Leveraging 3D printing to enhance mass spectrometry:A review

The use of 3D printing in the chemical and analytical sciences has gained a lot of momentum in recent years. Some of the earliest publications detailed 3D-printed interfaces for mass spectrometry, which is an evolving family of powerful detection techniques. Since then, the application of 3D printing for enhancing mass spectrometry has significantly diversified, with important reasons for its application including flexible integration of different parts or devices, fast customization of setups, additional functionality, portability, cost-effectiveness, and user-friendliness. Moreover, computer-aided design (CAD) and 3D printing enables the rapid and wide distribution of scientific and engineering knowledge. 3D printers allow fast prototyping with constantly increasing resolution in a broad range of materials using different fabrication principles. Moreover, 3D printing has proven its value in the development of novel technologies for multiple analytical applications such as online and offline sample preparation, ionization, ion transport, and developing interfaces for the mass spectrometer. Additionally, 3D-printed devices are often used for the protection of more fragile elements of a sample preparation system in a customized fashion, and allow the embedding of external components into an integrated system for mass spectrometric analysis. This review comprehensively addresses these developments, since their introduction in 2013. Moreover, the challenges and choices with respect to the selection of the most appropriate printing process in combination with an appropriate material for a mass spectrometric application are addressed; special attention is paid to chemical compatibility, ease of production, and cost. In this review, we critically discuss these developments and assess their impact on mass spectrometry

3D-Printed Paper Spray Ionization Cartridge with Integrated Desolvation Feature and Ion Optics

In this work we present the application of 3D-printing for the miniaturization and functionalization of an ion source for (portable) mass spectrometry (MS). Two versions of a 3D-printed cartridge for paper spray ionization (PSI) are demonstrated, assessed, and compared. We first focus on the use of 3D-printing to enable the integration of an embedded electrostatic lens and a manifold for internal sheath gas distribution and delivery. Cartridges with and without a sheath gas manifold and an electrostatic lens are compared with respect to analytical performance and operational flexibility. The sensitivity and limit of detection are improved in the cartridge with an electrostatic lens and sheath gas manifold compared to the cartridge without (15% and over 6.5× smaller, respectively). The use of these focusing elements also improved the average spray stability. Furthermore, the range of potentials required for PSI was lower, and the distance to the MS orifice over which spray could be obtained was larger. Importantly, both setups allowed quantification of a model drug in the ng/mL range with single-stage MS, after correction for spray instability. Finally, we believe that this work is an example of the impact that 3D-printing will have on the future of analytical device fabrication, miniaturization, and functionalization

Reinventing (Bio)chemical Analysis with Paper

This paper focuses on one of the most commonly encountered materials in our society, namely paper. Paper is an inherently complex material, yet its use provides for chemical analysis approaches that are elegant in their simplicity of execution. In the first half of the previous century, paper in scientific research was used mainly for filtration and chromatographic separation. While its use decreased with the rise of modern elution chromatography, paper remains a versatile substrate for low-cost analytical tests. Recently, we have seen renewed interest to work with paper in (bio)analytical science, a result of the growing demand for inexpensive, portable analysis. Dried blood spotting, paper microfluidics, and paper spray ionization are areas in which paper is (re)establishing itself as an important material. These research areas all exploit several properties of paper, including stable sample storage, passive fluid movement and manipulation, chromatographic separation/extraction, modifiable surface and/or volume, easily altered shape, easy transport, and low cost. We propose that the real, and to date underexploited, potential of paper lies in utilizing its combined characteristics to add new dimensions to paper-based (bio)chemical analysis, expanding its applicability. This article provides the reader with a short historical perspective on the scientific use of paper and the developments that led to the establishment of the aforementioned research areas. We review important characteristics of paper and place them in a scientific context in this descriptive, yet critical, assessment of the achieved and the achievable in paper-based analysis. The ultimate goal is the exploration of integrative approaches at the interface between the different fields in which paper is or can be used.</p

Best practices and current implementation of emerging smartphone-based (bio)sensors - Part 2: Development, validation, and social impact

The amalgamation of computer-like capabilities and portability of modern smartphones has fuelled their implementation as detectors and interfaces in emerging smartphone-based (bio)sensors (SbSs) for e.g. healthcare, point-of-need, food safety, environmental science, and forensics systems. SbSs intrinsically carry great potential for consumer diagnostics, and future ‘citizen science’ approaches, which have far-reaching implications for the technological, legal, and ethical aspects associated with the research, development, and deployment of SbSs. In this review (part 2 of a pair of review papers), we evaluated the pertinent literature on issues concerning the development and validation of SbSs, and we address their potential social impact. Finally, insights gleaned are combined in a set of recommendations to guide future ethical, sustainable, and efficient research, development, and deployment of SbSs.</p

Critical assessment of recent trends related to screening and confirmatory analytical methods for selected food contaminants and allergens

Food contaminants monitoring is conducted in an intensive manner yet, there are still food safety scandals related to various chemical compounds. This fact highlights the need to review the requirements posed by the current legal framework on analytical methods performance and evaluate its application in published studies. Herein, we present an inventory including more than 470 publications on screening and confirmatory methods, which were used to control hazardous compounds such as pesticides, antibiotics, mycotoxins, aquatic toxins and allergens. Analytical performance characteristics, trends and state of the art, both merits and shortcomings, are critically discussed and summarized in excel tabulations. This repository highlights the ever-increasing use of screening methods and the necessity to confirm their performance by applying confirmatory methods. In conclusion, more effort is needed on validation and benchmarking, especially of newly developed technology such as smartphone-based methods, to avoid false-negative results and ensure that methods fit for purpose.</p