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6. MicroArray
The capability to pre-select viable fluorescent-tagged hybridization probes for gene expression in microarrays can eliminate potentially
flawed samples and improve research effectiveness. The NanoDrop
fluorescent dye, allowing detection at dye concentrations as low as 0.2 picomole per microliter.
Fluorescent Dye Selection
There are currently nine fluorescent dyes that are hard-coded for use with the MicroArray module (see table below). Users can also
enter & save fluorescent dyes not coded within the ND-1000 software using the 'Dye/Chromophore Editor' button found in the main
menu.
Dyes can be selected using the scroll arrows or by highlighting the Dye 1 or Dye 2 box. The respective absorbance
extinction coefficient, and 260nm and 280nm % corrections will be automatically utilized for measurement and concentration calculation.
The default settings from NanoDrop remain Dye 1 set to Cy3 and Dye 2 set to Cy5. In addition to the fluorescent dyes available from
the drop-down menu, an option entitled 'None' is also available. Selecting 'None' disables the respective calculations & numeric
displays corresponding to that dye.
Note: Please refer to the dye manufacturer for the appropriate correction factors for user entered dyes.
Sample Volume Requirements
Field experience has indicated that 1 ul samples are sufficient to ensure accurate and reproducible results when measuring aqueous
nucleic acid samples containing incorporated fluorescent dyes. However, if you are unsure about the surface tension properties of your
sample or your pipettor accuracy, a 1.5-2 ul sample is recommended to ensure that the liquid sample column is formed and the light
path is completely covered by sample.
Measurement Concentration Range
®
The NanoDrop
ND-1000 Spectrophotometer will accurately measure fluorescent-dye and nucleic acid concentrations up to 100
pmols/ul (Cy3) and 750 ng/ul (DNA) respectively without dilution. A table of sample concentration ranges is listed below.
Sample
Type
Cy3, Cy3.5, Alexa Fluor
555 and Alexa Fluor 660
Cy5, Cy5.5 and Alexa
Fluor 647
Alexa Fluor 488 and
Alexa Fluor 594
Alexa Fluor 546
Unique Screen Features
Detection
Approx. Upper
Limit
Limit (pmol/ul)
(pmol/ul)
0.20
100
0.12
60
0.40
215
0.30
145
®
ND-1000 Spectrophotometer measures the absorbance of the
Typical Reproducibility
(minimum 5 replicates)
(SD= pmol/ul; CV= %)
sample range 0.20-4.0 pmol/ul: ± 0.20 pmol/ul
sample range >4.0 pmol/ul: ± 2%
sample range 0.12-2.4 pmol/ul: ± 0.12 pmol/ul
sample range >2.4 pmol/ul: ± 2%
sample range 0.40-8.0 pmol/ul: ± 0.40 pmol/ul
sample range >8.0 pmol/ul: ± 2%
sample range 0.30-6.0 pmol/ul: ± 0.30 pmol/ul
sample range >6.0 pmol/ul: ± 2%
6-1
Section 6- MicroArray
wavelength,
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