The spectrofluorometer QuantaMaster™ from PTI can be used for many basic spectroscopic applications like the determination of the excitation and emission characteristics of a sample. The capabilities of this system can be further enhanced by using time-resolved techniques, because they will grant the following advantages:

• Decay time as further dimension enhances the accuracy of analytical measurements
• Independence from fluorophore concentration
• Discrimination of fluorescence light against elastic and Raman scattering by temporal resolution

The upgrade of a QuantaMaster™ is based on the method of Time-Correlated Single Photon Counting (TCSPC), which is considered to be the most sensitive and accurate measurement method to determine fluorescence lifetimes with picosecond accuracy. The kit further includes picosecond pulsed diode lasers or LEDs, a detector suited for photon couting, all necessary cables as well as a powerful analysis software.

The upgrade kit can in principle be directly attached to the QuantaMaster™. However, as there are some requirements that have to be fulfilled by the QuantaMaster™, e.g. a second exit port at the monochromator or a second entrance port at the sample chamber, a close cooperation is needed to propose the optimum solution. Upon request an installation as well as an extensive training on the system is also possible.

The individual components of the upgrade kit are:

Excitation The excitation subsystem consists of a common pulsed diode laser driver and different laser heads or LEDs with pulses in the picosecond time regime. The available wavelengths range from 260 nm to 1550 nm. Wavelength changes are very easy as only the corresponding head needs to be changed.

		TCSPC Data Acquisition The photon counting modules (TimeHarp 200, PicoHarp 300) contain the complete timing electronics for Time-Correlated Single Photon Counting (TCSPC) with picosecond resolution. Depending on the type of excitation source and detector, fluorescence lifetimes down to 10 picoseconds can be resolved. The data acquistion is controlled by an easy-to-use Windows™ software.

Detector The PMA-M series detector unit is recommended for the majority of applications. The unit has a built-in high voltage power supply, signal pre-amplifier and a gold plated iron housing for maximum shielding. The standard detector covers the spectral range from 185 nm to 820 nm. Other spectral ranges as well as other detector types are also possible.

		Software The FluoFit program is a multiexponential fluorescence decay fitting software for PCs. It implements an iterative reconvolution of the instrument response and the observed fluorescence decay with nonlinear error minimization. Up to four-exponential decay models or different lifetime distribution models can be fitted to the observed data. IRF and decay background as well as time shift are included as fit parameters. Anisotropy analysis and advanced error analysis with different methods is also possible. Global analysis is possible for all included models.