An open source 3D printed autosampler for capillary electrophoresis

Area of Science:

• Analytical Chemistry
• Instrumentation Science

Background:

• In-house built capillary electrophoresis (CE) systems often rely on manual sample injection, leading to low precision and requiring skilled operators.
• Existing automated samplers are limited, often processing only one sample at a time and necessitating manual intervention for multiple sample analyses.

Purpose of the Study:

• To develop and construct a fully automated, open-source autosampler for capillary electrophoresis (CE).
• To create a modular component for in-house built CE instruments, capable of handling multiple samples autonomously.

Main Methods:

• Designed and 3D printed an inexpensive autosampler comprising an injection unit with a sample carousel and a flushing unit with a miniature pump.
• Utilized an Arduino Mega microcontroller and custom Arduino code for autonomous operation, including programmable injection sequences.
• Integrated a keypad and LCD for user input of injection sequences.

Main Results:

• Developed a 3D-printed, open-source autosampler for CE, capable of autonomously injecting up to 14 samples.
• Achieved excellent injection repeatability with less than 2.7% RSD for peak areas.
• Demonstrated successful performance with two different CE systems: one with contactless conductivity detection (C4D) and another with laser-induced fluorescence (LIF) detection.

Conclusions:

• The novel, Arduino-based autosampler provides a missing instrumental sampling solution for laboratory-made CE instruments.
• The open-source design allows for easy construction in any laboratory, offering a time-saving add-on for modular CE systems.
• The autosampler enables autonomous hydrodynamic injection with programmable sequences, capillary flushing, and control over high voltage and data acquisition.