Current Analytical Chemistry - Volume 18, Issue 9, 2022

Objective: Nowadays, most pharmaceutical formulations contain more than one drug because there are numerous advantages to multicomponent formulations, like patient compliance, enhanced efficacy, synergetic effects of both drugs, etc. This review paper describes the simultaneous estimation methods such as UV spectroscopy and high-performance liquid chromatography (HPLC) to determine various drug molecules and active pharmaceutical ingredients (APIs). In addition, the implementation of the quality by design (QbD) principle is used to illustrate how these approaches can be developed and validated. Methods: To estimate the drug content in these multicomponent formulations, several UV spectroscopy and HPLC methods have been developed and validated as per the available literature. UV spectrophotometry and HPLC are among the most critical tools in the analysis of drugs in pharmaceutical formulations. The QbD based optimization approach applies to developing the simultaneous estimation method, which could be designed with predefined objectives, that emphasize the product and process to maintain the desired quality. The QbD approach followed the guidelines mentioned in ICH Q8 (R2). Results: This review article gives brief information regarding the various QbD optimized UV and HPLC methods for simultaneous estimation of multicomponent formulations and their recent applications and elaborates on multiple steps in the development of the HPLC method along with their applications. Conclusion: The available information is very informative for multicomponent analysis, and it will open new paradigms in upcoming research in the field of analysis.

Background: In chemical and pharmaceutical analysis, hyphenated techniques range from the combinations involving separation-separation, separation-identification and identification-identification techniques and are widely used nowadays, as they hold many advantages like fast accurate analysis, a higher degree of automation, higher sample throughput, better reproducibility, specificity and sensitivity. They also reduce contamination due to closed systems and offer simultaneous separation and quantification, leading to better analysis. Objective: Though many reviews have appeared on hyphenated analytical techniques till date, in the past decade, their use has increased manifold and therefore, we thought it imperative to review the latest progress in this field. In the present article, an attempt has been made to cover the latest information on various hyphenated techniques like LC-MS (Liquid Chromatography-Mass Spectroscopy), GC-MS (Gas Chromatography-Mass Spectroscopy), LC-IR (Liquid Chromatography-Infra-Red Spectroscopy), as well as, LC-MS-MS (Liquid Chromatography-Mass Spectroscopy-Mass Spectroscopy), LC-NMR-MS (Liquid Chromatography-Nuclear Magnetic Resonance-Mass Spectroscopy), etc. Conclusion: This review describes a total of seventeen different hyphenated techniques, comprising mainly of the combinations of chromatographic techniques with spectroscopic techniques. We have tried to cover the latest information on various double hyphenated techniques like LC-MS , LC-NMR, LC-IR, HPTLC-MS, HPTLC-IR, GC-MS, GC-IR, GC-TLC, GC-AES, MS-MS, CE-MS, GC-NMR, as well as, triple hyphenated techniques like LC-MS-MS, LC-NMR-MS, LC-UV-MS, GC-MS-MS, GC-IR-MS. Mainly the principle, instrumentation, applications, and advantages of each of the techniques are discussed in this review. Also, disadvantages of a few techniques have been mentioned.

Food preservatives are used to keep bacteria, moulds, fungus, and yeast from spoiling food. Food additives are subject to strict rules (particularly in the European Union - EU), which consider the food to which they can be applied, maximum permissible quantities, chemical characterization, and purity. Sorbic acid, mainly potassium sorbate, is primarily utilised in a variety of commercially available foods. Various analytical strategies for an asynchronous and simultaneous estimation of potassium sorbate have been reported along with other preservatives in marketed formulations or food products. The Square-wave voltammetry using a cathodically prepared boron-doped diamond electrode, quick UHPLCfluorescent method, UV spectrophotometry, UHPLC-UV analysis, RP-HPLC, and mass spectrometry are some of the analytical techniques used. We have compiled various analytical methods to detect potassium sorbate with various other preservatives simultaneously or alone in marketed formulation. The authors feel that the studies summarised in this report will allow readers to choose the most acceptable and appropriate method for analysing this preservative.

Background: Nanoparticles based thin-film has remarkable challenges in water desalination. Carbon allotropes (carbon nanotubes, graphene sheets, and fullerene), metal and metal oxide nanoparticulates (titanium dioxide, silver, copper oxide, alumina, zinc oxide, and metal-organic framework, silica, halloysite, zeolite, aquaporin and cellulose) are the out breaking materials for water desalination. Advanced materials in membrane forms are impacting the desalination processes in terms of reverse osmosis, forward osmosis, pervaporation, membrane distillation, and electrodialysis. Objective: The main objective of this review is to provide a comprehensive overview of the various methods of water desalination and the role of nanoparticles in this regard. Methods: We discussed the overall studies describing the process of desalination, viz. distillation, osmosis, freeze-thaw desalination, electrodialysis, membranes, various types of nanoparticles used in desalination, current techniques in desalination, membrane technology with Algae treatment, environmental issues in desalination, future scopes and trials. Conclusion: Various polymeric membranes with graphene/carbon derivatives and nano-particulate integrated membranes are gaining enormous attention in the field of membrane technology for the desalination process. Nanoparticulate impregnated, and natural algae conjugated polymeric membranes may provide a plethora of possibilities for membrane filtration technology in the near future.

Objective: Inductively coupled plasma atomic emission spectroscopy (ICP/AES) has been used for the determination of phosphine residues in cereal and tissue biological samples. Methods: The method used is based on the reaction of phosphine residue with H2SO4 in a headspace vial, determining the phosphor of the liberated phosphine gas by ICP/AES at 213.6 nm. At this wavelength, there is a linear relationship between emission and concentration of phosphine in the range of 0.10 up to 0.50 μg g^-1 (R² = 0.990). The method is rapid and sensitive with the detection limit of 3.1 μg (S/N =3), and the precision expressed as relative standard deviations (RSD %) is below 12% for 10 replicates. Results: The obtained results showed good agreement with the GC/NPD method. Conclusion: In this study, we develop a rapid analysis, inexpensive, easier handling, simple, repeatable, and sensitive method for the determination of phosphine residue in various samples.

Aims: Understand the metabolic behavior of new psychoactive substances, furanyl fentanyl, TFMPP, and 5-MeO-DALT. Background: New psychoactive substances (NPS) are associated with several health and social harms on both the individual and societal levels. Many are not regulated and have become increasingly popular among drug users worldwide. The lack of clinical studies on the effects and toxicity of these drugs has made the interpretation of their toxicological symptoms difficult. Objective: Perform an in vitro metabolism study of new psychoactive substances furanyl fentanyl, TFMPP, and 5-MeO-DALT, revealing their possible metabolites and metabolic pathways in the human liver microsome. Methods: A regular human liver microsomal system was used to investigate the potential biotransformation of furanyl fentanyl, TFMPP, and 5-MeO-DALT in vitro, and high-resolution mass spectrometry (LC-Q/TOF-MS) was used to perform metabolite detection and identification. Results: The three components were substantially metabolized in 4 hours with varied metabolic pathways, and most of the metabolites were generated through phase I metabolic reactions. Furanyl fentanyl underwent the metabolic pathways of epoxidation and hydration, furanyl ring-opening and oxidation, hydroxylation, hydrolysis of the amide group, and N-dealkylation; TFMPP underwent the metabolic pathways of hydroxylation, and the successive piperazidine ring scission; while 5-MeO-DALT underwent the metabolic pathways of O-demethylation and glucuronidation, dihydroxylation, hydroxylation, oxidation, O-demethylation, N-dealkylation and methylation and N-dealkylation. Conclusion: Our data would contribute to a better understanding of furanyl fentanyl, TFMPP, and 5- MeO-DALT in their in vitro metabolism study, which was beneficial to predicting their metabolic behavior in vivo, and promoting their drug monitoring in both clinically used and socially/illegally abused.

Background: The use of modified electrochemical sensors is essential for the detection of antibiotic drug abuse. The main objective of this article is to develop a silk-derived carbon material for the modification of pyrolytic graphite electrodes (PGE) for the sensitive detection of chloramphenicol (CAP). Methods: We proposed a pyrolysis synthesis of porous carbon nanosheets (Fe-Silk PNC) using silk as a precursor. Properties of carbon nanosheets had been improved by the Fe-Nx atoms doping, which was attributed to the β-sheet structures and amino-group-rich chemical structures of silk fibroin, and this material has been used to modify the pyrolytic graphite electrode (PGE) for the electrochemical determination of CAP. Scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR) were used to determine the morphology and properties of Fe-Silk PNC surface. In the electrochemical determination, cyclic voltammetry (CV) showed a superior current response while bare electrode performed an inferior result. In addition, different scan rate, pH, accumulation time and accumulation potential were carefully optimized, which proved that this material is appropriate for CAP detection. Finally, differential pulse voltammetry (DPV) method was used for quantitative measurements. Results: In this study, DPV determination of CAP showed the linear relationship with increasing concentration ranged from 1 to 200 μM, and the low detection limit was 0.57 μM (S/N = 3). SEM and FT-IR results further demonstrated the N-doped carbon nanomaterials were successfully synthesized. With excellent sensing performance achieved, the practicability of the sensor has been evaluated to detect CAP in chicken, shrimps and fish. Conclusion: In summary, a silk derived biomass porous carbon nanomaterial Fe-Silk PNC was simply fabricated and used as a novel electrode material. This kind of novel Fe-Silk PNC modified electrode exhibited excellent sensitivity, anti-interference ability, repeatability, wide linear rang, and was successfully used for determination of CAP in real samples. Therefore, the biomass derived nanomaterial is expected to be used in new sensing materials.

Aim: The aim of this work is to fabricate pipette tip electrodes for the capillary electrophoretic determination of nicotine and phenolic compounds in tobacco. Background: The content of nicotine affects not only the quality of tobacco products but also the health of smokers. Phenolic compounds are important flavor precursors in tobacco. The quantity of phenolic compounds is one of the most important evaluation indicators of tobacco quality. It is of high importance to determine nicotine and phenolic compounds in tobacco for quality control and the health of smokers. Objective: A method based on capillary electrophoresis and amperometric detection was developed for the simultaneous determination of nicotine, rutin, chlorogenic acid, quercetin, ferulic acid, gallic acid, and protocatechuic acid in tobacco leaves. Pipette electrodes were designed and fabricated for their amperometric detection. Methods: Nicotine, rutin, chlorogenic acid, quercetin, ferulic acid, gallic acid, and protocatechuic acid were determined by capillary electrophoresis in combination with the detection electrodes that were fabricated by packing the composite of carbon nanotube and epoxy in pipette tips. Results: Detection potentials, the acidity and concentrations of background electrolyte, separation voltages, and injection times were optimized. At a high voltage of 12 kV, separation of the seven analytes could be achieved in less than 11 min in a piece of 40 cm long fused silica capillary with a background electrolyte of 50 mM borate buffer (9.2). Linearity was observed between the peak currents and the concentrations, with the limits of detection ranging from 0.1 to 0.2 μM for the seven analytes at the pipette electrodes. The method was applied in the simultaneous determination of nicotine and phenolic compounds with satisfactory assay results. Conclusion: The pipette tip electrodes were successfully coupled with capillary electrophoresis for tobacco analysis. The CE-AD method provides not only a simple approach for the quality control of tobacco and its preparations but also an alternative technique for the constituent and fingerprint investigation of other plants.