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BioPhotometer:

Does room light effect the reading when using the BioPhotometer? Do you need to cover your sample?

No, the detector and the light source are recessed so room light does not affect the measurements taken by the BioPhotometer, so you do not need to cover your sample.

How can I improve the consistency of my results when I am using the BioPhotometer?

If you observe inconsistency in results, double check that your sample is thoroughly mixed. DNA or RNA solutions may be viscous. If the solution is not homogenous then OD values can vary from reading to reading. It is important to mix your sample in a separate tube and then transfer it to the cuvette. Especially with small sample sizes, mixing in the cuvette can be inefficient. In addition, spinning down your DNA or RNA solution prior to taking any measurements can eliminate particulates, which also could cause erroneous readings.

Why can’t I print from my BioPhotometer?

The dip switch settings on the printer are most likely set incorrectly. There are three dip switches and each switch contains 8 switches within. To confirm that the settings are correct call or e-mail Eppendorf for a copy of Seiko thermal printer switch settings. If your dip switch settings are correct, try changing the cable. Many times a faulty cable can interrupt communication between the two units.

What is the warranty period for the BioPhotometer?

The BioPhotometer has a warranty period of two years.

Which cable can be used to connect the BioPhotometer and the Thermal Printer?

The Thermal Printer is connected to the BioPhotometer using the Eppendorf Printer Cable (order no. 0013 610.517).

What are the dimensions and weight of the DPU-414 printer?

Dimensions of the DPU-414 printer are 160 mm x 70 mm x 170 mm (W x H x D). It weighs approximately 400 g.

What is the light-path height of the BioPhotometer?

The light-path height of the BioPhotometer is 8.5 mm.

How many calibration curves can be stored per protein-determination method (Bradford, Lowry, BCA)?

One calibration curve can be stored per method. In addition, it is possible to save a second curve under the “micro” method.

What is the smallest amount of DNA that can be reasonably measured?

The detection limit can be derived from the possible measuring error. An error of <= 0.003 Absorbance units can be expected, which is equivalent to a concentration of 0.15 µg/ml dsDNA. For example, if an absorbance value of approximately 0.050 is measured at 260 nm, then we know the concentration to be 2.5 µg/ml dsDNA, (because A is multiplied by the factor of 50 as the known standard and is preprogrammed for dsDNA). Therefore, the concentration determined from the measured value is between 2.35 and 2.65 µg/ml utilizing an error rate of 0.003 A (2.5 µg/ml ± 0.15 or 6%). Therefore, the amount of error that you will allow in your application will determine what the lowest amount of DNA you can reasonably measure. As the actual concentrations decrease, the error rate of 0.003 A becomes a higher percentage of the reading.

Can cuvettes from other manufacturers be used?

Yes, on condition that the specific dimensions of the cuvettes enable them to fit into the BioPhotometer and that they have a measuring window in line with the light-path height of the BioPhotometer (8.5 mm).

Is the OD 600 method a linear method? Which influences must be taken into account?

The measuring method is non-linear when the absorption curve is monitored across wide OD ranges and dilutions. The values are organism-dependent (size, shape) and device-dependent (light path geometry, proportion of scattered light rays measured). Therefore a calibration curve for each organism and for each device must be determined based upon the actual cell number. When the curve is known, it is possible to carry out measurements in those areas that run virtually linearly. In the course of one working day, the BioPhotometer is used repeatedly at irregular intervals.

Do you recommend that the device be switched on and off several times throughout the day or should the BioPhotometer be ready to measure at all times?

The operating life of the xenon lamp is affected neither by switching it on and off several times a day nor by leaving it on for several hours at a time. For this reason, users may decide for themselves whether the BioPhotometer should be switched on and off several times or should be left running permanently. The xenon lamp is “”active”” during measurement only; it then transfers to a Standby mode.

Is it possible to perform quantitative measurements using the BioPhotometer?

Yes. DNA/RNA/Oligos are quantified at 260 nm (UV), whereas proteins are measured either directly at 280 nm or with colorimetric assays, such as Bradford, Lowry or BCA. In addition, bacteria suspension can be determined at 595 nm (OD 600).

How do I set up the DPU 414 Printer for the BioPhotometer?

Download this PDF which contains parameters for DPU set up. ( PDF 72k)


UVettes

Can I reuse the UVettes?

Eppendorf recommends that the UVette be discarded following the sample measurement in order to guarantee contamination-free analysis. Cleaning processes and/or multiple use of an UVette may damage the quality of the optical surfaces, particularly in the sensitive UV-range. Even the slightest changes in the measuring area affect the quality of the results, even though this is not immediately visible.

When do you recommend using the 2 mm light path of the UVette versus the 10 mm?

In general, the absorbance should be within the linear measuring range of the BioPhotometer (OD: 0.0 –3.0). As a rule, users work with an absorbance of about 2.0. When working with a higher concentration sample that has an absorbance greater than 2.0, we recommend measuring using the 2 mm light path. For samples with a normal or a lower concentration, the 10 mm light path is suitable.

Should the same UVette be used for the measurement of the blank and of the sample?

The same UVette must be used for both measurements, since the self-absorption of every UVette is different. Using the same UVette guarantees that exact values are obtained.

Is a transmission curve (self-absorption of the UVette at different wavelengths) available for the UVette?

Yes, this can be found in the pack insert of the UVette. Copies are available from our Application Support ([email protected]).

What is the UVette made of?

The UVette is made of a UV-transparent plastic. It is free of fluorpolymers and other halogenated hydrocarbons, and is suitable for all commonly used methods in the fields of molecular biology and biochemistry.

Which reagents is the UVette resistant to and which reagents is it not resistant to?

Resistant to

Acids, for example:
  • acetic acid 96%
  • perchloric acid 10%
  • nitric acid 65%
  • hydrochloric acid 36%
  • sulfuric acid 40%
  • trichloroacetic acid 40%
Alkaline solutions, for example
  • ammonia solution 25%
  • sodium hydroxide solution 20%
Alcohol, for example
  • ethanol
  • isopropanol
  • methanol
And other important reagents, for example
  • acetone
  • DMSO 10%
  • formaldehyde 40%
  • water-saturated phenol
Non-resistant to non-polar solvents, for example
  • gasoline
  • chloroform
  • diethyl ether
  • hexane
  • oleic acid
  • petroleum ether
  • carbon tetrachloride
  • toluene
*All substances were tested at room temperature over a period of 24 hours.
What are the minimum and maximum filling volumes of the UVette?

The minimum filling volume of the UVette is 50 µl and the maximum is 2,000 µl. Make sure that there are no air bubbles in the solution, and that there is no residual liquid on the inner wall of the UVette. For this reason when pipetting the minimum volume, it is best to pipette the 50 µl directly into the lower part of the UVette.

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