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How to Choose Your Autosamplers

How to choose an autosampler to boost automation and research efficiency

by
Andy Tay, PhD

Andy Tay, PhD is a freelance science writer based in Singapore. He can be reached at andy.csm2012@gmail.com.

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One of the key goals of the industrial 4.0 revolution is using automation to boost productivity and output. Autosamplers are devices that provide automated sample injection or extraction to an analytical instrument. The amount and rate of sample exchange can also be programmed according to the applications. Autosamplers are increasingly being used by industry to improve the speed, precision, and accuracy of sample processing and analysis. Here, we will discuss some common types of autosamplers and their applications, as well as provide readers with some guidelines when purchasing autosamplers.

Autosamplers to enhance analyses

Autosamplers are commonly used to transport solid samples for weighing and analysis. For instance, solid phase microextraction (SPME) is a powerful method to identify trace components in solid samples. Autosamplers have been integrated with SPME for automated and uniform heating of solid samples to extract gaseous organics with a fiber before further analysis with gas chromatography. This procedure provides more reproducible data than human manual sampling. 

Autosamplers are extensively used to sample and deliver liquid samples of small volumes, even down to tens of microliters. The device is usually connected to a remote pumping syringe via tubing to extract and expel liquids. Common applications include using autosamplers in titration, liquid chromatography, and water analysis to measure the content of carbon, inorganics, and nutrients in water samples. 

It is important to consider whether there is scale and experimental needs to support the purchase decision.

The autosampler design for gases is like that of liquid samplers, except they are connected to a pump that continually sucks out or expels gas mixture into an analytical device like a gas chromatograph.

Considerations

While autosamplers can enhance lab productivity, they often come at a heavy price tag. Hence, it is important to consider whether there is scale and experimental needs to support the purchase decision. Autosamplers are typically used in high-throughput labs handling thousands of samples per day with low sample variance, such as in diagnostics labs, to boost efficiency and minimize human error. For instance, autosamplers were used by public health agencies around the world to periodically collect wastewater samples for SARS-CoV-2 surveillance.

Autosamplers offer different precision levels and throughputs, so users should choose a model that best meets their needs. For instance, most liquid autosamplers can handle between 10 to a few hundred samples, and most are programmed to self-align inlet and sample positions to prevent sample loss. Users may also want to consider liquid autosamplers that offer flexible volume injection from tens of nL to 500-1000 µL to expand the range of applications. 

While the concept of autosamplers is easy to understand and similar across different models, many manufacturers are selling autosamplers as optional parts that are incompatible with devices from their competitors. This makes it challenging for users because they would likely need to purchase the autosamplers from the same company that makes their analytical devices. There have been some efforts to create open-source programming scripts to improve the compatibility of autosamplers across various brands of analytical equipment, but this is not easy because not all labs have programming capabilities. Thus, users should check if their current analytical devices are compatible with the autosamplers they want to purchase.

The use of autosamplers is becoming more common in industry and even labs working in diagnostics and high throughput screening that need to analyze a large number of samples efficiently with little room for error. When chosen wisely, autosamplers can make a huge difference to lab productivity.