Markes launches sample preparation and concentration platform

The platform, called Centri, uses robotics to automate sampling and pre-concentration of volatile and semi-volatile organic compounds (VOCs and SVOCs). VOCs give rise to aroma and are fundamental in making food enjoyable to eat.

Sample introduction modes are HiSorb high-capacity sorptive extraction, headspace, headspace-trap, solid-phase micro-extraction (SPME), SPME-trap and thermal desorption.

Analyte flows from all modes can then be concentrated on a sorbent-packed cryogen-free focusing trap, using the same technology found in Markes’ thermal desorption (TD) instruments.

Boost productivity for GC–MS sample preparation​​

Sampling vapours onto sorbent tubes with analysis by TD is used for food aroma profiling and off-odour detection.

Markes’ technical marketing director, Dr Massimo Santoro, told us it enhances productivity for GC–MS sample preparation and pre-concentration of solid, liquid and gaseous samples.

The automated HiSorb capability is for those in the food and environmental sectors where reliable analysis of aqueous samples, soils and solids in general are key areas of interest, he added.

The product, launched at Analytica 2018 in Munich, can be used for food and beverage as front-end to GC-MS(MS) analysis.

Dr Santoro said automation is central to appeal of the instrument as well as the trap and valve technology.

“The use of robotics for all operations makes Centri ideal for many laboratories, especially those who are currently struggling with time-consuming manual sample preparation techniques, such as liquid–liquid extraction and solid-phase extraction,” ​he said.​

“As well as enabling ppt-level sensitivity and allowing selective purging of interferents such as water and solvents, the trap and valve design used in Centri allows samples to be split and re-collected onto a clean sorbent tube – a technology that we pioneered at Markes 20 years ago. ​

“It’s said that time is money, and this is especially true in modern analytical laboratories, where even modest improvements in sample throughput can make major differences in revenue.​ With Centri, you can set up a complex sequence of runs for a variety of samples and injection modes, and then literally walk away to get on with other tasks.”​

Matrix interference​

Many analysts value re-collection because it allows a sample to be analysed multiple times, said Dr Santoro.

“This approach brings numerous benefits to Centri now - for example, reduced need to carry out lengthy sample extraction steps to repeat an analysis, greater peace-of-mind by storage of valuable samples, analysis of a wider concentration range by changing the split flow ratios, and easy validation of complete analyte transfer.”​
The platform offers the ability to automate high-capacity sorptive extraction from liquids and solids using Markes’ HiSorb probes.

By using a relatively large volume of PDMS sorbent fixed on an inert metal probe, HiSorb allows high sensitivity and robustness to matrix interferences.
Centri can desorb industry-standard thermal desorption tubes in compliance with standard methods.

These tubes can be packed with sorbents and used with pumped, diffusive or dynamic-headspace sampling or used to contain small samples of materials and foods that are then desorbed directly.