Can printers other than the Thermal Printer (DPU) be connected to the BioPhotometer?

With software version 1.01, it is possible to connect the Thermal Printer (DPU) only. The new version 1.20 enables other printers with a serial interface to be connected.

Is it possible to print out data in Excel formats via the RS 232 interface of the BioPhotometer?

With the new software version 1.20 and an additional PC program (option), the measured values can be transferred easily as an Excel table and can then be processed unrestrictedly using Excel.

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 A should be expected, which is equivalent to a concentration of 0.15 μg/ml dsDNA. An absorbance value of approximately 0.050 at 260 nm is measured for a sample with 2.5 μg/ml dsDNA. The concentration determined from the measured value is then between 2.35 and 2.65 μg/ml. When A = 0.020 the concentration is between 0.85 and 1.15 μg/ml. In the UVette with a sample volume of 50 μl, the concentration 2.5 μg/ml corresponds to 125 ng dsDNA.

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 is the light-center height / light-path height of the BioPhotometer?

The light-center height (= 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 per method can be stored. In addition, it is possible to save a second curve under the "micro" method.

What are the dimensions and weight of DPU Printer 414?

Dimensions of DPU Printer 4141 (W x H x D) = 160 mm x 70 mm x 170 mm; weight: approx. 400

Is BioPhotometer software version 1.20 compatible with Windows NT 4.0?

Yes. The BioPhotometer with software version 1.20 and the PC online program can be run on Win NT4.

What is the warranty period for the BioPhotometer?

The BioPhotometer has a warranty period of two years.

Can cuvettes from other manufacturers be used?

Yes, on condition that the dimensions of the cuvettes enable them to fit into the BioPhotometer and that they have a measuring window in line with the light center 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, calibration curves for each organism and for each device must be created by determining the actual cell number. When the curve is known, it is possible to carry out measurements in those areas that run virtually linearly. We are happy to send you the publication ""Turbidimetry (OD600) with absorption spectrometers"" or the industry application ""Microbiological turbidimetry using standard photometers"".

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 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).

Is it possible to use standard curves in the BioPhotometer?

Yes. Standard curves are required for the Bradford, Lowry and BCA methods, since the reagents involved are not stable. The standard curve is normally recorded on the day before sample measurement begins.

When do you recommend using the 2-mm light path of the UVette and when should the 10-mm light path be used?

In general, the absorbance should be within the linear measuring range of the BioPhotometer (OD = 0-3.0). As a rule, users work with an absorbance A = 2.0. Since a high sample concentration correlates with high absorbance values, we recommend measuring high-concentration samples using the 2-mm light path. For samples with a normal or a low concentration, the 10-mm light path is more 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.

What are the differences in self-absorption between UVettes?

The standard deviation (1 s) may be as high as < 15 mA, i.e. 70 % of all UVettes are in this range (3 s = 45 mA). For this reason, we recommend carrying out a blank measurement with each UVette prior to sample measurement. The UVette must be inserted in the same direction for both measurements.

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?

The UVette is resistant to all reagents commonly used in the field of molecular biology, such as ethanol, acidic and alkaline buffers and water-saturated phenol. It is not resistant to non-polar solvents such as chloroform, diethyl ether and toluene.

What is the minimum filling volume of the UVette?

The minimum filling volume of the UVette is 50 μl. Please 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, it is best to pipette the 50 μl directly into the lower part of the UVette.

What is the maximum filling volume of the UVette?

Up to 2,000 μl may be pipetted into the UVette