Cuvette

A cuvette used in a dye laser.
A disposable, plastic cuvette.

A cuvette is a small tube of circular or square cross section, sealed at one end, made of plastic, glass, or fused quartz (for UV light) and designed to hold samples for spectroscopic experiments. The best cuvettes are as clear as possible, without impurities that might affect a spectroscopic reading. Like a test tube, a cuvette may be open to the atmosphere on top or have a cap to seal it shut. Parafilm can also be used to seal it.

Inexpensive cuvettes are round and look similar to test tubes. Disposable plastic cuvettes are often used in fast spectroscopic assays, where speed is more important than high accuracy.

Some cuvettes will be clear only on opposite sides, so that they pass a single beam of light through that pair of sides; often the unclear sides have ridges or are rough to allow easy handling. Cuvettes to be used in fluorescence spectroscopy[1] must be clear on all four sides because fluorescence is measured at a right-angle to the beam path to limit contributions from beam itself. Some cuvettes, known as tandem cuvettes, have a glass barrier that extends 2/3 up inside, so that measurements can be taken with two solutions separated, and again when they are mixed. Typically, cuvettes are 1 cm (0.39 in) across, to allow for easy calculations of coefficients of absorption.

Cuvettes to be used in circular dichroism[2] experiments should never be mechanically stressed, as the stress will induce birefringence[3] in the quartz and affect the measurements made.

Types of cuvettes

There are three different types of cuvettes commonly used, with different usable wavelengths:

and a matching tolerance of 1% at 220 nm

  • ES Quartz has a usable wavelength range of 190 to 2,000 nm,

and a matching tolerance of 1% at 200 nm

  • IR Quartz has a usable wavelength range of 220 to 3,500 nm,

and a matching tolerance of 1% at 2,730 nm

Specialized cuvettes

Diagram of DiluCellTM. Reduction of the pathlength (d) results in automatic dilution of the sample by factor 10 or 20.

The Lambert-Beer-Law[5] empirically relates the absorption of light to the properties of the sample. The law states that there is a logarithmic dependence between the transmission of light through a specific sample (T = I/Io with I = outgoing light and Io = incoming light), the molar extinction coefficient for a specific compound (ε), the concentration of the absorbing species in the material (c) and the distance the light travels (d).

log (Io/I) = ε x c x d

By leaving all conditions constant but changing the pathlength (d, distance the light travels), you can bend the Beer-Law to get an automatic dilution of your sample. This principle is realized within a specialized cuvette, the DiluCellTM[6] [7]. Reduction of the pathlength from 10 mm (standard cuvette) to 0.5 mm (DiluCell 20) or 1.0 mm (DiluCell 20) results in an automatic dilution of the sample by factor 20 (DiluCell 20) or factor 10 (DiluCell 10). Manual dilution steps can be avoided. This saves time, excludes dilution errors and cross contaminations making DiluCell™ ideal for GLP. In addition, reduction of the pathlength enables spectrophotometeric measurements with minimal volumes of 100 µl (DiluCell 20) and 200 µl (DiluCell 10).


References

  1. ^ "An Introduction to Fluorescence Spectroscopy", http://www.bioch.ox.ac.uk/aspsite/services/equipmentbooking/biophysics/introfluor.pdf, Perkin Elmer Inc. 2006
  2. ^ "Circular Dichroism (CD) Spectroscopy", http://www.bioch.ox.ac.uk/aspsite/services/equipmentbooking/biophysics/introfluor.pdf, Applied Photophysics Ltd., 2011
  3. ^ Weisstein, Eric, W. "Birefringence" http://scienceworld.wolfram.com/physics/Birefringence.html, scienceworld.wolfram.com, Wolfram Research, 1996-2007
  4. ^ "Quartz Glass: UV Quality Fused Silica", http://www.pgo-online.com/intl/katalog/quartz_glass.html, prazisions glas&optik
  5. ^ "Beer's Law" http://teaching.shu.ac.uk/hwb/chemistry/tutorials/molspec/beers1.htm, Sheffield Hallam University.
  6. ^ OD600 DiluPhotometer™ und SERVA SingleQuant Assay - Alternativmethode zur Colorimetrischen Protein Quantifizierung Dr. Judith Koch, Dr. Susanne Manetto, Dr. Jürgen Dreher, Dr. Andrea Huber
  7. ^ DiluCell information sheet, http://www.implen.de/downloads/DiluCell_Data_Sheet.pdf

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Look at other dictionaries:

  • cuvette — [ kyvɛt ] n. f. • XIIe; de cuve 1 ♦ (1680) Récipient portatif large, peu profond, qui sert principalement à la toilette, à la vaisselle, à la lessive. ⇒ bassine. Une cuvette en plastique. 2 ♦ Partie d un lavabo, des W. C. qui contient l eau. ♢… …   Encyclopédie Universelle

  • Cuvette — Basisdaten Hauptstadt: Owando Fläche: 46.060 km² …   Deutsch Wikipedia

  • Cuvette — Saltar a navegación, búsqueda Cuvette es una de las 10 regiones de la República del Congo. Se encuentra en la parte central del país. Rodeada por las regiones de Cuvette Oeste, Likouala, Plateaux, y Sangha, y por la República Democrática del… …   Wikipedia Español

  • Cuvette — Cu*vette (k? w?t ), n. [F., dim. of cuve a tub.] [1913 Webster] 1. A pot, bucket, or basin, in which molten plate glass is carried from the melting pot to the casting table. [1913 Webster] 2. (Fort.) A cunette. 3. (Spectrometry) (Analytical… …   The Collaborative International Dictionary of English

  • cuvette — CUVETTE. s. f. Petite cuve. Il se dit ordinairement d Un vase dont on se sert pour se laver les mains, ou pour d autres usages. Cuvette de cuivre. Cuvette d argent. Cuvette de marbre …   Dictionnaire de l'Académie Française 1798

  • Cuvette — (fr., spr. Küwett), 1) Sammelkasten an metallenen Dachrinnen, aus denen das Regenwasser durch die Fallröhren abfließt; 2) etwa 10 Fuß breiter, 6–8 Fuß tiefer Abzugsgraben in den trockenen Gräben der Festungen, um das Regen u. Quellwasser von dem… …   Pierer's Universal-Lexikon

  • Cuvette — (franz., spr. küwett), s. Küvette …   Meyers Großes Konversations-Lexikon

  • Cuvette — (frz. Küwätt), dasselbe was Cunette …   Herders Conversations-Lexikon

  • cuvette — Cuvette. s. f. Petite cuve. Il se dit ordinairement de celles qu on met dans les sales où l on mange, pour y jetter l eau dont on s est lavé les mains, & les rinceures des verres. Cuvete de cuivre. cuvete d argent. cuvete de pierre, de marbre …   Dictionnaire de l'Académie française

  • cuvette — [kyo͞o vet′] n. [Fr, basin, dim. of cuve, vat < L cupa, tub: see CUP] a small glass tube used in spectrometry and photometry …   English World dictionary

  • cuvette — /kooh vet , kyooh /, n. 1. Also, curvette. Also called chevee. a gemstone with a raised, cameolike figure or design carved on its hollowed surface. 2. Chem. a tube or vessel used in laboratory experimentation. [1670 80; < F, dim. of cuve vat L… …   Universalium


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