In our regular series we break down our favourite recent news and research from academic and trade journals- a collection of what you need to know and what has simply caught our eye. In this edition we examine the role IR plays in preventing malaria, identifying lethal contaminants in recreational drugs, the ability to better understand the additives / nutritional content in food and (our personal favourite) in advancing the understanding of Saturn and other gas-giants of the solar system.

1) mid IR’s role in the fight against malaria

According to WHO figures, in 2016 alone malaria killed 445,000 people. And there is concern by those trying to prevent the deaths that current measures are no longer working as effectively as they once did. In the WHO’s 2017 World Malaria Report, the organisation’s director general points to “a troubling shift in the trajectory of this disease.” With less than half of countries with ongoing transmission being on track to reach critical targets for reductions in the death and disease caused by malaria. “Progress appeared to have stalled.” As outlined in a 2016 Lancet paper, led by Janet Hemingway of the Liverpool School of Tropical Medicine, insecticide resistance among Anopheles mosquitoes, which are vectors for the disease, is a primary concern in fighting malaria.

It is known that Anopheles must survive for at least 10 days to possibly transmit malaria. It is therefore vital to monitor and accurately estimate both the size and age distribution of mosquito populations when evaluating malaria vector control interventions. This month saw the publication of a rather interesting approach led by researchers at the University of Glasgow using a combination of mid-IR spectroscopy coupled with machine learning. The research paper states that using this approach, they can identify both the species and age of females of the African malaria vector species Anopheles gambiae and An. arabiensis with an initial accuracy of over 80%.

The method doesn’t require highly trained personnel, has “a negligible cost per mosquito” and can be easily applied in both lab and field settings. The researchers are now looking to improve accuracy and expand the methods to additional species through the collection of larger mid-infrared spectroscopy data sets.

Fig: Typical near- (left, blue), mid- (centre, green), and far-infrared (right, pink) spectra of an An. gambiae mosquito taken from Gonzalez, Babayan et al’s paper Prediction of mosquito species and population age structure using mid-infrared spectroscopy and supervised machine learning, published in Wellcome Open Research

2) Detecting lethal cutting agents in illegal drugs

Towards the end of May, the US Customs and Border Protection (CBP) force made a routine stop of a trailer thought to be carrying a commercial shipment of carrots from Mexico into Texas. In doing so they intercepted a “huge” load of methamphetamine bound for the US – 384 packages totaling 929 lb of the drug, worth $18.5 million (£14.7m).  

It’s been well reported that the US is currently in the grips of an opioid epidemic, with more than 47,000 people dying each year from overdoses, and this number has now surpassed both automobile and firearm accidents as the leading cause of accidental death.

Whether it’s in crystal meth, cocaine or opioids, one of the largest causes of death and hospitalisation is the use of cutting agents, which either dilute the supply to raise profits or increase the drug’s potency. For example, the most-used additive found in cocaine, phenacetin, increases risk of cancer and kidney damage. The second, levamisole, is a veterinary pharmaceutical used to deworm livestock; and when mixed with cocaine, it can rot flesh.

It is known that the purity of substances varies significantly depending on the region of seizure. For example, the purity of seized heroin in United States, Thailand, Europe, Australia ranges from 13.5% to 98%, and for cocaine purity has fluctuated between 6.2% and 98% for these regions. For amphetamines and methamphetamines, data collected in the same countries has shown fluctuation from 1% to 44%.

A May 2019 publication in the Journal of Forensic Sciences highlights that common methodologies for analysis and standard reporting practices frequently do not include cutting agents, resulting in lacking or inadequate information regarding the prevalence of these substances.

And as in pharmaceutical counterfeiting, the use of mid and near-infrared sensors gives the ability to analyse a chemical structure in a simple portable way that enables rapid identification and policing of adulterants used and sentences set to better take these into account.

3) Understanding Saturn

Cassini may have first flown past Saturn over 13 years ago, and last gave photos of the planet in 2017, but the IR images it captured are still giving valuable information to scientists seeking to better understand the planet’s composition.

Vast storms in the upper atmosphere of gas giant planets can contain material swept up from much lower in the atmosphere. Researchers at University College London and the University of Arizona have now applied a “deep learning” approach to IR images from Cassini to detect these storms on Saturn.

Writing in the journal Nature Astronomy, and publishing at the end of April, the team explains the results from the first demonstration of their PlanetNet algorithm and shows how dark storm clouds in the upper atmosphere contain material swept up from the lower atmosphere by strong vertical winds. The PlanetNet algorithm was trained and tested using infrared data from Cassini’s VIMS instrument.

4) Mid-IR’s role in detecting and managing the levels of nano/micro plastic pollution in the environment

We’ve written several times that as biofuel technologies advance, the need to identify the source of them increases significantly.

Several forms of biofuel – notably palm oil – can be as destructive to the environment as crude oil. Especially as they either require the cutting down of rainforests or replacing food crops.

Fig: while next gen biofuels can be almost carbon neutral, the production of several forms is more polluting than crude oil. Testing is therefore essential if the transport industry is to meet its climate change commitments

While much of our writing has focused on the shift to algal forms, which can be grown in industrial processes, a Spectroscopy Now article from May caught our eye for a very different problem.

As the article points out: glycerol can be used as a biofuel and one of the more recent plants that is being exploited is the purging nut, a drought-resistant perennial bush whose seeds have a high oil content. The resulting oil is also being adopted by the medical products sector for use in dermal implants and wound dressings among other applications.

However, it has recently been shown that glycerol from the purging nut is susceptible to contamination from phorbol esters, which are tumor promoting chemicals.

There are several mass spectrometric methods for detecting phorbol esters in complex matrices, generally involving multi step sample pretreatment followed by LC/MS. Now, a group of scientists has offered an alternative using a portable spectrometer that could be used for the rapid testing of samples in the field.

Near- and mid-IR spectroscopy has proven to be a powerful tool in enabling the rapid analysis of substances – from biofuels to medicines to food – and can be cost-effectively designed into portable lightweight testing systems. See our white paper on the principles and considerations behind creating such a system.

5) Testing the nutritional content of pasta sauces

As we highlighted in our 2018 article on food contamination, one of the big problems with food manufacturing is the complexity. It has led to the horse meat scandal in the UK, and over in the US the Guardian newspaper is currently running a series called Toxic America on food additives / pesticides that have been banned around the world but are legal in America.

To quote their May 2019 article on bread: “Give us this day our daily foam expander. It may sound odd, but in America, your loaf of bread can contain ingredients with industrial applications – additives that also appear in things like yoga mats, pesticides, hair straighteners, explosives and petroleum products.”

Earlier this month a rather wonderful paper appeared in the journal Molecules looking at how handheld IR spectroscopy is set to become the technique of choice for food and drink testing and have used such spectroscopy devices to not just detect ingredients but determine the nutritional parameters of pasta and sauce blends.