Spectrophotometer
Spectrophotometer - Related Videos
07:38
Introduction to the Spectrophotometer
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2023
The spectrophotometer is a routinely used instrument in scientific research. Spectrophotometry is the quantitative measurement of how much a chemical substance absorbs light by passing a beam of light through the sample using a spectrophotometer. In this video, basic concepts in spectrophotometry, including transmittance, absorbance and the Beer-Lambert Law are reviewed in addition to the components of the spectrophotometer. These concepts provide a foundation for how to determine the...
07:44
Quantification of dsDNA using the Hitachi F-7000 Fluorescence Spectrophotometer and PicoGreen Dye
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Cited by 6 •
2010
Demonstration of quantification of dsDNA using Molecular Probes PicoGreen dye and Hitachi F-7000 Fluorescence Spectrophotometer equipped with a microplate reader accessory.
10:29
Microvolume Protein Concentration Determination using the NanoDrop 2000c Spectrophotometer
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Cited by 129 •
2009
Microvolume samples are quantified by a spectrophotometer system that uses natural surface tension to retain samples without the use of cuvettes or capillaries. The dynamic range of protein concentrations and speed by which they can be measured are greatly increased with this method.
06:15
Concentration Determination of Nucleic Acids and Proteins Using the Micro-volume Bio-spec Nano Spectrophotometer
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Cited by 19 •
2011
This communication presents data on the accuracy and reproducibility of the BioSpec-nano UV-VIS spectrophotometer for dsDNA and protein quantitation. Even with ultra-small volumes (1 to 2 L), reproducibility is excellent, while the automated wiping function improves throughput and results in minimal carryover for more precise results.
03:57
Balmer Series - Student Protocol
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2020
Source: Smaa Koraym at Johns Hopkins University, MD, USA Spectral Emission Lines of Hydrogen, Helium, and NeonExpand In this experiment, you will use a spectrophotometer to measure the distinct wavelengths of light emitted in the UV and visible range by electron relaxation in hydrogen, helium, and neon. Before starting the lab, make a table in your lab notebook for the elements that you will analyze, the color of the light that you observe from the lamps, and the recorded wavelengths. Table...
FAQs
The Beer-Lambert law links measured absorbance with the amount of absorbing material, allowing a reading to be converted into an estimated concentration. This interpretation is conditional rather than automatic because the sample and measurement conditions must be appropriate. Consequently, absorbance provides a quantitative basis for comparing biological samples when those requirements are met.
The selected wavelength determines which light-absorbing characteristics are measured, so changing it can change the observed absorbance or transmission. This matters when analyzing different biological targets, including nucleic acids, proteins, pigments, or reaction-associated molecules. Wavelength selection therefore connects the optical reading to the molecule or biological process under study.
Transmission describes how much incoming light passes through the sample, whereas absorbance represents light removed from that beam. The instrument compares incoming and transmitted intensity, and absorbance is the measurement used with the Beer-Lambert law for concentration estimates. These measures describe the same optical event from complementary perspectives.
A typical measurement begins by selecting a wavelength relevant to the biological target, directing light through the sample, and comparing incoming with transmitted intensity. The result is expressed as absorbance. When the sample and measurement conditions are suitable, the Beer-Lambert law converts that optical result into an estimated concentration.
Spectrophotometer measurements can help monitor enzyme activity by tracking optical changes associated with biochemical reactions. Because the instrument quantifies light-related behavior at selected wavelengths, readings can be used to follow reaction-associated changes in biological samples. This application connects spectrophotometry with the study of enzyme function and metabolic reactions in biochemistry.
Applications span molecular biology, microbiology, biochemistry, diagnostics, and biotechnology. In these fields, measurements support nucleic acid and protein quantification, cell-growth assessment through optical density, pigment analysis, and investigation of metabolic reactions. The same optical approach therefore contributes to both basic biological research and applications that require quantitative sample characterization.