Review of Recent Advances in Lipid Analysis of Biological Samples via Ambient Ionization Mass Spectrometry

The rapid and direct structural characterization of lipids proves to be critical for studying the functional roles of lipids in many biological processes. Among numerous analytical techniques, ambient ionization mass spectrometry (AIMS) allows for a direct molecular characterization of lipids from various complex biological samples with no/minimal sample pretreatment. Over the recent years, researchers have expanded the applications of the AIMS techniques to lipid structural elucidation via a combination with a series of derivatization strategies (e.g., the Paternò–Büchi (PB) reaction, ozone-induced dissociation (OzID), and epoxidation reaction), including carbon–carbon double bond (C=C) locations and sn-positions isomers. Herein, this review summarizes the reaction mechanisms of various derivatization strategies for C=C bond analysis, typical instrumental setup, and applications of AIMS in the structural elucidation of lipids from various biological samples (e.g., tissues, cells, and biofluids). In addition, future directions of AIMS for lipid structural elucidation are discussed.

A Template for the Validation of DART-MS for Qualitative Seized Drugs Analysis

Direct analysis in real time mass spectrometry (DART-MS) is an increasingly employed tool for a wide range of forensic applications including seized drug analysis. A significant body of research surrounds DART-MS for the analysis of seized drugs and how it can be used to address many of the challenges caused by the increased presence of emerging drugs and novel psychoactive substances. A lack of available resources to help address validation, operation, training, and data interpretation needs is just one of the hurdles that laboratories face when adopting new technologies, such as DART-MS. To provide additional resources to assist in validation development, this work provides a template that can be adopted or adapted for DART-MS or other ambient ionization mass spectrometry techniques for qualitative seized drug analysis. The template, which was created as a result of recent implementation efforts, provides a description of validation studies with a focus on understanding the potential challenges and limitations caused by the prevalence of novel psychoactive substances and other emerging drugs. The studies address accuracy and precision, reproducibility, specificity, sensitivity, environmental factors, use in casework, and robustness. In addition to providing a template for validation, the results obtained from completing these studies on two high-resolution DART-MS systems are also presented. This work, and the corresponding supplemental information, was created to add to the available resources that laboratories can leverage to assist in overcoming the adoption hurdles of ambient ionization mass spectrometry methods such as DART-MS.

Rapid geographical indication of peppercorn seeds using corona discharge mass spectrometry

With increasing demands for more rapid and practical analyses, various techniques of ambient ionization mass spectrometry have gained significant interest due to the speed of analysis and abundance of information provided. Herein, an ambient ionization technique that utilizes corona discharge was applied, for the first time, to analyze and categorize whole seeds of black and white peppers from different origins. This setup requires no solvent application nor gas flow, thus resulting in a very simple and rapid analysis that can be applied directly to the sample without any prior workup or preparation. Combined with robust data pre-processing and subsequent chemometric analyses, this analytical method was capable of indicating the geographical origin of each pepper source with up to 98% accuracies in all sub-studies. The simplicity and speed of this approach open up the exciting opportunity for onsite analysis without the need for a highly trained operator. Furthermore, this methodology can be applied to a variety of spices and herbs, whose geographical indication or similar intellectual properties are economically important, hence it is capable of creating tremendous impact in the food and agricultural industries.

Characterizing the Dyes of Pre-Columbian Andean Textiles: Comparison of Ambient Ionization Mass Spectrometry and HPLC-DAD

The complex and colorful textiles of ancient Peru have long been a focus of technical study, particularly to characterize the sources of the wide variety of dyes utilized by these Andean artisans. This manuscript describes the characterization of the dyes of both primary (red, blue, and yellow) and secondary (purple, orange, and green) colors sampled from textiles spanning five major civilizations: the Paracas Necropolis, the Nazca, the Wari, the Chancay, and the Lambayeque, all from Peru. All but the Paracas Necropolis samples were part of technical conservation studies of the ancient South American textiles collections of the Michael C. Carlos Museum. Analysis of the dyes was carried out utilizing direct analysis in real time time-of-flight mass spectrometry (DART-MS) and paper spray MS. To validate these ambient ionization MS methods, the samples were further investigated using high-performance liquid chromatography (HPLC) with ultraviolet-visible diode array detection (DAD). These results show that ambient ionization MS methods are simple and fast for characterization of the general classes of dyes, e.g., plant reds vs. insect reds, and indigoids in blues and greens. Due to the myriad possible sources of yellow dyes and their tendency to undergo oxidative decomposition, positively identifying those components in these yarns was difficult, though some marker compounds and flavonoid decomposition products were readily identified by ambient ionization mass spectrometry.

Rapid Geographical Indication of Peppercorn Seeds Using Corona Discharge Mass Spectrometry

With increasing demands for more rapid and practical analyses, various techniques of ambient ionization mass spectrometry have gained interest due to its speed of analysis and the abundance of information provided. Herein, an ambient ionization technique that utilizes corona discharge was applied, for the first time, to analyze whole seeds of black and white peppers. This setup requires no solvent application or gas flow, thus resulting in a very simple and rapid analysis that can be applied directly to the sample without any prior workup or preparation. Combined with robust data pre-processing and subsequent chemometric analyses, this analytical method was capable of indicating the geographical origin of each pepper source with up to 98% accuracies in all sub-studies. The simplicity and speed of this approach open up the exciting opportunity for onsite analysis without the need for a highly trained operator. Furthermore, this methodology can be applied to a variety of spices and herbs, whose geographical indication or similar intellectual properties are economically important, hence it is capable of creating tremendous impact in food and agricultural industries.