WHAT IT IS
Autosampling in inductively coupled plasma (ICP) spectrometry refers to the automated introduction of liquid samples from a rack of vials or well plates into the instrument. Instead of manual pipetting, an autosampler robotically moves a probe to each container, aspirates a defined volume, and delivers it to the plasma through the sample introduction system. Autosampling is standard in both ICP-OES and ICP-MS, supporting routine workflows, high-throughput laboratories, and applications that require reproducibility and minimal operator intervention.
HOW IT WORKS
An autosampler typically consists of a sample tray, a robotic arm with a probe or needle, a peristaltic pump, and control software. The process follows a cycle:
Probe Positioning - The robotic arm moves the probe to the selected vial.
Sample Aspiration - The peristaltic pump draws a defined volume of liquid into the sample tubing.
Sample Delivery - The aspirated liquid is carried into the nebulizer, where it is converted into an aerosol and introduced into the ICP torch.
Rinsing - Between samples, the probe is dipped into a rinse solution to remove carryover.
Advanced autosamplers may include temperature-controlled racks, barcode identification, rapid introduction systems, or integrated dilution functions.
ADVANTAGES
Automation of Workflows: Reduces manual handling and operator error, improving reproducibility.
High Throughput: Capable of processing dozens to hundreds of samples sequentially with minimal supervision.
Consistent Sample Delivery: Provides stable aspiration rates and volumes, enhancing data quality.
Integration with Accessories: Compatible with rapid sample introduction systems, fraction collectors, and online pre-treatment modules.
Sample Protection: Options such as cooling racks help preserve volatile or thermally sensitive analytes.
CHALLENGES AND LIMITATIONS
Maintenance Needs: Probes, pumps, and tubing require regular cleaning and replacement to prevent contamination or leaks.
Carryover Risks: Incomplete rinsing may transfer residues between samples, especially in high-matrix solutions.
Clogging Sensitivity: Particulate-rich or viscous samples can obstruct probes and tubing.
Added Cost and Complexity: Autosamplers increase the price of ICP systems and introduce more components requiring calibration and service.
Space and Setup: Large autosamplers take up bench space and require careful integration with the ICP instrument.
See instruments related to this term in the database