Dispatches from Pittcon 2018 in Orlando
Axcend: Developing portable LC required ‘entirely new mindset’
The Axcend Focus LC is a nanoflow liquid chromatograph that measures ~30x20x20cm, weighs ~5.4kg (12 lbs.) and operates on battery or electrical outlet power.
Visual or statistical output is delivered wirelessly to any Web-connected smartphone, tablet or personal computer capable of HTML5 display and it can be connected via a USB cable to a PC.
Commercial availability of the firm’s first product is slated for second quarter 2018.
The cartridge system
It was developed in the Brigham Young University laboratories of Professor Milton Lee and the technology has been licensed from BYU.
“It is a plug and play kind of unit which makes it easier for the user, they don’t have to be trained as a scientist to use this instrument,” said Dr Lee, Axcend co-founder and chief science officer.
“We have a cartridge system so you don’t have to connect the column up with wrenches and the typical way users use conventional liquid chromatography, you have a cartridge that contains a column and has on-column UV detectors that are made with light emitting diodes,” he told FoodQualityNews at Pittcon.
“It is a nanoflow system so the flow rates are around 1 microlitre per minute and so it doesn’t require large solvent reservoirs. All of the solvent we use is contained in little vials, it is internal with the instrument and you can operate for a day without changing or adding to that.”
Axcend claims the instrument requires as little as 1/500th the volumes of samples and solvents.
Designing a portable LC meant moving to 150mm (micrometer) nano-flow internal diameter capillary columns filled with 1.7mm-3.0mm fused silica particles, very small pumps and miniaturized LED UV-absorption detectors.
Making LC mini
Dr Lee said there were two major challenges with going smaller.
“When you go down to nanoflow where you are flowing such small volumes, then the connections to injector and detector are really critical. You can’t sacrifice any dead volume at all or it compromises the resolution. It has to be designed so that we don’t have any extra tubing and the connections have to be tight,” he said.
“When you go down to small columns like that you can’t use conventional UV absorption detectors so we had to design our own detector that can analyse right on the column at the end of a transparent capillary tube what the chemicals are that are moving through the system. It is two orders of magnitude more sensitive than a conventional liquid chromatograph UV absorption detector.”
A major development was the optics to focus light from an LED into a 150 micron ID capillary.
“The big problem with the change in pumping system is conventional systems pump a lot larger volume flow rates and to pump nanolitres per minute are sub microlitre per minute flow rates the pistons are really small and the pressures we need to go up to are approaching and above 10,000 PSI," said Dr Lee.
“You can position the instrument up close to the ion source of a mass spectrometer in the laboratory to get the best performance out of the LC-MS coupling.”
The injection port has a cover to stop dust and debris from getting inside.
“The cartridge has heat tape in there and there is insulation and so the column is maintained at a constant temperature even in fluctuating conditions outside,” said Dr Lee.
“As far as the performance of the instrument we’ve tried to take into consideration environmental conditions. Any time you take an instrument out of the laboratory it is harsh conditions and the instrument has to be able to perform. This instrument right now is not water-proof tight.”
‘We didn’t redefine LC; we redefined the factor to deliver it’
Axcend said anything that conventional LC is applicable to can be handled by the instrument such as food quality, spoilage and mineral content.
Individual private investors provided funding for the company.
Glen Mella, Axcend co-founder and CEO, said operators can transport the device to point of sampling, insert the column cartridge, start chemical analysis and receive LC data in an average of 10-15 minutes.
“Imagine if we were in the field trying to, with little wrenches, hook up tubes and bottles. It is just not practical,” he told us.
“Because it is portable and a small lightweight device the readers should not conclude that it is designed for lightweight usage or analyses. This does everything a liquid chromatograph does and is very robust.
“We didn’t redefine liquid chromatography we redefined the factor to deliver it. The science behind the analysis is well-established and our chromatograms that come out with the peaks defining the different molecules and compounds are going to look, for somebody experienced in chromatography, very familiar.”
Possibility to evaluate tech
Mella added it is in discussions with a branch of the military about setting up mobile labs for different types of analyses.
“We want to engage in conversations with prospective customers and partners in our space and we envision in the next 90 days engagements where it is likely people are going to want to evaluate the technology, perhaps in their own labs and work with us on a basis to design a deployment,” he said.
“So, those quickly become individual discussions with those individual entities. We’ll be releasing more on pricing in the coming weeks but it will be more affordable than traditional systems.”
When asked about capability to meet demand, Mella said: “We have those relationships in place to establish a supply chain and in our past lives have done it at other companies. While it is a start-up, it is not a start-up team. If we got an order for 1,000 units it is what we call a first class problem.
“Certain types of analyses, especially where it is a target analyte that we know what we are looking for, the self-contained UV absorption will perform the detection. For some people who have a different use case in mind and want to couple it to mass spec we can do that.
“We are one of the first devices that will output to mobile, many of the LCs are self-contained in their own PC proprietary world and you ask yourself why can’t I view that on an iPad or an iPhone and ours will.”
