The multi-channel potentiostat: Development and evaluation of a scalable mini-potentiostat array for investigating electrochemical reaction mechanisms

A potentiostat is an essential piece of analytical equipment for studying electrochemical devices and reactions. As the design of electrochemical devices evolve, applications for systems with multiple working electrodes have become more common. These applications drive a need for low-cost multi-channel potentiostat systems. We have developed a portable, low-cost and scalable system with a modular design that can support 8 to 64 channels at a cost as low as $8 per channel. This design can replace the functionality of commercial potentiostats which cost upwards of $10k for certain applications. Each channel in the multi-channel potentiostat has an independent adjustable voltage source with a built-in ammeter and switch, making the device flexible for various configurations. The multi-channel potentiostat is designed for low current applications (nA range), but its purpose can change by varying its shunt resistor value. The system can either function as a standalone device or remotely controlled. We demonstrate the functionality of this system for the control of a 24-channel bioelectronic ion pump for open- and closed- loop control of pH.

Basslines, brains, bits, bytes, and burgers: Working with, and within the limits to, Marxism

This paper considers some of what it means to work with, and within the limits to, Marxism. I make reference to two sets of inquiries where Marxism matters but remains at the margins of things. My focus will be on human cognition and digital life. To balance things, I then highlight some issues where Marxism is much more to the fore, specifically what I loosely refer to as "foodscapes." Finally, I conclude the essay with some further personal comments on my engagement with Marxism. Throughout, I want to give some expression to the sensation of walking a fine line between remaining committed to the conclusion that capitalist social relations are an enormous problem for human society but finding also that Marxism does not provide enough of the analytical equipment to answer how we should move beyond it. At the same time, I try to offer reflections on critical intellectual thought and action as a tentative and iterative experience, rather than an engagement framed by the security that one can find enough of what’s needed in Marxism.

Analiza mikrośladów trinadtlenku triacetonu (TATP) w fazie gazowej z zastosowaniem TD-GC/MS

W artykule opisano metodykę wykrywania trinadtleneku triacetonu (TATP) w postaci par oraz śladów powierzchniowych z wykorzystaniem chromatografi gazowej sprzężonej ze spektrometrią mas wyposażoną w system do termodesorpcji (TD-GC/MS). Rozwiązania techniczne aparatury analitycznej umożliwiają wybór jednej z dwóch metod wprowadzenia par analitu w celu identyfikacji – pośrednio ze złoża TENAX TA lub bezpośrednio z obiektów badań. Dodatkowo zastosowanie elementu GERSTEL CIS odgrywającego rolę koncentratora substancji powoduje, że jest możliwa identyfikacja już nawet nanośladowych ilości TATP. W artykule przedstawiono schemat działania termodesorpcji w TD-GC/MS z jednoczesnym zwróceniem uwagi na cechy fizyczne substancji warunkujące osiągnięcie zadowalających wyników. Micro-traces analysis of triacetone triperoxide (TATP) in the form of vapours using TD-GC/MS The article discusses the method of detecting triacetone triperoxide (TATP) in the form of vapours and surface traces using gas chromatography with a thermal desorption system of mass spectrometry (TD-GC/MS). The technical solutions of analytical equipment make it possible to choose one or two methods for introducing analyte vapour for identification – indirectly from the TENAX TA deposit or directly from the research objects. In addition, the use of the GERSTEL CIS element as a substance concentrator renders identification of even nano-trace amounts of TATP possible. The article presents the experimental procedure of the thermal desorption TD-GC/MS and simultaneously draws attention to physical properties of the substance determining the achievement of satisfactory results.

From Close-Ups to Long Shot

In a context in which EU case law is increasingly politicized, this chapter questions our analytical equipment when it comes to understanding the ‘political role’ of the Court of Justice of the European Union (CJEU). Moving from close-ups to long shot views of EU case-lawyering, the chapter repositions judicial decision-making in a dense web of political, social, and professional ramifications within and outside the Court itself. By articulating micro, meso, and macro levels of analysis, it escapes ontological discussions about the political nature of the Court (‘neoliberal’, ‘federalist’, etc.) and suggests a research strategy able to empirically measure and geographically map out the Court’s embeddedness in Europe’s laws, politics, and societies.

Recent Materials Developed for Dispersive Solid Phase Extraction

Solid phase extraction (SPE) is an analytical procedure developed with the purpose of separating a target analyte from a complex sample matrix prior to quantitative or qualitative determination. The purpose of such treatment is twofold: elimination of matrix constituents that could interfere with the detection process or even damage analytical equipment as well as enriching the analyte in the sample so that it is readily available for detection. Dispersive solid phase extraction (dSPE) is a recent development of the standard SPE technique that is attracting growing attention due to its remarkable simplicity, short extraction time and low requirement for solvent expenditure, accompanied by high effectiveness and wide applicability. This review aims to thoroughly survey recently conducted analytical studies focusing on methods utilizing novel, interesting nanomaterials as dSPE sorbents, as well as known materials that have been only recently successfully applied in dSPE techniques, and evaluate their performance and suitability based on comparison with previously reported analytical procedures.