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Temperature control is an important parameter in many UV Vis spectroscopy applications, especially for temperature-sensitive biological samples. In a new guide, we describe the importance of temperature control, with examples of common applications such as lipase activity, protein denaturation, melting point of DNA and Michaelis-Menten kinetics of beta-galactosidase.
The guide also provides detailed information about the available thermostating solutions for the METTLER TOLEDO UV/VIS Excellence spectrophotometers:
- CuveT – Single sample temperature control
- CuvetteChanger – Multi sample temperature control
1. Executive Summary
This guide describes the importance of exact temperature control for UV Vis spectroscopic measurements, with examples from common life-science applications. In addition, practical tips and hints are provided for accurate UV Vis measurements at elevated temperatures with the accessories CuveT and CuvetteChanger for the METTLER TOLEDO UV/VIS Excellence line.
2. Introduction
Thermostating in UV Vis spectroscopy generally means establishing defined temperature conditions a) before, b) during or c) after the spectroscopic measurement, as exemplified below:
a) Samples/analytes may need to be held at an exact temperature in order to delay decomposition or to provide the ideal conditions for a reaction of precursors required for a subsequent (chemical) reaction, which is then spectroscopically analyzed at the specific temperature.
b) Establish temperature conditions that are constant or change according to a defined temperature ramp protocol. Such conditions catalyze chemical reactions that need to be spectroscopically monitored.
c) Re-establish previous or different temperature conditions for subsequent spectroscopic measurements in order to monitor reversible (chemical) reactions.
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Get more information in the Thermostat UV/VIS Analysis Right Guide
3. Application Examples for Temperature-Dependent UV Vis Spectroscopy
3.1 Determination of lipase activity
Determination of lipase activity serves as an example in which temperatures elevated above ambient conditions are required in order to establish the ideal conditions for an enzyme-catalyzed chemical reaction that is to be monitored spectroscopically.
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3.2 Temperature-induced protein denaturation
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3.3 Michaelis-Menten kinetics of beta - galactosidase
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3.4 Melting temperature of DNA
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Get more information in the Thermostat UV/VIS Analysis Right Guide
4. METTLER TOLEDO CuveT Peltier Thermostating Unit
CuveT is a single cuvette thermoelectric (Peltier-based) thermostat that efficiently controls temperature in the range from 4 °C to 95 °C in UV Vis spectroscopy applications. This thermostating system can be connected to the UV7, UV5Bio and UV5 UV/VIS Excellence spectrophotometers from METTLER TOLEDO. The unit is placed on top of the spectrophotometer and no tools are required for installation.
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Get more information in the Thermostat UV/VIS Analysis Right Guide
5. Practical Tips & Hints for Thermostating with CuveT
This chapter offers practical tips and hints for routine thermostated UV/VIS spectroscopy measurements with CuveT on the basis of FAQ.
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Get more information in the Thermostat UV/VIS Analysis Right Guide
6. Thermostating with the METTLER TOLEDO CuvetteChanger
METTLER TOLEDO’s CuvetteChanger allows efficient automatic measurement of series up to 8 cuvettes for measurements with blank subtraction or complex kinetics applications. With the usage of an external thermostat it is possible to thermostat samples in cuvettes in the temperature range from 10–80 °C .
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Get more information in the Thermostat UV/VIS Analysis Right Guide
7. References
[1] www.mt.com/uv-vis
[2] www.mt.com/cuvet-peltier-uvvis
[3] Determination of Lipase Activity, Method PNAB-LIP39, Biocon Española S.A.
[4] Journal of Chemical Education, March 2000, DOI: 10.1021/ed077p 380
[5] 1. Enzyme Handbook, II, Barman, T. E., Springer- Verlag (Berlin-Heidelberg: 1969), p. 581.
