Analytica Chimica Acta (v.835, #C)

Display OmittedBioimaging using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) offers the capability to quantify trace elements and isotopes within tissue sections with a spatial resolution ranging about 10–100 μm. Distribution analysis adds to clarifying basic questions of biomedical research and enables bioaccumulation and bioavailability studies for ecological and toxicological risk assessment in humans, animals and plants. Major application fields of mass spectrometry imaging (MSI) and metallomics have been in brain and cancer research, animal model validation, drug development and plant science. Here we give an overview of latest achievements in methods and applications. Recent improvements in ablation systems, operation and cell design enabled progressively better spatial resolutions down to 1 μm. Meanwhile, a body of research has accumulated covering basic principles of the element architecture in animals and plants that could consistently be reproduced by several laboratories such as the distribution of Fe, Cu, Zn in rodent brain. Several studies investigated the distribution and delivery of metallo-drugs in animals. Hyper-accumulating plants and pollution indicator organisms have been the key topics in environmental science. Increasingly, larger series of samples are analyzed, may it be in the frame of comparisons between intervention and control groups, of time kinetics or of three-dimensional atlas approaches.
Keywords: Elemental bio-imaging; Laser ablation inductively coupled plasma mass spectrometry; LA-ICP-MS; Trace metal imaging;

Display OmittedFollowing the green analytical chemistry principles, an efficient strategy involving second-order data provided by liquid chromatography (LC) with diode array detection (DAD) was applied for the simultaneous determination of estriol, 17β-estradiol, 17α-ethinylestradiol and estrone in natural water samples. After a simple pre-concentration step, LC–DAD matrix data were rapidly obtained (in less than 5 min) with a chromatographic system operating isocratically. Applying a second-order calibration algorithm based on multivariate curve resolution with alternating least-squares (MCR-ALS), successful resolution was achieved in the presence of sample constituents that strongly coelute with the analytes. The flexibility of this multivariate model allowed the quantification of the four estrogens in tap, mineral, underground and river water samples. Limits of detection in the range between 3 and 13 ng L−1, and relative prediction errors from 2 to 11% were achieved.
Keywords: Liquid chromatography; Diode array detection; Multivariate curve resolution; Estrogens; Natural waters;

An electrochemical sensor based on PAR/EGR/GCE via a cooperation of the potentiostatic technique and cyclic voltammetry was first fabricated for the determination of CPFX with satisfied detecting result of real samples.Display OmittedA glassy carbon electrode modified with poly(alizarin red)/electrodeposited graphene (PAR/EGR) composite film was prepared and applied to detect ciprofloxacin (CPFX) in the presence of ascorbic, uric acid and dopamine. The morphology and interface property of PAR/EGR films were examined by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The electrocatalytic oxidation of CPFX on AR/EGR was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The linearity ranged from 4 × 10−8 to 1.2 × 10−4  M with a detection limit (S/N = 3) of 0.01 μM. The modified electrode could be applied to the individual determination of CPFX as well as the simultaneous determination of CPFX, ascorbic acid, uric acid and dopamine. This method proved to be a simple, selective and rapid way to determine CPFX in pharmaceutical preparation and biological media.
Keywords: Alizarin red; Potentiostatically electrodeposited graphene; Ciprofloxacin; Simultaneously detection;

Display OmittedIn this work, the capabilities of solid phase microextraction were exploited in a fully optimized SPME-GC-QqQ-MS analytical approach for hydrazine assay. A rapid and easy method was obtained by a simple derivatization reaction with propyl chloroformate and pyridine carried out directly in water samples, followed by automated SPME analysis in the same vial without further sample handling. The affinity of the different derivatized compounds obtained towards five commercially available SPME coatings was evaluated, in order to achieve the best extraction efficiency. GC analyses were carried out using a GC-QqQ-MS instrument in selected reaction monitoring (SRM) acquisition mode which has allowed the achievement of high specificity by selecting appropriate precursor–product ion couples improving the capability in analyte identification. The multivariate approach of experimental design was crucial in order to optimize derivatization reaction, SPME process and tandem mass spectrometry parameters. Accuracy of the proposed protocol, tested at 60, 200 and 800 ng L−1, provided satisfactory values (114.2%, 83.6% and 98.6%, respectively), whereas precision (RSD%) at the same concentration levels were of 10.9%, 7.9% and 7.7% respectively. Limit of detection and quantification of 4.4 and 8.3 ng L−1 were obtained. The reliable application of the proposed protocol to real drinking water samples confirmed its capability to be used as analytical tool for routine analyses.
Keywords: Hydrazine; Drinking water; Solid phase microextraction; Gas chromatography; Chloroformates; Experimental design;

Display OmittedThe breakthrough (BT) properties of Tenax TA sorbent were challenged by gaseous standards containing a suite of 13 volatile organic compounds (VOC): (1) aromatic hydrocarbons: benzene (B), toluene (T), p-xylene (p-X), and styrene (S), (2) aldehydes: acetaldehyde (AA), propionaldehyde (PA), butyraldehyde (BA), isovaleraldehyde (IA), and valeraldehyde (VA), (3) ketones: methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK), and (4) two others: isobutyl alcohol (i-BuAl) and butyl acetate (BuAc). To this end, 1–3 L of standards (10–50 ppb) were loaded on the two sorbent tubes (ST) connected in series at 100 mL min−1. The front ST-1 was used for calibration purposes, while the ST-2 for breakthrough (recovery criterion of <1% with p-xylene as the key datum point). Although aromatic hydrocarbons generally met such criterion, benzene was readily distinguishable with the maximum BT. The BT for the aldehydes exhibited ∼100% (AA) ≥ 85% (PA) ≥ 45% (BA) ≥ 30% (VA and IVA). There is good correlation between ST-2 recovery vs. carbon number for >C=O entity (aldehydes, ester, and ketones). As such, BT is essentially concentration independent and relatively predictable across different functional groups and between the homologues. However, the BT behavior of ppb level VOCs is no longer consistent for certain species (like benzene or MEK) relative their ppm counterparts. This variation is explained by the Langmuir equation in which the 1/BTV is proportional to analyte gas-phase concentration, if the gas-phase/sorbent partition coefficient is large.
Keywords: Volatile organic compounds; Aromatic; Sorbent tube; Breakthrough; Thermal desorption;

A new nano optical sensor for diagnosis of different diseases of seminal vesicle and sexual gland was prepared. The working principle of the method depends on the determination of the fructose concentration in semen of different patients by using nano optical sensor thin film Sm-doxycycline doped in sol–gel matrix.Display OmittedA new method in which a nano optical sensor for diagnosis of different diseases of seminal vesicle and sexual gland was prepared. The working principle of the method depends on the determination of the fructose concentration in semen of different patients by using nano optical sensor thin film Sm-doxycycline doped in sol–gel matrix. The assay is based on the quenching of the characteristic emission bands of Sm3+ present in silica doped Sm-doxycycline nanooptode thin film by different fructose concentrations in acetonitrile at λ ex  = 400 nm. This method was optimized for parameters, such as, solvent effect, operational stability, shelf life and interference parameters. Good and reproducible linearity (1 × 10−9  – 5.0 × 10−5  mol L−1) with a detection limit of 9.0 × 10−10  mol L−1 and quantification limit of detection (LOQ) 2.7 × 10−9  mol L−1 were obtained. Seminal fructose determination in different patient samples after appropriate dilutions confirmed the reliability of this technique. The method was successfully applied for routine fructose monitoring in human semen samples of different cases such as; obstructive and non-obstructive azoospermia, inflammation of male accessory glands, atrophy of seminal vesicle, congenital vas deferens and retrograde ejaculation.
Keywords: Seminal fructose; Sm-doxycycline; Nano optical sensor thin flim; Luminescence intensity; Quenching; Seminal vesicle;