Frequently Asked Questions
Select the product group below to get answers to common product questions. If you need additional help, our Scientific Support group is ready to assist you.
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I work with the Bradford protein determination method. During my latest sample measurement on the BioPhotometer the measured absorbance appeared on the display, but a concentration wasn't displayed. What causes this?
I would like to carry out a colorimetric detection on the BioPhotometer with several standards and using linear regression. Following the measurement, can I query the factor or the ascent of the calibration lines on the BioPhotometer?
In your "Tips & Tricks" list for the photometric determination of nucleic acid concentrations you say under "Cuvette handling" that for very exact measurements a cuvette error should be determined and allowed for in the measured results. How do I determine the cuvette error?
In the course of my DNA concentration determination I measured a relatively low A260 value (between 0.05 and 0.07) and a relatively high A230 value (corresponding app. to the A260 values). The A260/A230 is <2.0. What do these values say about the quality of my DNA?
Carbohydrates, aromatic groups, phenols and peptides have an absorption maximum of 230 nm.
Because the Biuret method can also be carried out at 562 nm (the absorption behavior of the Biuret reagent is almost identical in the range from 530 to 570 nm), you can measure your Biuret method on the BioPhotometer using the BCA method. Please note that you need only work with a standard for the Biuret method. The measurement of a standard curve is unnecessary.
Please check whether:
- the correct concentration unit was selected (e.g. mg/ml was chosen, but the sample has a concentration in the µg/ml range)
- an entry with decimal places was made for the standard concentrations. With an entry without decimal places, lesser sample concentrations (e.g. 0.024) cannot be recognized.
It is 3 m long.
Yes. For each colorimetric calibration saved on the BioPhotometer, all calculated parameters, such as, for example, the ascent of the calibration lines, are automatically filed in the affiliated calibration report. To call up the calibration report press the Function key, select "Calibration report" with the cursor, press the Enter key, select the desired calibration with the cursor, press the Enter key.
Please check whether the factor 1.000 is found under "Parameter" on the BioPhotometer. It is possible that the factor was accidentally reset to nil when working with the BioPhotometer. In case you continue to have difficulties with measurement, please contact our Application-Hotline: Tel. +49 180 3 66 67 89; email: firstname.lastname@example.org.
In general, the following applies: F = 1: (e x l) where F = factor [(µg/ml)-1 cm-1], e = molar extinction coefficient [M-1 cm-1], l = optical layer thickness of cuvette [cm]. For small molecules like oligonucleotides, for example, the correct extinction coefficient is determined from the base composition. As the concentration of oligonucleotides is commonly reported as mmol/liter, a millimolar extinction coefficient (E) is conventionally used in the Beer-Lambert equation by means of: E = A (15.3) + G (11.9) + C (7.9) + T (9.3) A, G, C and T here stand for the number of corresponding bases in this oligonucleotide, the numbers in brackets for the molar extinction coefficient of any deoxynucleotide at pH 7.0.
Source: Sambrook et. al. Molecular Cloning (2001).Third Edition, A8.21
Yes. Double-stranded ring-shaped DNA can be measured on the BioPhotometer using the "dsDNA" method, and single-stranded ring-shaped DNA with the "ssDNA" method.
You fill a cuvette with water and measure it as blank. Now fill another cuvette with water as well and measure this cuvette as a sample. The difference in absorption between the two cuvettes can now be identified as positive or negative absorption at the individual wavelengths. The most reliable method is to repeat the sample measurement up to three times and then to calculate the cuvette error as the mean value of the absorption differences measured.
Dust in the cuvette shaft can be carefully removed with a cotton tip. If the cuvette shaft is heavily soiled, for example with dried-on buffer residues, the cotton tip should be carefully soaked in 40% methanol beforehand.
Silicium photo diodes are used as detectors in the BioPhotometer.
The life span of the xenon lamp is influenced by neither repeated switching on and off nor by leaving it on in standby over a period of several hours. You can therefore decide for yourself. The xenon lamp is also only active during the measurement. It then switches over into standby mode.
Please note that you should measure at 260 nm for a minimum absorbance of 0.1 in order to obtain exact results. This value is independent of the measuring device and is based upon the disturbing influence of impurities and particles on the measurement result, which is especially high at A < 0.1. An A260/A230 < 2.0 can indicate impurity of the DNA sample. This is because peptides, aromatic groupes, phenols and carbohydrates absorb at 230 nm. With contaminated DNA samples you can try to clean the sample through centrifugation (at least. 5 min). Otherwise the sample must be purified again according to the protocol specifications.
Yes, if you are aware of a factor for double-strand RNA. You should enter this under the RNA method before the measurement under "Parameters". If you don't have a factor, you can carry out a calibration with a familiar dsRNA quantity and then use this to measure the unknown sample.
For purposes of data documentation, either a printer or a PC can be connected to each BioPhotometer. It is also possible to have the photometric systematic (trueness) and photometric random error (precision) of your device inspected by one of our service partners. For purposes of testing directly, we offer the user a Secondary UV-VIS-Filter.
Yes, the software is valid for the BioPhotometer plus as well as for the BioPhotometer 6131!
Yes, this is possible. You need an RS232/USB connection cable. This cable is worldwide available by the company VScom.
Please check, if all systems settings as stated in the manual in chapter 2.3 are correct.
Yes, this is possible. Click in the "work" area on "ID". Here you can connect you results to a specific series of measurement!
Yes, this is possible. Therefore you can use in the area "archive" the filter function.
No, this data will be exported automatically.
Yes, this is possible! Just click on top menu bar on "file" and "settings". In the right window you can apply a new user profile with a new password. Please note that only a new profile can apply if you are login as an administrator.
The BDTS will only be offered in English language.
No, the BDTS will only be available for Windows.
Negative A230 values are usually caused by interference components in inadequately concentrated DNA solutions. The negative value should be rectified when you use a lesser sample dilution for the next measurement. Please note that you should measure at 260 nm for a minimum absorbance of 0.1 in order to obtain exact results. This value is independent of the measuring device and is based upon the disturbing influence of impurities and particles on the measurement result, which is especially high at A < 0.1.
This measuring method is principally non-linear, when one observes the absorption curve over wide OD ranges and dilutions. The values are dependent on both the organism (size, shape) and the device (light path geometry, ratio of measured stray light radiation). A correct procedure includes the generation of a calibration graph for each organism and device by determining the actual number of cells under a microscope. When the curve shape is known it is then possible to measure in ranges that are almost linear.
Conversion is possible through calibration graphs or counting. With measurements of Escherichia coli, for example, it is possible to estimate roughly that an OD 600 between 0.5 and 1.0 corresponds approximately to a cell number between 1 x 108 and 1 x 109.
Please check whether
1.The absorbance of your DNA sample is greater than/equal to 0.1 (please note that regardless of the device used, absorption measurements of nucleic acids only deliver reliably reproducible results at absorbances of greater than 0.1. This is based upon the disturbing influence of impurities and particles on the measurement result, which is especially high at A < 0.1.)
2. Your sample was sufficiently mixed (only careful mixing of the sample can guarantee consistent measurement values)
3. There is an impurity in your sample. An indicator of a possible impurity is the relative ratio of A260/A280 or A260/A230, which with pure DNA should amount to app. 2.0 or 2.5 at pH 7-8.5. Carbohydrates, aromatic groups, phenols and peptides have an absorption maximum of 230 nm, proteins of 280 nm.
Additional literature: "Tipps and Tricks for photometric quantification of nucleic acids".
Please switch the BioPhotometer off and then on again following the installation of the program. The header line will then appear.
Wilfinger et. al* generally recommend using 1 - 3 mM Na2HPO4, pH 8.0 - 8.5 as the measuring medium for nucleic acids. For DNA measurements, our experience shows that 10 mM Tris-HCl, pH 8.0 or a TE buffer, pH 8.0 are also suitable. *Wilfinger W.W., Mackey K. and Chomczynski P. 1997. Effect of pH and ionic strength on the spectrophotometric assessment of nucleic acid purity. BioTechniques 22: 474-481.
The Bradford reagent is an aggressive substance that attacks the plastic of plastic cuvettes when the exposure time is too long. This reagent should therefore not remain in a plastic cuvette for more than 5 minutes. Fluctuating values could be caused by the fact that the Bradford reagent has already been too long in the cuvette.
Tip: Use glass cuvettes for the Bradford method.
Dimensions (WxHxD) = 160 mm x 70 mm x 170 mm; Weight app. 400 g.
The Thermal Printer is delivered equipped with an appropriate cable. Replacement cables are available from us upon request.
From software version 1.20 on you can also connect other serial and parallel printers (a converter cable is required) besides the Thermal Printer DPU 414 to the BioPhotometer. If you use the BioPhotometer with software version 1.0, you can only connect the Thermal Printer DPU 414.
Please send your Secondary UV-VIS-Filter set to your local Eppendorf partner.
From software version 1.20 on you can transfer measuring values from the BioPhotometer to a PC (respectively, in an Excel table) with the help of the BioPhotometer software package and then process them further or print them out.
We recommend checking the photometric systematic error (photometric trueness) and the wavelength systematic error (wavelength trueness) once a year using the Secondary UV-VIS-Filter set.
You can save one standard and one micro method for each protein determination method. This means that you can store two calibration curves for each protein determination method.
That depends upon the cuvette chosen. We recommend using the UVette with a minimum volume of 50 µl.
The BioPhotometer should not be used to measure an absorbance of less than 0.05 at 260 nm. This OD value corresponds to a dsDNA concentration of app. 2.5 µg/ml (= app. 125 ng dsDNA in a 50 µl preparation). Please note that you should measure at 260 nm for a minimum absorbance of 0.1 in order to obtain exact results. This value is independent of the measuring device and is based upon the disturbing influence of impurities and particles on the measurement result, which is especially high at A < 0.1.
The BioPhotometer should not be used to measure an absorbance of less than 0.05 at 260 nm. This OD value corresponds to a RNA concentration of app. 2 µg/ml (= app. 100 ng RNA in 50 µl preparation). Please note that you should measure at 260 nm for a minimum absorbance of 0.1 in order to obtain exact results. This value is independent of the measuring device and is based upon the disturbing influence of impurities and particles on the measurement result, which is especially high at A < 0.1.
Yes. This is possible with the Bradford/Bradford micro, Lowry/Lowry micro and BCA/BCA micro methods.
Factor F is calculated from the molar absorbance coefficient of a molecule in solution and the optical path length of the cuvette used (see Beer-Lambert law). The absorption behavior of nucleic acids is influenced by the aromatic rings of the bases. Here the molar absorbance coefficient of a double-stranded nucleic acid molecule with which the bases are in close contact with each other, is smaller than of a single-stranded nucleic acid molecule. It thus follows that single-stranded nucleic acid molecules have a higher rate of absorption than double-stranded molecules (Sambrook et al. 2001. Molecular Cloning 3rd edition, A8.20). With an optical path length of 10 mm and under neutral to slightly alkaline measuring conditions an optical density of 1 at 260 nm thus corresponds to approx. 50 µg/ml of double-stranded DNA, 37 µg/ml of single-stranded DNA, 40 µg/ml of RNA and appr. 30 µg/ml of oligonucleotides.
The 260 nm and 280 nm filter samples are for the testing of the wavelength accuracy, the A1, A2 and A3 filter samples for testing of the photometric accuracy (systematic and random error) of all wavelengths. The values measured with these filters must lie within the given limits. The limiting values are contained in a table found on the inside of the lid of the filter box.
As of software version 1.20 you can easily and comfortably transfer measurement data into a table calculation program such as Excel using our BioPhotometer software package. The PC online program also enables the use of the familiar printout design from the thermoprinter with a PC printer.
Precision measurement should be carried out using a semimicro-quartz glass cuvette (> 350 µl). Clear and clean solutions are suitable as the measuring medium, for example potassium dichromate (zero adjustment to water) or water (zero adjustment to air). The coefficient of variation (CV) should be smaller/equal to 1% at 1 A in line with the technical data for the BioPhotometer. Please bear in mind that the Secondary UV-VIS filter should be used for exact precision measurement and determination of both the photometric and wavelength accuracy.
It is 2 m long.
You can of course vortex and centrifuge your sample and then transfer it to a cuvette. Please make sure that the sample is transferred to the cuvette air bubble-free .
This is caused by the measurement outside of the upper measuring range (> 3.0 A).
1. Whether your cuvette is pressed firmly onto the base of the cuvette shaft. The error message "++++" indicates that the cuvette base is blocking the light beam.
2. Whether your cuvette has an optical window at 8.5 mm.
3. Whether you have sufficient blank medium in the cuvette.
Yes, the batch-specific purity grades can be downloaded at www.eppendorf.com/certificates.
Due to the modularization of purity grades, some products are labeled with more than one purity grade symbol. For example, the epDualfilter T.I.P.S. has the double seal "PCR clean "+ "Sterile" and the UVette the double seal "PCR clean" + "Protein-free" on the packing. The certification remains unaffected by the modularization.
All products certified with "PCR clean" are tested free of human DNA, DNase, RNase and PCR inhibitors. The following applies from our point of view: Where no human DNA is detected, there can also be no RNA, which is considerably more unstable.
The previous purity grades were developed due to customer requirements and new applications, in the course of the years. To meet the customer requirements for single applications even better, Eppendorf has extended the certification of the purity grades "Sterile" (now, also certified as free of pyrogenes) and "Biopur" (now, also certified as free of DNase and PCR inhibitors). In addition, the previous purity grades have been transferred to a new modular system that provides the same variety and flexibility and yet is readily understandable.
No, they are the same products as before, i.e. all specifications as dimensions remain the same. Only the packing has changed, due to the new seals. In addition, the certification of "Sterile" and "Biopur" has been extended but the entire production process was maintained.
For all purity grades, there will be new packing seals. In addition, there will be a further certification for the purity grades "Sterile" and "Biopur". "Sterile" will certify sterility and also the freedom of pyrogenes. The purity grade "Biopur" also includes the freedom of DNase as well as of PCR inhibitors.
Yes, if no batch attachment is required for the application, products of the old and new modular purity grades can be used, as their specifications are the same.
In general, the absorbance should be within the linear measuring range of the spectrophotometer (measuring range of Biophotometer: A = 0–3.0). For samples with a normal or a low concentration, the 10-mm light path is more suitable. For high-concentration samples (with A > 2.5), we recommend using the 2-mm light path. (An absorbance > 2.5 correlates to > 125 µg/ml dsDNA and > 100 µg/ml RNA respectively.)
The UVette is resistant to:
- liquid solutions in the pH 0-14 range
- pure acetic acid
- acetone, butanone
- polar organic solvents.
It is not resistant to:
- chlorinated hydrocarbons
- aromatics such as benzene, toluene, xylene.
Please find attached a file for further information.
The UVette can in principle be used in devices with which good results have already been attained using ultra micro cuvettes. To select the correct adapter, you need to know the light path height of your photometer. A summary of "UVette adapters" lists the relevant UVette adapters for numerous devices. If your device is not on the list, please ask the device manufacturer for the light path height of your device or contact our Application Hotline (Tel. +49 1803 666 789; email@example.com).
The material characteristics of the UVette are identical within a temperature range between room temperature and 40 °C. Measurement of samples between 80 -100 °C is not possible.
We recommend 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.
No. This is because autoclaving can result in distortion of or changes to the optical characteristics of the UVette material. However, we deliver the UVette already free of DNA, RNase and protein.
No. However, as with quartz glass cuvettes, it is important to make certain that the UVette is placed in the same direction in the cuvette shaft for both the blank and the sample measurement.
Because the self-absorbance values of the UVettes vary somewhat from one another, ideally, the same UVette should be used for both measurements.
The light path height of a photometer informs you at what height, in relation to the bottom of a cuvette, the light beam of the photometer occurs.
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. Tip: pipette the 50 µl directly into the lower part of the UVette.
All UVette adapters have dimensions of 12.5 x 12.5 mm. These correspond to the standard dimensions for cuvettes with 1 cm optical path length.
The arrow serves as an orientation aid in two ways. First, it clearly shows the 10 mm light beam of the UVette. It also makes it easier to note the selected direction of the UVette in the cuvette shaft for the blank measurement.
Yes. Each UVette is packaged in such a way that the cuvette opening points toward the tear-strip of the blister-pack. In this way you can be sure not to touch the optical window of the UVette when tearing open the blister-pack.
The self-absorbance of the UVette is < 0.5; measured with water. The transmission curve is found in the operating manual for the UVette.
You can do this by first measuring the sample, then rinsing the UVette thoroughly with buffer before measuring the blank. You must then subtract the blank value from your sample result.
Yes, this can be found in the pack insert of the UVette.
With the Assay 490 method cytotoxicity assays can be evaluated with the BioPhotometer plus via endpoint detection. This assay is applied for testing the vitality of living cells. The assay is based on a lactate dehydrogenase reaction combined with a specific catalyst whereas the endproduct “formazan” can be detected at 490 nm in the BioPhotometer plus. Like in the method “Assay 340” the evaluation of the results could be done via a factor,a standard or a standard curve.
All methods of the BioPhotometer are still maintained. Furthermore in the BioPhotometer plus more methods are available compared to the BioPhotometer. Therefore a reorganization of the keypad was necessary: All related methods are summarized in one group of methods. For instance, in the method group “Protein” you will find all methods for protein determination like the colorimetric assays Bradford, Lowry, BCA as well as protein direct measurements.
With the BioPhotometer plus 32 methods (23 programmed and 9 freely programmable methods) can be used. In the precursor BioPhotometer only 9 methods were available.
With the new BioPhotometer plus additional wavelengths at 340 nm, 405 nm, 490 nm, 550 nm and 650 nm can be applied. Two of these wavelengths have been changed: 340 nm instead of 320 nm, 550 nm instead of 562 nm. These changes do not effect the performance of any method.
Yes, this is correct. Due to this change more applications are possible with the BioPhotometer plus, e.g., endpoint measurement of NADH based enzyme assays. The turbidity correction at DNA, RNA and protein measurements can also be carried out at 340 nm with the same sensitivity.
These methods are needed for the detection of fluorescent dye labeled biomolecules, like DNA, RNA or protein. With this application it is possible to check the quality of probes that should be used for microarray experiments. The quality of the probe will be indicated by the FOI (Frequency of incorporation) and the concentration of the incorporated dye.
FOI means “Frequency of incorporation”, indicating the incorporation rate of dye–molecules into a biomolecule (e.g., molecules dye/kb DNA). This function will be available in the methods Dye550 and Dye650, respectively.
This depends on the fluorescent dye. For cyanine dyes (e.g., Cy3) a FOI value of 15 but not more than 45 molecules fluorescent dyes / 1000 nucleotides is recommended.
No. The unit for the dye concentration is defined permanently with "pmol/μl" and can therefore not be changed in the parameters.
Many common fluorescent dyes, e.g., Cy3 and Cy5, show also little absorbance at 260 and 280 nm. This may lead to minute deviations when measuring the dye labeled DNA, RNA or protein in the BioPhotometer plus. This deviation can be corrected by a correction factor. The correction factors for Cy3, Cy5, ALEXA 555/647 are already programmed. For correction factors for other fluorescent dyes please contact the manufacturer directly.
This method is used for the evaluation of NADH based enzyme reactions. The enzymatic consumption will be analyzed via endpoint detection. NADH can be detected with the BioPhotometer plus at 340 nm. The evaluation of the results could be done via a factor, a standard or a standard curve.
This method is for endpoint detection of enzymatic consumption of artificial substrates. These artificial substrates serve as indicators for the activity of specific enzymes, e.g., beta-galactosidase assay or alkaline phosphatase assay. The products of the enzymatical degradation are generally para- or orthonitrophenol (pNP oder oNP). Both chemicals can be detected in the BioPhotometer plus at 405 nm. Like in the method “Assay 340” the evaluation of the results could be done via a factor, a standard or a standard curve.
With the optical pathlength of 0.2 mm microliter cell like the Hellma ®TrayCell (0.2 mm lid) can be used directly in the BioPhotometer plus without using any “virtual” dilution factors.
With the absorbance key it is possible to measure the absorbance of a sample directly without using any calculation parameter.
With the BioPhotometer plus the wavelengths 230 nm, 260 nm, 280 nm, 340 nm, 405 nm, 490 nm, 550 nm, 595 nm and 650 nm are available. With the “absorbance” key, all wavelengths can be used for direct measurement without using any calculation factors. The data can be used for further processing.
9 wavelengths can be used with the BioPhotometer plus.
No, it is not possible to run kinetics in the BioPhotometer plus. However, due to the availability of the additional wavelengths many enzymatic assays can be carried out via endpoint detection.
No, this is unfornutately not possible, but in the result display the absorbance at 280 nm and 260 nm is shown. So it is possible to calculate the protein concetration via the "Warburg-Formula" manually: c(Protein) = 1,55 x E(280) - 0,757 x E(260). Please note that photometric measurement of the protein concentrion in the UV-range only suitable for pure and homogeneous protein solutions.
Yes, in the method group “Routine” are all methods that also can be found in the BioPhotometer plus. These methods are the detection of nucleic acids, proteins, fluorescent dye labeled biomolecules plus OD600 measurements.
All cuvettes with standard dimensions can be used (12.5 * 12.5 mm). It is important that at height of 8.5 mm the optical window is transparent for the light beam)? Please check therefore also the specification in the manual (chapter 5.2).
"Yes, this is possible. To consider the light path for the calculation of the sample concentration, this value has to be entered in the area “check parameters”. Please note, that for the use of the TrayCell a sufficient sample concentration has to be applied: For the available sample concentration we recommend the absorbance ranges (e.g. dsDNA): 0.1 mm = 500 – 5000 ng/µL 0:2 mm = 250 – 2500 ng/µL 1 mm = 50 – 500 ng/µL 2 mm = 10 – 100 ng/µL These concentration ranges for dsDNA correspond to an absorbance of 0.1 to 1 A. "
Yes, this is easily possible. However, for absorbance measurement below 220 nm you have to consider the self absorbance of the UVette. For this reason we recommend to carry out measurements in the UVette only above 220 nm.
Basically every cuvette with standard dimensions can be used for the BioSpectrometer kinetic (s. chapter 5.2 in the manual). For optimal temperature control it is important that the cuvette has direct contact with the integrated peltier-element. Most adequate cuvettes are made of glass or quartz glass. In chapter 5.3.4 of the manual an overview is shown regarding pre-incubation times for different cuvette shapes.
Because of the shape of UVette the temperature transfer is here limited we recommend conventional cells made of glass or quartz glass!
In the method, "Advanced kinetics”, the measurement of standards can be programmed. This can be used for the measurement of unknown substrate concentrations via enzyme kinetics. Moreover it is possible if a drift of the reagent solution is expected, a “reagent blank” can be measurement. The result of this measurement is than subtracted from the sample measurement. These measurements are in the method "Simple Kinetics" not possible.
No, this is due to patent reasons not possible. But you can export the graph data as an Excel file and then reprocess here accordingly.
No, also this function is due to patent reasons not possible.
The files will be exported as an Excel file.
No, this is unfortunately not possible. But it is possible to export the data to an USB-Stick. The data can then be printed from the PC over a local or network printer.
A re-import of methods is unfortunately not possible.
For the BioSpectrometer an additional filter set will be available.
No, we cannot recommend to measure samples that contain detergents
It depends, of course, on the usage of the Eppendorf µCuvette and the cuvettes shaft but a little bit play is actually normal. In any case the cuvette is automatically shifted to the correct position for the measurement.
In principle this would be possible. But it has to be kept in mind that the Bradford assay and all other colorimetric assays optimized for cuvettes with a 10 mm optical path length. Since a 10 times less optical path length is used in the Eppendorf µCuvette, the expected absorbance with a colorimetric assay will be close or under the detection limit of the Photometer. This may lead to inaccuracies by creating the standard curve.
Theoretically it is possible to measure up to 1500 µg/mL double-stranded DNA. This would be similar to an absorbance of 3, which is the maximum absorbance that can be measured in the Eppendorf BioPhotometer and BioSpectrometer. For optimal measuring results we recommend to use concentrations up 1000 µg/mL dsDNA (A=2).
This depends actually on the protein itself. Theoretically it is possible to measure up to 45 mg/mL BSA. This would be similar to an absorbance of 3, which is the maximum absorbance that can be measured in the Eppendorf BioPhotometer and BioSpectrometer. For optimal measuring results we recommend to use concentrations up 30 mg/mL BSA (A=2).
For correct results the settings for the cuvette path length has to be changed to 1 mm in the parameter section: Select first the method family (e.g. DNA). Afterward go with the “cursor” key to your desired method. Press the “parameter” key move the cursor to the cuvette path length of 1 mm. For activating the new path length press the “enter” key. To leave the parameter section press “parameter” again.
For correct results the settings for the cuvette path length has to be changed to 1 mm. In the BioSpectrometer you may change this setting at the beginning of the method easily in the "check parameters" section. Change here settings for the “cuvette” path length to 1 mm.
Always use for cleaning lint-free tissue papers. Do not use any chemicals that are not recommended in the operation manual. Particularly substances that tend to corrosion such as acids or bases should be avoided.
One reason can be, that the volume of the used sample was simply too low. Another possibility is that after purification of DNA samples it may appear that there is still high amount of protein inside the sample. This may lead to a reduced surfaced tension of the liquid. This problem could be solved by slightly increasing the measuring volume. If solutions are containing detergent, it may appear that liquid column cannot be formed at all. In this case the sample should be measured in a cuvette (e.g. Eppendorf UVette).
It may be that not the right parameters are adjusted. Please check in the device if the programmed optical path length corresponds with the light path of the Eppendorf µCuvette.
Unfortunately we cannot recommend this. The Eppendorf µCuvette is specialized and optimized for the usage in Eppendorf Photometer.
Please check in the measuring results, e.g. if you want to determine the DNA concentration in your sample, if the purity ratios (260/280 or 260/230) are unusually high or low. Also a high background signal indicated by a high absorbance at 320 or 340 nm (A>0,1), can be a sign for a non-formed liquid-column. Please check also the scan result when using a BioSpectrometer for your measurement. If during DNA-measurements a typical absorbance curve is not displayed, the liquid column should be checked, too.
Proteins can reduce the surface tension in aqueous solutions, so that liquid column cannot correctly be formed. To increase the volume may help to form the liquid column completely.
Alternatively you may program also a dilution. Programming a 1:10 dilution before the measurement will lead to the same result.
The Eppendorf µCuvette can be used for all Eppendorf BioSpectrometer and BioPhotometer.
Since a 10 times smaller optical path length is used also the measured absorbance should be 10 times smaller. For this reason the result should be 0,12.
Nucleic acids could be removed easily with water. But it is also possible to clean the cuvette with lint-free paper tissue soaked with 6% sodium hypochlorite to remove nucleic acid contaminations.
There is no specific direction recommended. The Eppendorf µCuvette has to be placed in cuvette shaft, that the optical window is aligned with the direction of the light beam of Bio- or BioSpectrometer. But it is necessary that blank and sample are measured in the same direction.
No, unfortunately we cannot recommend this.
Yes, this is possible without any restrictions
The smallest volume should be at least 1.5 µL.
This depends also to some extend to on the proteins. We recommend a volume of at least 3 µL.
No, this is unfortunately not possible. The BioPhotometer D30 is a fix wavelength photometer for specific methods.
The wavelengths 230, 260, 280, 320, 340, 405, 490, 562, 595 und 600 nm could be applied.
Preprogrammed are all nucleic acid and protein detection methods and the OD 600 method for the determination of the optical density of bacterial or yeast cultures. Protein can be detected at 280 nm and via colorimetric assays like the BCA, the Bradford or the Lowry method.
No, this is unfortunately not possible. But this is also not necessary since the results are exported directly as Excel-files. An additional program for data management is therefore not necessary.
With the "impurity scan" the absorbance of a certain wavelength range is shown for nucleic acid and protein measurements. With this function impurities in the sample can be easily detected via deviations from the known curve.
This function is available for nucleic acid and protein detections.
For protein measurements it is the wavelength range from 245-350 nm and for nucleic acids the range from 225-350nm.
No, unfortunately both options are not possible. This can be done only in the BioSpectrometer
Yes, this is of course possible! Please check, that the cuvette with the required light beam hight of 8.5 mm is applied. Furthermore it is necessary for the precise calculation of the sample concentration that the correct light path length is set in the parameter section (stated on the lid)
Like for the BioSpectrometer the cuvette path lengths of 10, 5, 2, 1, 0.2, 0.1 mm could be programmed.
Yes, this is possible. We offer a calibration filter set especially for the BioPhotometer D30.
The data will be exported as Excel-files
Yes, this is possible! In the method you can select in the section "print&export" specific data packages and specific results for the export.
This depends on the method. The free programmable methods offer 18 different kind of SI units. But it is possible at any time to edit new SI-Units?
Yes, this is possible. Select in the "parameter" section of the method "protein". With "edit" a calculation tools for protein factor starts. Here, you may set the factor for the new protein directly. It is also possible to calculate the factor via the absorbance coefficient and the molecular mass of the protein or via its value "A0.1%"
The meaning of A0,1% is the absorbance of the Protein with a concentration of 1mg/ml.
About 100 methods can be stored in the BioPhotometer D30 or the BioSpectrometer.