Ricerc@Sapienza

The required instrument is a High-Performance Liquid Chromatography system developed to operate in both analytical and preparative modes, in ultra-fast, fast, and conventional chromatography, and using columns with a particle size of 1.8 microns. The chromatographic system consists of several units and accessories that compose a versatile and high-performance instrument for the qualitative and quantitative analysis of complex mixtures and for the purification of large amounts of samples. The units described below compose the instrument. - Two isocratic pump modules with operative pressures settable up to 500 bar (50MPa) and operative fluxes ranging from 0.5 ml/min to 20.00 ml/min, with steps of 0.001ml/min to ensure the maximum stability and accuracy of solvent pumping, equipped with two ceramic pistons with automatic backwashing, double check-valve, the purge valve and manual switch valve for two solvent (for washing/regeneration). Robust isocratic pumps allow the use of several different organic solvents, polar and nonpolar, as well as aqueous solvents, to operate both in direct and reverse phase and in HILIC mode. - An analytical manual sample injector including a 20 microliter sample loop and a contact switch for analytical start synchronization. It can be equipped with a sample loop of 20 µl. - A preparative HPLC manual sample injector including a 500 µl sample loop and a contact switch for analytical start synchronization. - A spectrophotometric UV-visible detector with a double wavelength in the range of 190-900 nm with automatic control under microprocessor and display for parameters visualization also during the run, with frontal entrance, an optical path length of 10 mm, a volume of 17 microliters and an automatic recognition with conical shape for minimizing the baseline variations due to mobile phase composition changes. - An analytical UV-visible diode array detector (DAD), which incorporates elements with 1024 photodiodes for a high spectral resolution in the wavelength range of 190 - 900 nm. This detector has a temperature control system for the analytical flow cell and the lamp, allowing a stable baseline and the best performance in terms of noise and drift. Indeed, the presence of a mercury vapor lamp provides the automatic calibration of wavelength. Finally, frontal access to the flow cell and lamp is a plus for the maintenance of the detector. - A differential refractive index detector (RID) for operating in analytical mode up to 10 ml/min or in preparative mode up to 120 ml/min. A specific design of the reference prism and measurement cells, with a thermostatic system, allows for high performances in terms of baseline stability and sensitivity. This detector can also be used without external software, taking advantage of the internal software and input devices, which permit the setup of of programs with 64 steps and with 0.1 min of the resolution; this also allows the automatic solvent mixture changes in the reference cell and the measurement range modification. Analytical and preparative cells can be used for the refractive index detector. - An Evaporative Light Scattering Detector (ELSD) with gas flow control technology to ensure optimal performance at room temperature. This feature allows to considerably reduce the time of mobile phase evaporation by adding a dry gas, which decreases the relative humidity of the gas inside the pipe, providing the evaporation cycle at low temperatures. The outcome is a chromatographic separation with minimum peak dispersion and high resolution. When using non-volatile solvents, temperature can be increased up to 100 °C with a large application field. The ELSD is ideal for non-volatile organic compounds without or with weak UV chromophores, that cannot be analysed by the previously described detectors, such as some natural compounds, surfactants, sugars, polymers, additives, lipids, and steroids with boiling points under 100 °C. - A personal computer including a Software package and data acquisition board/interface for the control of the instrument units and acquired data and microfluidic connections for both analytical and preparative modes.