A review of pulsed electrochemical detection following liquid chromatography and capillary electrophoresis

A high-performance anion-exchange chromatographic method for the fast analysis and precise determination of varied glucose-derived acids during biomass biorefinery

Glucose-derived acids for the further production of value-added medicine, food additives, and polymers, will promote lignocellulosic biomass biorefinery industry. In response to the diversity and complexity, a new method was established by employing high performance anion exchange chromatography (HPAEC) coupled with a CarboPac™ PA200 column, for the precise and fast determination of glucose, gluconic acid, glucuronic acid, 2-ketogluconic acid, 5-ketogluconic acid and glucaric acid. Based on the analysis of tiny varieties in retention behavior, a gradient elution mode was designed and optimized for the quantitative and qualitative analysis. The protocol displayed acceptable linearity (R2 ≥ 0.995), commendable average recovery rate (95.28% ∼ 99.89%), satisfactory precision (RSD% ≤ 1.5%), and sufficient resolution (R > 6). Additionally, this method was successfully applied to the high-value biorefining process, which confirmed the practicability and accuracy. The results demonstrated that HPAEC has good detection performance for glucose and its derivative acids, and provide key identification technical support for the high-value utilization of lignocellulose.

Ion Chromatography and Related Techniques in Carbohydrate Analysis: A Review

Ion chromatography and related techniques have been the most popular separation methods used in the determination of organic and inorganic anions and cations, predominantly in water and wastewater samples. Making progress in their development and introducing new stationary phases, methods of detection and preparation of samples for analyses have given rise to the broadening of their analytical range. Nowadays, they are also used for substances that are not ionic by nature but can convert to such forms under certain conditions. These encompass, among others, carbohydrates, whose role and significance in humans' lives and environment is invaluable. Their presence in the air is mostly due to the industrial burning of biomass for energy production purposes. In addition, the content of sugars in plants, fruits and vegetables, constituting the base of human diets, affects our health condition. Given that, there is not only a need for their determination by means of routine methods but also for searching for novel analytical solutions. Based on literature data from the past decade, this paper presents the possibilities and examples of applications regarding ion chromatography and related techniques for the determination of carbohydrates in environmental samples, biomass and plants constituting food or raw materials for food production. Attention has been paid to the virtues and limitations of the discussed separation methods in this respect. Moreover, perspectives on their development have been defined.

Maximizing Electrochemical Information: A Perspective on Background-Inclusive Fast Voltammetry

This perspective encompasses a focused review of the literature leading to a tipping point in electroanalytical chemistry. We tie together the threads of a "revolution" quietly in the making for years through the work of many authors. Long-held misconceptions about the use of background subtraction in fast voltammetry are addressed. We lay out future advantages that accompany background-inclusive voltammetry, particularly when paired with modern machine-learning algorithms for data analysis.

Multiple pulse amperometry in low pressure chromatography for parallel determination of oxidizable and reducible compounds. Analysis of a green coffee extract as a case study

In this paper, the determination of both oxidizable and reducible compounds within a single chromatographic run is exploited for the first time, using a low-pressure chromatographic system and multiple pulse amperometric detection. The case study selected focussed on the analysis of green coffee extracts. The separation of the compounds was carried out using a 1-cm length monolithic column and an eluent prepared by mixing an aqueous solution of an ion-pair reagent, perfluoroheptanoic acid (PFHpA), and acetonitrile. The parallel determination of oxidizable and reducible compounds was performed by application of two consecutive pulses, E1 = +1.6 V and E2 = -1.5 V. At anodic conditions, the chromatographic peaks for 5-caffeoylquinic acid (5-CQA), caffeine and 5-feruloylquinic acid (5-FQA) were detected, while at cathodic conditions, a chromatographic peak was ascribed for trigonelline. In the developed methodology, the use of multiple pulse amperometry provided better sensitivity if compared to previously described amperometric methodologies determining either oxidizable or reducible compounds. Detection limits for the referred compounds of ca. 1 × 10-5 mol L-1, an analysis rate of 12 h-1 and an acetonitrile consumption of 0.07 mL per analysis were achieved. The approach presented demonstrates the possibility of combining low pressure chromatographic systems and multiple pulse amperometry, in the development of new, low-cost and fast methodologies for multi-analyte determinations.

Comparison of Mobile Phone and CCD Cameras for Electrochemiluminescent Detection of Biogenic Amines

Biogenic amines are an important and widely studied class of molecules due to their link to the physiological processes of food-related illnesses and histamine poisoning. Electrochemiluminescent (ECL) detection offers an inexpensive and portable analytical method of detection for biogenic amines when coupled with recent advancements in low-cost carbon-based electrodes and a smartphone camera. In this work, a mobile phone camera was evaluated against a piece of conventional instrumentation, the charge-coupled device, for the detection of ECL from the reaction of biogenic amines with the luminescent compound tris(2,2'-bipyridyl)ruthenium(II). Assisted by a 3D-printed light-tight housing, the mobile phone achieved limits of detection of 127, 425 and 421 μM for spermidine, putrescine, and histamine, respectively. The mobile phone's analytical figures of merit were lesser than the CCD camera but were still within the range to detect contamination. In an exploration of real-world samples, the mobile phone was able to determine the contents of amines in skim milk on par with that of a CCD camera.

Electrochemical Amino Acid Sensing: A Review on Challenges and Achievements

The rapid growth of research in electrochemistry in the last decade has resulted in a significant advancement in exploiting electrochemical strategies for assessing biological substances. Among these, amino acids are of utmost interest due to their key role in human health. Indeed, an unbalanced amino acid level is the origin of several metabolic and genetic diseases, which has led to a great need for effective and reliable evaluation methods. This review is an effort to summarize and present both challenges and achievements in electrochemical amino acid sensing from the last decade (from 2010 onwards) to show where limitations and advantages stem from. In this review, we place special emphasis on five well-known electroactive amino acids, namely cysteine, tyrosine, tryptophan, methionine and histidine. The recent research and achievements in this area and significant performance metrics of the proposed electrochemical sensors, including the limit of detection, sensitivity, stability, linear dynamic range(s) and applicability in real sample analysis, are summarized and presented in separate sections. More than 400 recent scientific studies were included in this review to portray a rich set of ideas and exemplify the capabilities of the electrochemical strategies to detect these essential biomolecules at trace and even ultra-trace levels. Finally, we discuss, in the last section, the remaining issues and the opportunities to push the boundaries of our knowledge in amino acid electrochemistry even further.

A Status Update on Pharmaceutical Analytical Methods of Aminoglycoside Antibiotic: Amikacin

Amikacin (AMK) is one of the commonly used aminoglycoside antibiotics, introduced for clinical use in patients suffering from bacterial infections especially life-threatening gram-negative infections. Due to lack of chromophore in the molecule, the detection of AMK during analysis is a challenge. Thus, pre and post-column derivatization techniques are generally used for AMK estimation. This review focuses on different analytical methods used for detection and quantification of AMK in pure or fixed dose combination pharmaceutical formulations and biological samples. Various reported methods described in the literature include high-performance liquid chromatography techniques, pulsed electrochemical detection techniques, Chemiluminescence techniques, Capillary electrophoresis and immunological methods. High-performance-liquid-chromatography based methods with UV/Vis spectrophotometric, fluorescence and mass spectrometric detection are the most prevailing methods employed for the analysis of AMK. This review could be of significant importance in the area of future AMK analytical method development studies.

Current landscape of protein glycosylation analysis and recent progress toward a novel paradigm of glycoscience research

This review covers the basics and some applications of methodologies for the analysis of glycoprotein glycans. Analytical techniques used for glycoprotein glycans, including liquid chromatography (LC), capillary electrophoresis (CE), mass spectrometry (MS), and high-throughput analytical methods based on microfluidics, were described to supply the essentials about biopharmaceutical and biomarker glycoproteins. We will also describe the MS analysis of glycoproteins and glycopeptides as well as the chemical and enzymatic releasing methods of glycans from glycoproteins and the chemical reactions used for the derivatization of glycans. We hope the techniques have accommodated most of the requests from glycoproteomics researchers.