Research News from SamplePrep@UiO

Looking back into research papers on electromembrane extraction (EME), a jungle of different liquid membranes has been used, and they have been developed more or less by trial-and-error type of experiments. The last year, we have put a lot of efforts into standardizing stable and efficient liquid membranes, to propose generic extraction conditions to bases and acids of different polarity. A recent paper is one contribution in a series of papers, where we have optimized generic conditions for basic substances with low and moderate polarity

Read more…

We have for long time been investigating electromembrane extraction (EME) of peptides, in a large research project funded by the Research Council of Norway. Peptides are difficult because they have very poor partition into the liquid membrane. However, by testing a large number of liquid membrane compositions, we have learned that deep eutectic solvents show great potential. The deep eutectic solvents we prepare by mixing two solid substances together, and with a magical touch, we have a liquid that works superbly for peptide extraction!

Read more...

Generic conditions for electromembrane extraction (EME) of polar bases were developed. Now that prototype equipment is available to other research laboratories, generic conditions are highly relevant to harmonize method implementation and further development. A suitable supported liquid membrane was created by mixing 2-undecanone with deep eutectic solvents and ionic carries to extract compounds in the range -2.0 < logP < 4.5.

Read the paper... 

Nitazenes are resurfacing on the black market after more than 70 years hiding in the cupboards of drug development laboratories. These highly potent synthetic opioids are partially unregulated and generally not included in toxicology screenings. In this work, liquid-phase microextraction (LPME) was used to develop a quantitative method for rapid determination of nine nitazene analogs from whole blood.

Click here to read the paper...

Want to learn about the basics of electromembrane extraction (EME)? This tutorial discusses the fundamental theory behind EME, how the prototype equipment is constructed, common obstacles encountered with EME and walks you through some relevant applications.

Have a read if you like to get started!

Peptides are considered highly polar substances and therefore not inherently ideal for extraction in EME. Previously, this has been overcome by introducing ionic carriers into the supported liquid membrane, however at the expense of EME system stability due to high currents. This paper, for the first time, demonstrates the use of pure phosphate solvents for extraction of peptides using EME. Read more about the interesting findings in the link below.  

Read the article...

Electromembrane extraction has been considered a novel extraction technique for many years, and the lack of commercial equipment has limited its use to research laboratories. Now that commercial prototype equipment is available, the interest for routine applications is steadily increasing. This paper presents an EME method for extraction of 13 opioids from oral fluid.

Read the paper and find out how EME compared to the routine method employed at St. Olav University Hospital.

It should be easy for someone interested in EME to simply “have a go at it”. In reality, method development is often cumbersome and dependent on many factors such as analyte characteristics and extraction conditions. Finding generic extraction conditions which are applicable for a wide variety of analytes has therefore been an intensive research area at our group. This paper investigates the behavior of 96 basic substances in different extraction system to find the best generic liquid membranes for EME.

Click the link to read more…

Amphetamines are commonly used for managing ADHD and narcolepsy, but are unfortunately also the most common drugs of abuse world-wide. During synthesis, a racemic mixture is produced, where in illicit preparations, both enantiomers are present, while the most pharmacologically active enantiomer is isolated in medicinal products. This creates an avenue for identifying recreational users through the detection of both enantiomers in urine. In this work, a validated EME method was developed for the extraction of both amphetamine enantiomers and compared to the routine method used at St. Olav University Hospital. This paper is an engaging read for both newcomers and experienced EME users.

Click here to read the article...

A high-throughput method with electromembrane extraction and UHPLC-MS/MS was developed for the simultaneous determination of 20 tryptamine analogs in whole blood. Tryptamines are psychoactive substances, and may not be discovered in routine toxicology screening due to the diversity in structural analogs.  We here present a single-step green sample preparation procedure which solves this issue. 

Click here to read more...

Green chemistry and sustainability is becoming more and more important. For sure next generation scientists will give this the highest priority! Microextraction technologies are claimed to be green, but how green are they? Moreover, how green can they be, if all chemicals we use are ingredients we find in the kitchen, and all plastic consumables we use are washed in hot water and recycled? The answer you get from our latest paper published in Green Analytical Chemistry.

Read the article...

In electromembrane extraction, we transfer ionized drug molecules form a blood sample, across a liquid membrane (oil membrane) and into pure water under the influence of an electrical field. The liquid membrane is a few microliters of organic solvent. Over the years, we have learned that the chemical properties of the solvent are very important; they control the type of substances that are extracted (selectivity), and the extraction speed (kinetics). Recently, we summarized the accumulated information we have from 15 years with experiments, and discussed this in the context of molecular interactions; how molecules “talk to each other” during their travel across the liquid membrane. The fundamental understanding of this is crucial for development of new applications… 

Read more...

As analysts, we use analytical chromatography in our daily research and teaching. For many students, this ensemble of techniques may however be somewhat of a “black box” performed by an instrument that offers little-to-no clues as to how it works. In collaboration with friendly organic chemists at our department, we have therefore published a paper with a laboratory exercise that literally puts the chromatography into the hands of the students. In the exercise, students get the opportunity to pack and prepare a preparative column, mix mobile phases, load and elute compounds, and perform a visual detection, all while learning about concepts of retention mechanisms, gradient elution, and differences between preparative and analytical chromatography. Interested in reading more?

Check out the (open access) paper...

Science is continually developing and so is our understanding of how the liquid membrane in electromembrane extraction (EME) should be designed. In this overview article, we have taken a closer look into the organic solvents used as liquid membranes, and provide an update to our current understanding of the preferred properties of solvents.

Read more...

Extraction conditions for optimal performance in liquid-phase microextraction (LPME) and other extraction techniques are often based on trial-and-error experiments. By investigating the molecular interactions taking place between the analyte and the extraction system, we can build models that help us predict when an analyte is optimally extracted. In the below paper we combine existing theory on extraction kinetics and system equilibrium together with empirical data to build the fundamentals for better prediction models. We introduce the terms slow kinetics, optimal extraction window (OEW), and membrane trapping as a tool to describe the state of the extraction system. 

Read more on this topic...

In a couple of decades, all chemistry will be green chemistry. However, we are not there yet! Analytical chemistry and sample preparation will follow this trend, and will go greener! In a new paper, we define the term “Green sample preparation” for the first time, and link it to the term “green analytical chemistry”. Green sample preparation is important, because sample preparation procedures often consumes significant amounts of chemicals, reagent, solvent, and materials. In this perspective, we expect our latest collaborative paper will play an important role!

Read more…

Collaboration plays a very important role in our research. We collaborate, among others, with colleagues on our own campus (Department of Chemistry, University of Oslo), in Spain (University of Seville), and in China (Huazhong University of Science and Technology, Wuhan). In three recent papers focused on electromembrane extraction, we have investigated fundamental aspects, developed green microchip technology and investigated organ-on-chip drug metabolism, as part of this collaboration.

Read more...

Green chemistry is a hot topic, and will be extremely important for generations to come. Although the consumption of chemicals is less in analytical chemistry than in chemical industry, green analytical chemistry is still very important. To make analytical chemistry green, we need to make sample preparation green. However, how green can it be? This, we recently addressed by merging microsampling and microextraction, for determination of drugs of abuse in the forensic laboratory.

Read more about green sample preparation…

Geometry and size are highly flexible in electromembrane extraction (EME), and therefore EME is perfect with microfluidic systems. We have a strong feeling that such technology may be very important in future analytical chemistry, among others in combination with smartphone detection. However, microfluidic EME is in the early research phases, and the question remains how far development has come. In a recent paper, we answered this question together with our colleagues at the University of Copenhagen.

Read more about EME and microfluidics…

For long time, we have collaborated with scientists in China and the Czech Republic. Such collaborations are extremely important for the development of electromembrane extraction, and this research has very high priority. Below you can read three scientific papers based on recent collaboration – these works have identified new applications and developed new fundamental understanding of high importance for the future.

Read more …

Previous use of electromembrane extraction (EME) show promising results when pharmaceuticals are extracted from blood and urine samples. As EME offers advantages to traditional sample preparation, the technique has potential for routine bioanalytical measurements in the future. However, all current EME data are generated with laboratory-made equipment, as no standardized device is available. If EME is to be implemented in a routine setting, a commercially available EME device is required. In a recent paper, we tested a prototype for such device at a clinical laboratory. The device was used to extract psychoactive drugs from serum, and the developed EME-UHPLC-MS/MS method was fully validated and compared to the well-established routine method at the Department of Clinical Pharmacology at St. Olav’s University Hospital (Trondheim, Norway).

Read more about EME taking the step into clinical laboratories…

Polar or water-soluble substances are abundantly present in the human body as both drug metabolites and endogenous metabolites. To extract the few we are interested in, from biological samples, is however a challenging task with most techniques, leaving us with limited options for analyzing these substances. In this overview article, we take the temperature on current efforts to apply electromembrane extraction (EME) for efficient and selective extraction of polar compounds.

Check out the paper to see how far we have come, and where we are going…

On September 1^st, Frederik André Hansen successfully defended his PhD thesis “Electromembrane extraction of polar pharmaceutical bases and endogenous metabolites". Congratulations!

In the latest paper from our long-continued collaboration with the research group of Professor Mariá Ramos-Paýan at the University of Seville (Spain), we have developed green technology on a very small scale for the extraction of drugs from urine.

Read the paper...

We were asked to write a personal opinion on quality papers in sample preparation – this is high risk, but hopefully valuable for scientists in the field.

Read the paper...