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Lab scientist with Eppendorf BioSpectrometer® basic photometer in the foreground.

Fotometria

Conheça o nosso portfólio de produtos

Cubetas

Impressoras e conjuntos de filtros

Sample and Information Management

Em 1950, a Eppendorf apresentou seu primeiro fotômetro ao mercado. O portfólio atual demonstra nosso conhecimento em fotometria e permite a você selecionar combinações de instrumentos e acessórios de uma ampla gama de produtos. A linha de produtos Eppendorf Detection permite análises moleculares fáceis e eficientes que incluem a quantificação de ácido nucleico e de proteínas, estudos cinéticos, ELISAs e detecção de fluorescência. Além disso, são possíveis medições de microvolumes em todos os nossos instrumentos de detecção com a µCuvette G1.0.

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When do I need what?

Depending on the sample concentration,
different photometric approaches are
recommended:

Extinction

Quick and easy direct measurement method Harmless and stable, since no chemicals have to be used Provides information about sample purity
Harmless and stable, since no chemicals have to be used
Provides information about sample purity

Fluorescence

High sensitivity; therefore particularly suitable for the analysis of samples with low concentrations; saves valuable sample material
High accuracy due to the high specificity for the target molecule

Kinetics

Measurement over a period of time with reliable temperature control of the Reactions through the cuvette shaft with integrated Peltier element
Time-saving processing as the time window can be adjusted after the measurement, including statistical data about the curve fit

UV-Vis Samples

Quantification of nucleic acids can be performed by measuring absorbance at a wavelength of 260 nm in a UV-Vis(spectro-)photometer. The _OD260 value is used to calculate the concentration, using the sample specific factor, of the nucleic acid sample.

OD₂₆₀ = 1^* : 50 μg/ mL double strand DNA
40 μg/ mL RNA
33 μg/ mL single strand DNA

Fluorescence Samples

UV-based quantification of nucleic acids has limits which can be bypassed by using fluorescence detection, qPCR, or chip-based capillary electrophoresis systems.

The amount of nucleic acid is calculated based on the intensity of the fluorescent signal. For excitation and detection, fluorimeter or a photometer with a fluorescence module is required.

Nucleic acids quantification via fluorescence is based on fluorescent dyes which bind to the nucleic acids. Only the complex consisting of nucleic acid and dye is excited by light of a specific wavelength (dependent on the dye) and will subsequently emit light of a slightly longer wavelength.

Kinetic Process

The enzymatic activity measurements quite often need to be performed at a specific temperature. For reducing measurement variations, the cuvette shaft of the spectro meter needs to be temperature-controlled. Enzyme activity [U/mg] can be done time-consuming by hand or by fast calculation of the spectrometer. Software based »linear regression« is useful for the accurate definition of the linear range of a kinetic measurement.

Transmission Samples

Transmission is calculated from the ratio of I (light leaving the cuvette) and I0 (light entering the cuvette) and expressed in percent as %T.

As an alternative data output to absorbance or concentration, the pre-programmed method »Transmission« of BioPhotometer D30 and BioSpectrometers provides you the percentage transmission of the sample. When using the »Transmission« method, the light trans mittance of the sample is given as T% instead of the absorbance, which is directly used to calculate the sample concentration. These raw data can also be used as a basis for further own calculations.

T = I/I0
%T = I/I0 * 100
The photometer automatically calculates the absorbance
(A) from the measured transmission (T).
A = -log10T = lg(I0/I)

Annoyed by uncomfortable handling?

Ergonomics is far beyond the »ergonomically designed chair«. Eppendorf started to optimize the laboratory devices regarding ergonomics already in the early 1970s.In 2003, we started the PhysioCare Concept, focusing on ergonomic liquid handling devices like our pipettes. Nowadays, the Eppendorf PhysioCare Concept is broaden up to include further laboratory products as a holistic solution to harmonize the workflow in your laboratory with your health and well-being, e.g. for the Eppendorf BioSpectrometer:

Guided software for easy handling
Clear indications at cuvette shaft for convenient handling
Direct keys for convenient handling
Small footprint to enable position in direct arm reach at your bench
Standardized »user-interface concept« for intuitive handling of devices

Further information about the Eppendorf PhysioCare Concept:

www.eppendorf.com/physiocare

Struggling with paper-based documentation?

The eLABJournal Electronic Lab Notebook offers an intuitive and flexible solution to document research and track research data like BioSpectrometer–based values. Improve efficiency when documenting, organizing, searching, and archiving collected data. With the free eLABJournal add-ons, you can extend the functionality of eLABJournal to a fully integrated Laboratory Information Management System.

Start a free 30-day trial!

Visit
www.eLABJournal.com

One of the First Photometers for Labs

You might got your basic training in the laboratory with one of ours… Based on nearly 70 years of photometry experience, Eppendorf has developed many different photometers over the time.

Can You Trust Your Results? Verification of Spectrophotometers

Many laboratories are subject to regulatory requirements that e.g. are prescribed by Quality Management Systems. These laboratories are thus obligated to test work equipment and analysis instruments, including (spectro-) photometers, on a regular basis. What if such regulations do not apply to your lab? In this case, testing is not absolutely necessary, as it is not mandatory – but does that mean it is not important?

Decades of Photometer Work

A working life – 48 years with Eppendorf, a laboratory technician remembers …

Fluorescence - useful addition to extinction?

Nucleic acids and proteins are routinely quantified using UV-Vis spectrophotometry. Occasionally, however, detection via fluorescence may prove more convenient.

Absorbance Measurements - Quick determination of sample concentration

In molecular and biochemical applications as well as in medical research, the determination of the concentrations of substances in solution is a crucial analysis

Monitoring the growth rate of the microbial culture

Can I continue with my prokaryotic cells or do I have to wait another hour? A sufficient growth rate is required for microbial cells before you begin harvesting or starting your main culture. A typical growth check can be performed by OD600 with your photometer.

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