Solvent recyclers

Improving sustainability by reducing solvent use

Efficient recycling of isocratic mobile phases in HPLC and other liquid chromatographic setups may save up to 90% of solvent. Biotech Fluidics offer two options for reducing solvent consumption in liquid chromatographic instruments and related fluidic equipment.

Note that the solvent recyclers are not recommended for use in gradient applications or other setups where the composition of the fluid change during the process.

The Biotech SPR-200 Solvent Recycler is a stand-alone device, whereas the Biotech SmartSaver™ USB Solvent Recycler requires external computer control. Both solvent recycling devices operates according to similar principles and contains a three-way valve that can direct the liquid stream either to a solvent bottle for reuse or to waste, depending on the input signal and the set parameters. Distinct LEDs on the solvent recyclers indicates if it is in operation and the present position of the directional valve. The wetted materials in both devices are PEEK and PTFE making them compatible with most solvent compositions used in isocratic HPLC applications.

Operational principle

During operation the solvent recyclers continuously monitor the analogue output signal from the chromatographic detector. This data is internally converted to a digital signal that is the foundation for the automated decision making influencing the directional valve. When the signal is above the threshold, the fluid is considered contaminated and thus directed to waste (red waste outlet). When the signal is below the threshold level and the set delay time also have passed, the liquid is instead diverted to the solvent bottle (green recycle outlet).

Delay times are set to ensure that the valve switching is not occurring too early thereby avoiding accidental recycling of contaminated fluid to the solvent bottle. The default position of the switching valve is directing the fluid to waste to safeguard the recycled solvent from contamination in case of a power shortage. The solvent recycle devices can accept input signals from autosamplers to autozero the current input signal level at the time of injection.

Biotech SPR-200 Solvent Recycler

The Biotech SPR-200 Solvent Recycler is a completely stand-alone device with an integrated display to show current input and settings, and control keys to easily set its operational parameters. It is typically externally powered via 5V DC, but can also be powered and programmed via a USB connected computer running a terminal software application.

SPR-200 Solvent Recycler can reduce the mobile phase in isocratic HPLC for up to 90% by redirecting uncontaminated mobile phase into the container. The level of the input signal and setting parameters are displayed on a well-read four-digit LCD display. Valve position and the current display mode are indicated by LEDs placed next to the display. Instrument functions are operated via a membrane keyboard with six keys.

Comfortable setting of operating parameters and online device activity tracking can also be operated from a PC using any terminal application.

SPR-200 analog input accepts unipolar and bipolar signals in ranges of ± 1V or ±100 mV alternatively. Analog-to-digital converter provides data for further processing in embedded microcontroller. TTL (contact closure) input is used for the auto-zero function.

The rear panel of SPR-200 Solvent Recycler contains the detachable switching valve in the holder and connectors subpanel. The following connections are available (from the left):

Analog input (yellow)
TTL Zero input (white)
Valve connector (blue)
Micro-B USB connector (black)
Power switch (green)

SPR-200 Manual

Biotech SmartSaver™ USB Solvent Recycler

The Biotech SmartSaver™ USB Solvent Recycler is a computer-controlled device that is connected via USB cable to a personal computer running an installed software application. The USB cable also provides the power required for the Biotech SmartSaver™ USB Solvent Recycler.

SmartSaver™ USB Solvent Recycler is a device dedicated for use in isocratic HPLC. Efficient recycling of mobile phase may save up to 90% of solvent. Usually, most of the mobile phase is free of contaminants and must not be wasted. With continuous monitoring of the detector signal solvent recycler performs redirection of the uncontaminated mobile phase back to the solvent reservoir and save the solvent and waste disposal costs.

According to input signal level the 3-way valve is switched to waste or recycle position. The switching valve is connected to the detector mobile phase output. If the signal level is greater than signal threshold, the valve is switched to waste position. The back switching to recycle position is delayed with respect to time required to liquid transport from the detector cell to 3-way valve.