The automatic sampler faces two core challenges when analyzing corrosive samples such as high salt, strong acid, and strong alkali, namely precipitation blockage and chemical corrosion. To ensure the accuracy of analysis and the durability of instruments, modern automatic samplers have developed a systematic solution through innovation in materials science and fluid design.
1、 Material Upgrade: Comprehensive Protection from Contact to Sealing
The core of dealing with corrosion is to isolate the sample pathway from easily corroded components. The key strategy is to use inert materials. For example, all components that may come into contact with the sample, such as sample bottles, injection needles, quantitative rings, tubing, and valve fittings, can be made of corrosion-resistant high-performance polymers (such as PEEK, PTFE) or ceramics. For the injection needle, special metals such as thick walled Hastelloy or titanium alloy are used, which have much higher corrosion resistance than ordinary stainless steel. Meanwhile, the sealing components have been upgraded from conventional rubber to chemically inert materials such as perfluoroether rubber to prevent swelling and aging.
2、 Fluid design: eliminate blockage and cross contamination
In response to the clogging problem caused by high salt content and easy crystallization, the automatic sampler is designed and cleaned from two aspects. The flow path design pursues simplicity and smoothness, reducing dead volume and low flow rate areas, and avoiding salt deposition. More importantly, it enhances the cleaning function. Adopting the "strong cleaning" mode, the inner and outer walls of the injection needle are repeatedly rinsed with strong solvents (such as dilute acid, hot water, or highly polar organic solvents) at high flow rates to ensure the removal of residual crystalline salts and viscous samples, effectively preventing blockage and cross contamination.
3、 Proactive maintenance and intelligent monitoring
In addition, the system software also integrates maintenance reminders and protocols, which can regularly perform flushing and passivation of the overall flow path. Some models can also monitor pressure changes and provide warnings before blockages occur, prompting users to perform maintenance.
Through this system strategy centered on material inerting and supported by flow path optimization and strong cleaning, modern automatic samplers have successfully improved their robustness in harsh analytical environments and expanded their application boundaries in fields such as environmental, pharmaceutical, and industrial monitoring.