ETH, Laboratory of Organic Chemistry, Zurich, Switzerland

Q: WHAT IS THE FOCUS OF YOUR LAB’S RESEARCH?

A: Our laboratory focuses on the development of small molecules with functions that are fulfilled in nature by large macromolecules. We utilize the power of organic synthesis to access functionalities that nature might not have in the repertoire of building blocks. The focus is both on practical applications and an understanding of the properties on the molecular level. This scope includes the development of bioinspired asymmetric catalysts and functionalisable collagen, molecular scaffolds for applications in supramolecular and biological chemistry (e.g., cell-penetrating peptides and tumor targeting) and the controlled formation of metal nanoparticles.

Q: WHAT WAS YOUR PREVIOUS WORKFLOW OR CHALLENGES?

A: For the synthesis of building blocks and target molecules it is important to efficiently analyze and confirm their chemical structures. We routinely do this by, e.g., NMR spectroscopic analysis of the isolated and purified products. This involves the analysis of small molecules in our asymmetric catalysis projects as well as molecules with molecular weights of up to 2000 Da in our chemical biology and materials science projects. In particular for new reactions, fast and straightforward analysis methods for the newly formed compounds are important but challenging at the same time.

Q: WHY DID YOU INCORPORATE THE EXPRESSION® CMS INTO YOUR LABORATORY?

A: The expression® CMS allows us to efficiently analyze the mass of newly formed compounds in (almost) real time. We particularly value that the instrument allows us to monitor the reaction progress of crude mixtures. Separated on a TLC, products and potential side products can be identified, which results in an optimized and faster down-stream-processing, e.g. column chromatography, and only desired products are isolated on a preparative scale. Furthermore, the ASAP mode is very helpful and extremely fast, when looking for expected product masses, e.g. in the fractions of preparative HPLC separations – just dip it in and measure the MS… it takes 30 seconds per fraction. The possibility to easily switch between the ionization modes ESI and APCI as well to measure MS spectra in positive and negative mode in parallel is very helpful for a fast and reliable analysis.

Q: WHO WOULD YOU RECOMMEND TO PURCHASE THE EXPRESSION® CMS?

A:  We recommend the expression® CMS in combination with the TLC-Reader Plate Express™ to any group working in the field of synthetic organic chemistry. The reliable and fast identification of molecules is extremely helpful to monitor reactions, to identify the desired products and potential side products, and to simplify downstream processing.

Simple LC/MS Analysis of Carbohydrates

Introduction

There are many separation and detection methods that are available for the determination of saccharides. These include GC-MS with derivatization, HPLC-UV with derivatization, HPAEC-PAD (High-performance anion-exchange chromatography coupled with pulsed amperometric detection), and LC-MS. The availability of a sensitive and accurate method is still a challenge. For an LC-MS method, given the high polarity, hydrophilicity and low proton affinity of these compounds, it can be difficult to ionize them directly by electrospray by ESI or APCI. The chemical diversity and numerous isomers of carbohydrates further complicates their analysis with LC-MS.

In this Application Note, post-column chloride attachment is used for the analysis of samples containing carbohydrates using the Advion expression® Compact Mass spectrometer (CMS). The 35Cl and 37Cl isotopes also provide confirmation for the formation of the chloride adducts in negative ion APCI mode. Four carbohydrates (Fructose, Glucose, Sucrose and Lactose) are used for method verification.

Urinary Cortisol Quantitation Using Ultra High Pressure Liquid Chromatography/Compact Mass Spectrometry

Introduction

Cortisol is an important steroid hormone produced from cholesterol in the adrenal cortex. Its secretion is closely regulated by the Adrenocorticotropic hormone (ACTH). Most cortisol is protein-bound and only unbound cortisol is excreted in urine. The measurement of cortisol in urine is typically used to diagnosis of Cushing’s syndrome, a disorder of hypercortisolism.

Although immunoassay methods have extremely high sensitivity, they are subject to variable interferences from other steroids and their conjugates. Liquid chromatography with tandem mass spectrometry is used in clinical analysis because of its higher specificity and selectivity than immunoassay methods.

A simple and robust UHPLC/MS method using the Advion Interchim Scientific expression® Compact Mass Spectrometer (CMS) is introduced for urinary cortisol analysis and the dynamic range and sensitivity (LOD and LLOQ) of the UHPLC/CMS method will be evaluated.

Eberhard Karls University, Institute of Pharmaceutical Sciences, Tübingen, Germany

 

Q: WHAT IS THE FOCUS OF YOUR LAB’S RESEARCH?

A: We are a Medicinal Chemistry laboratory with a major focus on kinase inhibitors. Within the last decade, we have developed highly potent and selective chemical probes such as Skepinone L, a specific p38 MAP kinase inhibitor suitable for in vivo use. Our strategies involve the reversible targeting of kinases via ATP-competitive type I or less competitive type II inhibitors as well as intermediate type 11/2 inhibitors. More recently, we turned towards covalent kinase targeting by addressing non-catalytic cysteines. This strategy furnished excellent probes for JNK3 and JAK3. For example, we developed FM-381, an extremely isoform-selective JAK3 inhibitor, which is now available as a high-quality probe from the Chemical Probes Portal and the chemical probes program of the Structural Genomics Consortium.

Q: WHAT WAS YOUR PREVIOUS WORK EXPERIENCE?

A: Since our work mainly relies on organic synthesis, we have an urgent need for accurate and rapid characterization of novel compounds. While our group owns two NMR spectrometers and several HPLC systems, mass spectrometry was usually done at a shared service unit, which caused additional costs and delays. Although we were also equipped with several LC-MS devices, these were routinely used for biological samples or metabolism studies, thus adapting the workflows for chemical samples was always tedious. Consequently, a more practical solution was required.

Q: WHY DID YOU INCORPORATE THE EXPRESSION CMS INTO YOUR LABORATORY?

A: As mentioned, mass spectrometry was one of the bottlenecks in our synthesis endeavors. The purchase of an LC-MS system exclusively for reaction monitoring and compound analysis would have been an option. However, especially when dealing with crude mixtures, LC-MS devices are typically quite vulnerable and require a lot of maintenance. Moreover, if you do not have a UPLC system, LC-MS runs are time-consuming, limiting the number of samples to a maximum of a few dozens a day, which is a serious problem with respect to the size of our group.

Therefore, Advion’s expression CMS in combination with the Plate Express™ TLC plate reader was the perfect solution for us. It is easy to use, quite robust, offers a high throughput, and is suitable for almost the entire mass range of our compounds. Needless to say, the device is especially suited for reaction monitoring and the rapid assignment of product fractions from column chromatography.

Q: TO WHOM WOULD YOU RECOMMEND THE EXPRESSION CMS?

A: The expression CMS/Plate Express™ couple can be recommended to Organic or Medicinal Chemistry groups in general since it seamlessly integrates into organic synthesis workflows. Due to the affordable pricing, it is also a great solution for chemists in academia. Especially laboratories with high turnover of masters students and research interns will appreciate the robustness of the system.

Toluene-Assisted APCI and Elemental Composition Prediction Using a Compact Mass Spectrometer

OVERVIEW

  • Toluene-assisted APCI (TAPCI) can generate (M)+· and (M+H)+ ions from analytes that cannot be ionized by ESI or APCI.
  • Elemental formula prediction at 250 ppm accuracy and isotope distribution matching by TAMI (Tal Aviv Molecule Identifier) supports analyte identification.
  • Combining both TAPCI and TAMI on the expression compact mass spectrometer (CMS) provides a cost-effective analysis platform for a wide range of compounds.

INTRODUCTION

Many compounds in organic synthetic chemistry either have no functional group, a C=O carbonyl group, or protected functional groups and are difficult to ionize by ESI or APCI for detection by mass spectrometry. TAPCI has been shown to ionize compounds to (M)+· and (M+H)+ protonated molecules not accessible by ESI or APCI MS analysis. The ionization is believed to include a charge transfer reaction in the APCI plasma region of the source. Elemental formula prediction using TAMI allows analyte identification on a single quadrupole mass spectrometer with mass accuracy in the 250 ppm range, isotope pattern analysis and auto comparison to NIST databases. Here, we investigate the use of both techniques on the expression CMS as an attractive and cost-effective solution for analyte identification covering an increased compound space.

Rapid Screening for Fentanyl in Urine using the Advion Interchim Scientific expressionL CMS with the Touch Express™ Open Port Sampling Interface (OPSI)

Quick and easy analysis methods for drugs of abuse are in high demand from health practitioners and law enforcement agencies on a global scale. In 2017, it was found that fentanyl, a fast-acting synthetic painkiller that is nearly 100 times stronger than morphine, has become the most widely abused synthetic opioid medicine – to the point it has become a public health problem. In this application note, a simple method for fentanyl screening in urine is introduced, using Advion Interchim Scientific’s Touch Express™ Open Port Sampling Interface (OPSI) coupled with the expressionL Compact Mass Spectrometer (CMS).

OPSI was developed by Gary Van Berkel and Vilnos Kertesz of Oak Ridge National Laboratory. Paired with the electrospray ionization (ESI) source of the CMS, Touch Express™ OPSI offers a fast assay benchtop solution in a small-footprint, easy-to-use system.

Urinary Cortisol Quantitation Using Ultra High Pressure Liquid Chromatography/Compact Mass Spectrometry

Introduction

Cortisol is an important steroid hormone produced from cholesterol in the adrenal cortex. Its secretion is closely regulated by Adrenocorticotropic hormone (ACTH). Most cortisol is protein-bound, and only unbound cortisol is excreted in urine. Measurement of cortisol in urine is typically used in the diagnosis of Cushing’s syndrome, a disorder of hypercortisolism.

Although immunoassay methods have extremely high sensitivity, they are subject to variable interferences from other steroids and their conjugates. Liquid chromatography with tandem mass spectrometry is increasingly used in clinical analysis because of its higher specificity and selectivity than immunoassay methods. A simple and robust UHPLC/MS method will be introduced for urinary cortisol analysis and the dynamic range and sensitivity (LOD and LLOQ) of the UHPLC/CMS method will be evaluated.

Rapid Screening for Fentanyl in Urine Using a Compact Mass Spectrometer (CMS) with an Open Port Sampling Interface (OPSI)

Introduction

Fentanyl, a fast-acting synthetic painkiller about 100 times stronger than morphine, is also the most widely used synthetic opioid medicine in 2017.1 Its abuse is becoming a public health problem. A quick and easy analysis method for this drug is in high demand from health practitioners and law enforcement agencies.

The Touch Express™ Open Port Sampling Interface (OPSI),2,3 is designed for simple sampling of solids, liquids, sample preparation tips and fibers. Paired with the ESI of the expression® CMS, the product incorporates an open port of continuous low-volume solvent, flowing directly into the ESI for MS analysis. Any soluble sample touching the open port will be analyzed by the mass spectrometer in just seconds.

Here, a simple and quick analysis method for fentanyl in urine using Touch Express™ OPSI on the Advion expression® CMS is presented.

Cannabis-related Bioanalysis (from Plant to Forensic) using LC-CMS (Single Quad)

Introduction

The legalization of marijuana and hemp provides commercial opportunities as well as analytical challenges. Accurate and precise quantitative analysis of plant and medicinal products is needed in this new industry to document composition and assure the safety of cannabis products. LC/MS techniques can provide unparalleled selective and sensitive measurements for these purposes. Here we describe the use of a relatively inexpensive compact mass spectrometer for SIM LC/MS analysis of cannabis-related applications.

This poster was presented at ASMS 2018 Annual Conference in San Diego, CA.

Toluene-Assisted APCI Using a Compact Mass Spectrometer

Overview

  • Toluene-assisted APCI (TAPCI) can generate (M)+· and (M+H)+ molecules from analytes not MS accessible by ESI or APCI.
  • Elemental formula prediction at 250 ppm accuracy and isotope distribution matching by TAMI (Tal Aviv Molecule Identifier) supports analyte identification.
  • Combining both TAPCI and TAMI on a compact single quadrupole mass spectrometer (CMS) provides a cost-effective analysis platform for a wide compound space.