WHAT IT IS
Rapid sample introduction systems are autosampler accessories for inductively coupled plasma (ICP) instruments that shorten analysis cycles and reduce carryover between samples. One widely known implementation is the FAST system, a proprietary design based on flow injection. Other manufacturers offer similar solutions under different names. All of these systems share the same goal: to improve throughput, reproducibility, and washout efficiency compared with direct autosampler aspiration.
HOW IT WORKS
Instead of continuously aspirating samples directly from the autosampler probe, the system uses a valve and loop mechanism:
Sample Loading - A defined volume is aspirated into a loop while the ICP is flushed with rinse solution.
Injection - The valve switches, introducing the looped sample as a bolus into the plasma stream.
Rinse - During analysis, the probe is already positioned at the next vial, preparing the following loop.
This overlapping process reduces idle time between samples and minimizes contamination.
ADVANTAGES
Higher Throughput: Parallel loading and analysis reduce the overall time per sample, increasing laboratory productivity.
Reduced Carryover: Efficient rinsing and loop-based injection minimize contamination from previous samples, even with high-concentration analytes.
Reproducible Volumes: Defined injection loops deliver consistent signal response across runs.
Lower Sample Consumption: Only small aliquots are required for measurement, saving material when sample availability is limited.
Flexibility Across ICP Techniques: These systems can be used with both ICP-OES and ICP-MS, making them useful for diverse applications.
CHALLENGES AND LIMITATIONS
Brand-Specific Designs: FAST and similar systems are proprietary; compatibility and features vary by manufacturer.
Maintenance Requirements: Valves, loops, and tubing need regular cleaning and replacement to prevent leaks or failures.
Clogging Risks: Samples with high dissolved solids or particulates may obstruct small channels and loops.
Additional Cost: As optional accessories, they increase overall system expense and complexity.