Analytica, Volume 1, Issue 1 (December 2020) – 6 articles

Nowadays, the challenges in analytical chemistry, and mostly in quantitative analysis, include the development and validation of new materials, strategies and procedures to meet the growing need for rapid, sensitive, selective and green methods. In this context, considering the constantly updated International Guidelines, constant innovation is mandatory both in the pre-treatment procedures and in the instrumental configurations to obtain reliable, true, and reproducible information. In this context, additionally to the classic plasma (or serum) matrices, biopsies, whole blood, and urine have seen an increase in the works that also consider non-conventional matrices. Obviously, all these studies have shown that there is a correlation between the blood levels and those found in the new matrix, in order to be able to correlate and compare the results in a robust way and reduce any bias problems. This review provides an update of the most recent developments currently in use in the sample pre-treatment and instrument configurations in the biological/clinical fields. Furthermore, the review concludes with a series of considerations regarding the role and future developments of Analytical Chemistry in light of the forthcoming challenges and new goals to be achieved. Full article

In palliative care, continuous subcutaneous infusion (CSCI) is common practice for drug administration when oral application of drugs is not feasible or not reliable anymore. However, use of CSCI is limited to chemical stability of drugs and their combination in carrier solution. To determine the stability of different mixtures of commonly used drugs in palliative care, a multi-analyte UHPLC-DAD method controlled by an internal standard was successfully developed. The method was validated in terms of specificity, accuracy, precision, and linearity across the calibration range. Seven analytes could be separated within 10 min by C18-reversed phase chromatography. The method was successfully applied to close gaps in stability data and complete missing data for decision makers in health care units. Our results indicated the stability of binary mixtures and one ternary mixture in 0.9% saline and 5% glucose as carrier solutions. The obtained data will support pharmacists in palliative care for the preparation of parenteral drug solutions in the future. Full article

A method for the analysis of weak anionic surfactants based on N-acyl amino acids was developed. The surfactants were derivatized using 2,4′-dibromoacetophenone yielding 4′-bromophenacyl esters suitable for spectrophotometric detection. Surfactants containing glycine, threonine and glutamic acid were analyzed after derivatization using reversed-phase liquid chromatography with UV/Vis and MS detection. The gradient profile was optimized using isocratic retention data of N-acyl-linked fatty acid homologues. The relative content of the homologues of N-acyl-linked fatty acids was expressed using the determined method. The intraday repeatability and stability of the prepared derivatives was tested. The relative content of fatty acids in the surfactants was correlated with the most common sources of fatty acids, showing high Pearson’s correlation coefficients with the typical fatty acids profile of a coconut oil. Full article

The analysis of urinary organic acids is useful for patients suspected to have inborn errors of metabolism known as organic acidurias. These diseases cause an accumulation of organic acids in body fluids and their abnormal excretion in urines. By means of chemometrics tools, such as principal component analysis and multiple linear regression, it was concluded that the conditions used in our laboratory are really the most suitable to achieve high yields of analytes. Full article

Back in 1894, Wilhelm Ostwald defined analytical chemistry as “the art of recognizing different substances and determining their constituents”, which “occupies a prominent position among the applications of science, since the questions it allows us to answer arise wherever chemical processes are used for scientific or technical purposes” [...] Full article

Analytical methods based on the Berthelot reaction were recently adapted for determining monochloramine (MCA: NH₂Cl) in freshwater. The specificity of the Berthelot reaction with regard to MCA is related to the need for two exchangeable hydrogen atoms to form indophenol blue. MCA can thus be distinguished from organic N-chloramines, which have only one exchangeable hydrogen atom. Monobromamine (MBA: NH₂Br) may be formed during chlorination of seawater containing ammonium ions. Quantifying MBA is quite challenging and no method has been reported for its specific determination in seawater. As MBA also has two exchangeable hydrogen atoms, its reactivity might be analogous to that of MCA, but this hypothesis has never been investigated. The aim of this study was to examine the applicability of the so-called “indophenol method” for the determination of the MBA in freshwater and seawater samples. The reaction between MBA and Berthelot reagents was studied in both ultrapure water and artificial seawater. The reaction products were characterized by using gas chromatography coupled to mass spectrometry (GC–MS), Fourier transform-ion cyclotron resonance mass spectrometry (FT–ICR MS), and UV–vis spectroscopy. Results showed that colorimetric methods based on the Berthelot reaction were not suitable for measuring MBA in freshwater or seawater, since NH₂Br reacts with alkaline phenol derivative via electrophilic substitution to form ortho- and para-brominated phenols instead of forming indophenol. Full article