows a sample column to form and once the user selects ‘measure’, the pedestal moves to automatically adjust for an optimum path length of 0.05mm-1mm. Sample measurement takes approximately 10s and results in a spectrum graph to allow to user to visualize each plot. The absorbance reading is directly converted into concentration (ng/ul) and both 260/280 and 260/230 absorbance ratios are given, which can be indicative of purity. For nucleic acids, the 260/280 ratio is used to access purity and a ratio of ~1.8 for DNA and ~2.0 is generally accepted as ‘pure’. Any ratios that are significantly lower than this can indicate the presence of contaminants, which absorb strongly at 280nm, such as phenol or proteins. The 260/230 measurement is used as a secondary measure of purity and these ratios are often higher than the 260/280 for ‘pure’ nucleic acids.
The NanoDrop® ND-1000 is a Thermo Scientific product and their website is very useful for extra support and information. In addition, they provide a free trial program for one-week, allowing the user to test out the instrument for themselves. One of the only disadvantages of the NanoDrop® ND-1000 is that it can be quite slow if a large number of sample measurements are required. However, if this is the case, Thermo Scientific also produce the NanoDrop® ND-8000 which provides the facilities to measure up to 8 samples at one time.