With the MultiVap concentrators of LabTech, based in Italy, it is possible to evaporate solutions to solid state or a fixed end-point volume without the use of vacuum and high temperature. During the operation, these instruments accelerate the evaporation of the solvent by decreasing its partial vapor pressure just above the surface of the liquid. The MultiVap concentrators use blowdown technique to remove the gas layer that is saturated with the solvent vapor. Because the inert gas stream seizes the solvent molecules that pass into the gas phase, they cannot return into the liquid phase. The removed particles may be replaced by newer and newer solvent molecules, thus increasing the rate of evaporation. The blowdown technique is excellent for evaporating smaller sample volumes between 2 and 200 ml. With higher volumes, there is a risk of loss of volatile components due to the longer concentration time. In LabTech sample evaporators, the evaporators are housed in a temperature-controlled water bath or aluminum block, even in this way increasing the rate of concentration.
MultiVap 54 – 54-position automated sample concentrator
The MultiVap 54 evaporator with 54 sample positions deserves special attention not only for its shape but also for its great technical solutions. Beside the water bath heating and the easy-to-replace various test tube holders, the MultiVap54’s special feature is that its nozzles are mounted on a motor-driven head. The programmability of the nozzle blowing height allows the constant distance of the nozzles from the surface during evaporation while the amount of liquid decreases. Thus, the gas flow reaches the surface of the solution always from the same distance, there is no need to continuously increase the gas flow, which can mean significant savings in the laboratories where the exhaust gas is supplied from a gas cylinder. The economical operation is also aided by the fact that the nozzles are arranged in six rows, while the gas flow can be switched in rows and the unused positions in one row can be blinded with a nozzle cap. To set the optimal position of the nozzles, their lateral position can be adjusted manually row by row. To monitor the effect of evaporation and gas flow (avoiding splashing), the water bath has a backlight and a transparent window. Due to the built-in drain the replacement and cleaning of the tank can be done easily.
The instrument is controlled by a touch screen control unit, which can be used to set and saved as methods the gas pressure, the temperature, the tube height, the time and head movement parameters. The memory of the instrument is able to store up to 500 methods.
The removal of the generated solvent vapors from the instrument is ensured by a built-in extraction system. To drain the vapors, the instrument must be placed in a fume hood or the approximately 3-meter-long hose must be connected to the laboratory exhaust system.
- temperature range: from room temperature to 99 °C
- required gas pressure: 2-7 bar
- gas flow per nozzle max 2.6 liter/minute
- dimensions: 50 x 50 x 69 cm (W x D x H), 34 kg