Extraction Procedure Research Articles

Pharmacological Significance of Boraginaceae with Special Insights into Shikonin and Its Potential in the Food Industry.

Shikonin is a naphthoquinone pigment present in the hairy roots of the plant species from the Boraginaceae family. The compound has been well investigated for its highly efficient medicinal, antioxidant, and antimicrobial properties. Various extraction methodologies have been employed to maximise yield while minimising waste production of shikonin and its derivatives. Despite substantial research on shikonin and Boraginaceae plants, a research gap persists in the food industry and extraction technologies. This review addresses crucial aspects of shikonin deserving of further exploration. It begins by elucidating the attributes of the Boraginaceae plants and their medicinal traits in folklore. It proceeds to focus on the roots of the plant and its medicinal properties, followed by extraction procedures explored in the last fifteen years, emphasising the novel technologies that have been chosen to improve the yield extract while minimising extraction times. Furthermore, this review briefly outlines studies employing cell culture techniques to enhance in vitro shikonin production. Lastly, attention is directed towards research in the food industry, particularly on shikonin-loaded biodegradable films and the antioxidant activity of shikonin. This review concludes by summarising the future potential in food science and prominent research gaps in this field.

Redetermination of germacrone type II based on single-crystal X-ray data.

The extraction and purification procedures, crystallization and crystal structure refinement (single-crystal X-ray data) of germacrone type II, C15H22O, are presented. The structural results are compared with a previous powder X-ray synchrotron study [Kaduk et al. (2022 ▸). Powder Diffr. 37, 98-104], revealing significant improvements in terms of accuracy and precision. Hirshfeld atom refinement (HAR), as well as Hirshfeld surface analysis, give insight into the inter-molecular inter-actions of germacrone type II.

Exploring the potential of Beta Vulgaris L. Against thrombocytopenia: in vitro, in silico, phytochemicals, and antioxidant analysis

The purpose of this study was to assess anti- thrombocytopenia of beetroot extract using both in vitro and in silico methods. Additionally, antioxidant capacity, phenolic content, and flavonoid content of beetroot were determined. The extraction procedure was optimized by reflux method, the extracts obtained were examined to determine the Total Phenolic Content (TPC) and Total Flavonoid Content (TFC) using the Folin-Ciocalteu colorimetric and aluminum chloride methods, respectively. Furthermore, antioxidant capacity was assessed using the DPPH method, while betanin concentration was determined by thin-layer chromatography. This research approach encompasses the binding acticity of ligands and target proteins, the process of docking thrombopoietin receptor (TPOr) and betanin compound using Swissdock, and the examination of docking data using the USCF Chimera software. The studies revealed that the reflux-extracted beetroot extract had a total phenol concentration of 39.72 ± 2.56 mgGAE/g. The flavonoid concentration of beetroot extract obtained using reflux extraction was 5.47 ± 0.39 mg QE/g. The qualitative test conducted using thin layer chromatography yielded data indicating that the reflux-extracted extract tested positive for betanin. The reflux approach yielded an extract with antioxidant activity (IC50) of 95.71 μg/ml. The results of the molecular docking simulation showed that the betanin compound had a ΔG value of -8.1 Kcal/mol. It interacts with multiple amino acid residues, including LEU62, PRO63, ALA64, VAL65, ASP66, ARG138, THR139, THR140, ALA141, HIS142, ALA147, ILE148, LEU150, SER151, HIS154, PRO70, ARG71, ARG102, PHE104, PHE105, PRO106, and PHE126. An in vitro study demonstrated that the extract of Beta vulgaris L. has the ability to induce blood coagulation, indicating its potential as a haemostatic agent. Additionally, in silico investigations suggest that the betanin chemicals found in beetroot serve as TpoR agonists, and it can be concluded that betanin has antithrombocytopenia potential.

The benefits of experimental breeding research genotypes for the genetic resources of spring durum wheat

AbstractOur study aimed to incorporate 60 newly acquired spring durum wheat genotypes into the Prague Gene Bank collection, focusing on 54 experimental breeding research genotypes and their technological quality contributions for conservation and future use. We analyzed a total of 11 field and 6 technological parameters of grain quality. Additionally, we identified the composition of high molecular weight glutenin subunits (HMW-GSs) in 13 accessions with contrasting technological characteristics. Two different extraction procedures were employed to detect HMW-GSs: one based on total protein extraction and the other on gliadin pre-extraction. The tested parameters exhibited a significant range of variability, with the relative standard deviation ranging from 2.1% for starch content to 96.7% for the gluten index. Additionally, six breeding research genotypes exhibited high technological grain quality comparable to the two modern durum wheat cultivars. Two accessions: M90-99–2 and IG 142076 showed above-average Zeleny sedimentation values, probably positively influenced by the presence of HMW-GSs A1: (2*). Genotypes PI 675012 and IG 142039 displayed the highest grain stability in technological parameters. Both extraction methods also detected the specific subunit B1: (6 + 8*) in the genotype IG 142039. Preserving these genotypes thus represents a substantial expansion of genetic resources in the genebank.

Development of heat-assisted in-situ solvent formation liquid phase microextraction followed by derivatization for the simultaneous extraction of aliphatic amines from wastewater samples prior to gas chromatography-mass spectrometry

Herein, a cost-effective, rapid, and selective liquid phase microextraction procedure has been developed for the extraction of some aliphatic amines from sewage samples. The method was based on in-situ formation of chloroform as an extraction solvent into the sample solution followed by derivatization by butylchloroformate prior to gas chromatography- mass spectrometry. Chloroform is formed by the reaction of chloral hydrate and sodium hydroxide. The extraction procedure was accelerated by heating. Also heating decreases chloroform solubility in aqueous solution. To improve the analytical signals, derivatization of the analytes is done by butylchloroformate. The effect of major parameters on the extraction efficiency were studied and optimized. Under the optimized conditions, enrichment factor and extraction recovery were in the ranges of 259–296 and 78–89 %, respectively. Low limits of detection (0.08–0.12 ng mL−1) and quantification (0.28–0.41 ng mL−1), wide linear ranges, and relative standard deviations less than 6 % for intra −and inter-day precisions were acceptable. Lastly, the mentioned method was successfully performed to determine aliphatic amines in wastewater samples.

A planar graph cluster‐routing approach for optimizing medical waste collection based on spatial constraint

AbstractMedical Solid Wastes (MSWs) are major hazardous materials containing harmful biological or chemical compounds that present public and environmental health risks. The collection and transportation of waste are usually informed by optimized work‐balanced routing based on comprehensive spatial data in urban traffic networks, called a Vehicle Routing Problem (VRP). This may be unsuitable for MSWs as their special category means they impose additional complexity. The present article develops a planar graph‐based cluster‐routing approach for the optimal collection of MSWs informed by a Geospatial Information System (GIS). The problem is first formulated as a mixed integer linear program in road network spatial data, in the context of Tehran city. The work has two key aims: (i) to minimize the total routing cost of MSW collection and transfer to waste landfills; (ii) to balance workload across waste collectors. There are three main contributions of the proposed approach: (i) to simplify the large search space area by converting the road network to a planar graph based on graph theory, spatial parameters, and topological rules; (ii) to use a modified K‐means algorithm for clustering; (iii) to consider average traffic impacts in the clustering stage and momentary traffic in the route planning stage. A planar graph extraction procedure is applied to capture the network sketch (i.e., a directed graph) from the traffic roadway network. An iterative cluster‐first‐route‐second heuristic is employed to solve the proposed routing problem. This heuristic customizes a K‐means algorithm to determine the optimal number and size of clusters (i.e., routes). A Traveling Salesman Problem (TSP) algorithm is applied to regulate the optimal sequence of visits to medical centers. The experimental results show improvements in balancing collectors' workload (i.e., ~4 min reduction in the standard deviation of average travel time) with reductions in travel time (i.e., an average ~1 h for the entire fleet and ~4 min per route). These findings confirm that the proposed methodology can be considered as an approach for optimizing waste collection routes.

Targeted and untargeted screening of a plant extract library established from raw materials originating from Upper Austria

Plant extracts rich in phytochemicals are known for their health benefits. Plant extract library from edible plants obtained from the region of Upper Austria was prepared. Food grade extraction procedures were applied, and relevant physico-chemical parameters measured. A focus on polyphenolic compounds revealed a significant correlation between the total phenolic content (measured by a colorimetric assay) and the cumulated concentration of main individual polyphenols (measured by HPLC-DAD), demonstrating the comparability of these parameters. Targeted screening was performed by HPLC-FLD and −MS for the presence of phytomelatonin. 20 extracts were identified with concentrations of up to 1.4 µg/mL of this phytochemical, which attracts much attention from the food industry. Finally, chemometric methods were employed to cluster extracts based on their phenolic compound profile. This approach allows for an informed preselection of extracts without the need for comprehensive chemical analysis.

Optimized Method for High‐Quality RNA Extraction from Formalin‐Fixed Paraffin‐Embedded Tissues

AbstractRNA extraction from formalin‐fixed paraffin‐embedded tissues (FFPE) presents a notable challenge. Extracting RNA from FFPE tissues has been challenging due to RNA degradation and chemical bonding between RNA and proteins during the fixation process. This results in reduced concentration and quality of the extracted RNA from FFPE tissues, impacting subsequent downstream analyses. In this study, we present an optimized approach involves replacing the tissue temperature‐digestion step with tissue crushing and homogenization. RNA extraction was performed on 100 FFPE tissue blocks obtained from the archive of Pathology Department of Shiraz University of Medical Sciences. After deparafinization of the tissues, RNA was extracted using this modified method, and the results compared to those of a standard extraction procedure and commercial kits used for FFPE tissue. Then gel electrophoresis and Real time PCR were done to check the quality and integrity of the extracted RNA. The results show that the concentration of RNA obtained from this method was significantly (P value <0.0001) higher than the other methods. In conclusion, we have successfully introduced a modified method that enables the extraction of high‐quality and intact RNA from FFPE tissue. This method stands as a reliable option for molecular biology studies necessitating precise RNA extraction.

Enhancing Orthodontic Renewal and Retention Techniques: A Systematic Review.

Orthodontists have a variety of options available for retainers. Research in Orthodontics focuses on assessing outcomes important to clinicians; however, there is inconsistency in how these outcomes are selected and evaluated. This review sought to assess the effects of different orthodontic retainers on patients' quality of life (QoL). Various approaches were employed in this systematic review, and a thorough search was conducted across six databases. The review involved a comprehensive evaluation of six included studies, highlighting changes in dental structure post-treatment, emphasizing the role of extraction procedures and the quality of debonding in improving retention. The study identified key outcomes for orthodontic clinical trials, highlighting orthodontists' preferences for specific retainer types. Moreover, it discussed the impact of sociocultural influences on retention care. Involving patients actively in discussions about whether to end or extend the retention phase was deemed essential. Noteworthy improvements in occlusal outcomes were linked to extraction treatments. Gender and malocclusion severity influenced QoL before and after orthodontic treatment. The degree of improvement observed in the Class III malocclusion group was comparatively lower than that in the Class I and Class II groups. Orthodontic treatment was found to yield favorable psychological outcomes, as evidenced by notable enhancements in self-esteem and social engagement among individuals. Fixed appliances were shown to negatively affect oral health-related quality of life (OHRQoL), particularly for those with aesthetic and functional concerns. A consensus has been reached on the essential themes and outcomes that should be incorporated in clinical trials related to orthodontic retention for non-cleft and non-surgical cases.

Intelligence model for Alzheimer’s disease detection with optimal trained deep hybrid model

Alzheimer’s disease (AD), a neurodegenerative disorder, is the most common cause of dementia and continuing cognitive deficits. Since there are more cases each year, AD has grown to be a serious social and public health issue. Early detection of the diagnosis of Alzheimer’s and dementia disease is crucial, as is giving them the right care. The importance of early AD diagnosis has recently received a lot of attention. The patient cannot receive a timely diagnosis since the present methods of diagnosing AD take so long and are so expensive. That’s why we created a brand-new AD detection method that has four steps of operation: pre-processing, feature extraction, feature selection, and AD detection. During the pre-processing stage, the input data is pre-processed using an improved data normalization method. Following the pre-processing, these pre-processed data will go through a feature extraction procedure where features including statistical, enhanced entropy-based and mutual information-based features will be extracted. The appropriate features will be chosen from these extracted characteristics using the enhanced Chi-square technique. Based on the selected features, a hybrid model will be used in this study to detect AD. This hybrid model combines classifiers like Long Short Term Memory (LSTM) and Deep Maxout neural networks, and the weight parameters of LSTM and Deep Maxout will be optimized by the Self Updated Shuffled Shepherd Optimization Algorithm (SUSSOA). Our Proposed SUSSOA-based method’s statistical analysis of best values such as 57%, 53%, 28%, 25%, and 21% is higher than the other models like SSO, BMO, HGS, BRO, BES, and ISSO respectively.

A new sustainable filtration membrane extraction method based on nanoconfined liquid phase extraction: Determination of organochlorinated pesticides and pyrethroids in tea samples

BackgroundPesticides are used in agricultural production for prevent and control crop diseases and pests, but it is easy to cause excessive pesticides residues in agricultural products, polluting the environment and endangering human health. Due to their unmatched and sustainable capabilities, nanoextraction procedures are becoming every day more important in Analytical Chemistry. In particular, nanoconfined liquid phase extraction has shown extraction capabilities toward polar, medium polar, and/or nonpolar substances, which can be easily modulated depending on the nanoconfined solvent used. Furthermore, this “green” technique showed excellent characteristics in terms of recoveries, extraction time (≤1 min), reliability, and versatility. (97) ResultsIn this work, the advantages of this technique have been coupled with those of filtration membrane extraction, making use of carbon nanofibers (CnFs) growth on carbon microspheres (CμS). This substrate has been deposited on a filter, which combined with gas chromatographic mass spectrometry (GC-MS) analysis successfully employed for the nanoextraction of 30 pesticides (18 organochlorine and 12 pyrethroids) in tea samples. Under the optimized extraction conditions, the linear range with standard solutions was from 1 to 1000 ng mL−1 (R2 ≥ 0.99), the limit of detections in tea samples were in the range 0.56–17.98 μg kg−1. The accuracy of the developed method was evaluated by measuring the extraction recovery of the spiked tea samples, and recoveries between 74.41 % and 115.46 %. (119) SignificanceConsidering the versatility of nanoconfined liquid phase extraction and the functionality of the filtration membrane extraction procedure, this new extraction method can be considered a powerful candidate for automatized high-throughput analyses of real samples. (34)

Efficient removal of heavy metals from sewage sludge using a low-cost protic ionic liquid: Investigation of mechanism and ecological risk

Land utilization for the disposal of sewage sludge (SS) is an effective strategy, yet the existence of heavy metals (HMs) in the SS represents critical constraints to its implementation on a larger scale. By the principles of simple synthesis steps and low synthesis cost, a low-cost double cationic protic ionic liquid was produced in this study for HMs removal from SS. The influence of reaction time, protic ionic liquid to SS mass ratio, and reaction temperature on HM removal were thoroughly investigated. This result indicated that the integration of protic ionic liquid and heat treatment was efficacious in the efficient elimination of HMs. Under 60°C, 15 min, and protic ionic liquid: SS of 0.5, the removal efficiency of Zn, Fe, Ni, and Cd exceeded 80%, and Cr achieved a removal efficiency of up to 93%. The BCR sequential extraction procedure and calculation of the potential ecological risk index revealed a significant reduction in the ecological risk associated with the treated SS, transitioning from a high to a low-risk level. The alterations in elemental and chemical bonding within the solid phase of SS and changes in polysaccharide and fluorescence properties within the liquid phase of SS were investigated using redundancy analysis, two-dimensional correlation analysis, and parallel factor analysis. These findings suggest that dehydration, deamination, and decarboxylation reactions may be responsible for removing HMs within SS. These findings have a positive impact on further elucidating the effects of protic ionic liquid in SS pretreatment, thereby facilitating the efficient utilization of municipal SS resources.

Analysis of perfluorinated compounds in sewage sludge and hydrochar by UHPLC LTQ/Orbitrap MS and removal assessment during hydrothermal carbonization treatment

Wastewater treatment plants have been recognized as important sinks for per- and polyfluoroalkyl substances (PFAS) because of their ineffectiveness in removing them reflecting both water and sewage sludge discharge routes. Hydrothermal treatment represents an alternative technology for treating sludge to recover energy and other valuable products. In this study, 15 PFAS were determined in sludge and hydrochar substrates using sonication-solid phase extraction procedure and analyzed using LC-Orbitrap-High Resolution-MS/MS. The method was fully validated, exhibiting very good linearity, recoveries in the range of 48 to 126 %, low detection and quantification limits with expanded uncertainty and precision below 32 % and 21.9 %, respectively. The method was applied to sludge samples from the WWTP of Ioannina city (Greece), as well as to hydrothermally treated samples under various conditions. The most abundant PFAS were PFHxA (0.5–38.3 ng g−1) and PFOS (4.4–22.1 ng g−1). Finally, the hydrothermally treated sludge samples spiked with PFAS presented removal efficiencies for total PFAS of 86.9 %, 91.8 % and 95.7 % at three spiking levels namely 10, 50 and 200 ng g−1, respectively. Results indicated that PFCAs were almost completely removed, except for PFOA, while the concentrations of PFSAs increased in the produced hydrochar with the formation of several intermediates, as detected by HR-LC-MS/MS. The results of this study demonstrate the effect of hydrothermal treatment to the fate of PFAS in sewage sludge and contribute for further studies on design and scale up of hydrothermal carbonization technology as a management option for safer disposal of municipal wastewater sludge.

Comparison between Conventional Ageing Process in Barrels and a New Rapid Aging Process Based on RSLDE: Analysis of Bioactive Compounds in Spirit Drinks

“Aging” is a practice that allows alcoholic beverages to mature and gives them particular flavors and colors. In this context, oak or durmast wooden barrels are used in this process, thus providing different types of aging. This conventional process produces a slow enrichment of organic compounds in the spirit inside the barrels. Organic substances present in the internal part of the barrels slowly undergo the phenomenon of extraction by the liquid phase (solid–liquid extraction). In this work, a new procedure based on rapid solid–liquid dynamic extraction (RSLDE) was used to evaluate the potential of obtaining the effects of aging in spirits in shorter times than conventional methods. For this purpose, a comparison between two solid–liquid extraction techniques, RSLDE and conventional maceration, was made. Four water/ethanol 60:40 (v/v) model solutions were prepared and put in contact with medium-toasted chips using the two extraction procedures (conventional and non-conventional) and determining dry residue and total polyphenol content. Reversed phase high-performance liquid chromatography (RP-HPLC) analyses allowed the identification and quantification of furfural, ellagic acid and phenolic aldehydes (vanillin, syringaldehyde, coniferaldehyde and sinapaldehyde). The aging procedure with medium-toasted chips was tested on a young commercial grappa using maceration and RLSDE.

Combining EDTA-intercalated (Zn-Al) layered double hydroxides/graphite and two-phase hollow fiber for liquid phase microextraction of nonsteroidal anti-inflammatory drugs

This study synthesized and characterized layered double hydroxides (LDHs) intercalated with ethylenediaminetetraacetic acid(EDTA) to increase the basal spacing of electrosynthesized Zn-Al-LDHs on pencil graphite (PG). The characteristic verification of the Zn-Al-EDTA-LDH nanostructures was conducted utilizing Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive and X-ray analysis (EDS), and X-ray diffraction (XRD). To improve the extraction efficiency, Zn-Al-EDTA-LDHs as adsorbent in solid phase microextraction (SPME) fiber was combined with hollow fiber liquid–liquid phase microextraction (HF-LLPME) to investigate the extraction efficiency of HF-LLME@PG-SPME technique the chosen non-steroidal anti-inflammatory drugs (NSAIDs) from aqueous solution Several variables, comprising extraction time, desorption time, stirring rate, desorption volume, pH of donor phase, and salt effects were screened and optimized by performing placket-Burman design (PBD). After evaluating the extraction and desorption procedures under optimal conditions, NSAIDs analysis was performed employing high-performance liquid chromatography-ultraviolet detection (HPLC-UV). Compared to the most common clean-up and sample preparation methods, the current study focused on developing a greener analytical chemistry process due to reduced solvent consumption, cost-effectiveness, miniaturization and simplified design. The proposed method for NSAIDs exhibited a good linear dynamic range (LDRs) (1.00–200.00 µg/L) with a coefficient of determination of > 0.9956, low limits of detection (LODs) (0.26–0.29 µg/L) and acceptable limits of quantifications (LOQs) (0.86–0.96 µg/L). Relative standard deviations of 5.31 % could be determined. The absolute recoveries of the urine sample analyses could be obtained in a 89.91–97.61 % range and enrichment factors (EFs) (178.92 to 183.88). Investigations of the developed method were also conducted in various urine samples containing the selected drugs. As a result of the obtained recoveries, the method proved to be valuable and suitable to complicated biological samples.

User gait biometrics in smart ambient applications through wearable accelerometer signals: an analysis of the influence of training setup on recognition accuracy

Gait recognition can exploit the signals from wearables, e.g., the accelerometers embedded in smart devices. At present, this kind of recognition mostly underlies subject verification: the incoming probe is compared only with the templates in the system gallery that belong to the claimed identity. For instance, several proposals tackle the continuous recognition of the device owner to detect possible theft or loss. In this case, assuming a short time between the gallery template acquisition and the probe is reasonable. This work rather investigates the viability of a wider range of applications including identification (comparison with a whole system gallery) in the medium-long term. The first contribution is a procedure for extraction and two-phase selection of the most relevant aggregate features from a gait signal. A model is trained for each identity using Logistic Regression. The second contribution is the experiments investigating the effect of the variability of the gait pattern in time. In particular, the recognition performance is influenced by the benchmark partition into training and testing sets when more acquisition sessions are available, like in the exploited ZJU-gaitacc dataset. When close-in-time acquisition data is only available, the results seem to suggest re-identification (short time among captures) as the most promising application for this kind of recognition. The exclusive use of different dataset sessions for training and testing can rather better highlight the dramatic effect of trait variability on the measured performance. This suggests acquiring enrollment data in more sessions when the intended use is in medium-long term applications of smart ambient intelligence.

Development of a dispersive micro-solid phase extraction method based on using cobalamin as a green adsorbent for the extraction of Cd(II) and Pb(II) from oil samples

ABSTRACT A dispersive micro-solid phase extraction procedure using cobalamin as a green sorbent has been developed for the extraction of Cd(II) and Pb(II) ions from oil samples. At first, a desired amount of oil sample was dissolved in chloroform. Then, the specified amount of cobalamin was added and vortexed. After centrifuging, the separated solid particles were dissolved in nitric acid solution. Finally, the analytes were analysed by flame atomic absorption spectrometry. Effects of different analytical parameters such as amounts of sample and cobalamin, vortex time, complexing agent amount, type and volume of dissolving solvent, and temperature on the extraction efficiency of Pb(II) and Cd(II) ions were investigated and optimised. Under optimised conditions, calibration curves were established with the linear ranges of 1.5–150 μg Kg−1 for Cd(II) and 1–150 μg Kg−1 for Pb(II). The detection limits were found to be 0.48 and 0.34 µg Kg−1 along with extraction recoveries of 89.1% and 94.8% for Cd(II) and Pb(II) ions, respectively. The proposed method demonstrated good repeatability, with the relative standard deviation ranging from 3.8% to 4.1% (n = 6, C = 10 μg Kg−1 of each cation). Finally, the method was successfully applied to determine the concentrations of Cd(II) and Pb(II) ions in various oil samples.

Development and validation of an analytical method based on QuEChERS followed by UHPLC–ToF-MS for the determination of tropane alkaloids in buckwheat (Fagopyrum esculentum L.) and buckwheat products

A method was developed for the determination of tropane alkaloids (TAs), including atropine, scopolamine, anisodamine and homatropine in buckwheat and related products. This work presents an optimised methodology based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction procedure followed by ultra-high performance liquid chromatography combined with time-of-flight mass spectrometry for the determination of TAs (atropine, scopolamine, anisodamine and homatropine) in buckwheat samples. The analytical methodology was successfully validated, demonstrating good linearity, low limit of quantification, repeatability (RSDr < 15%), inter-day precision (RSDR < 19%) and recovery (74–113%). Finally, 13 commercial samples of buckwheat were analysed and the results demonstrated that they were in compliance with the current European regulations regarding TAs.

Spectrophotometric and DFT study of Germanium(IV) interaction with 6,7-dihydroxy-2,4-diphenyl-1-benzopyran-1-ium bromide in solutions: Room-temperature cloud point extraction and its analytical application

In the current study, a novel and fast procedure for room-temperature cloud point extraction of Germanium (VI) followed by spectrophotometric detection is developed. A 6,7-dihydroxy-2,4-diphenyl-1-benzopyran-1-ium bromide (DPBP) reagent was proposed for binding Ge (IV) into the extractable colored complex. The interaction of Ge (IV) with the reagent DPBP was studied using spectrophotometry and density functional theory (DFT) calculations. It was established that the complex stoichiometry is 1:2. It was shown that with the increase of the charge of the resulting complex, the Gibbs free energy of the complex formation increases considerably. This means that the formation of neutral species with cis- location of the hydroxyl ligands is the most preferable process. The cloud point phenomenon at room temperature was immediately initiated via ammonium benzoate. The calibration plot for Ge (IV) was obtained in the concentration range of 4–490 μg L−1 under optimized conditions: pH = 1, concentration of DPBP 1.8–2∙10-5 mol/L, 0.12 mol/L aqueous ammonium benzoate and 1 % (v/v) Triton X-100). The limit of detection is 1.2 μg L−1. The method was successfully applied to the determination of Ge(IV) traces in vegetable and rock samples.

Quantification of quaternary ammonium compounds by liquid chromatography-mass spectrometry: Minimizing losses from the field to the laboratory

Quaternary Ammonium Compounds (QACs) are widely used in household, medical and industrial settings. As a consequence, they are ubiquitously found in the environment. Although significant efforts have been put into the development of sensitive and reproducible analytical methods, much less effort has been dedicated to the monitoring of QACs upon sample storage and sample preparation. Here we studied the effect of storage, concentration, and extraction procedures on the concentrations of QACs in samples. Thirteen QACs selected amongst benzalkonium compounds (BACs), dialkyldimethylammonium compounds (DADMACs) and alkyltrimethylammonium compounds (ATMACs) were quantified in aqueous and solid samples using LC-MS/MS. Most QACs adsorbed on container walls could be recovered using a short washing step with MeOH containing 2 % v/v formic acid. Concentrations of QACs from aqueous solutions using solid phase extraction (SPE) with Strata-X cartridges and elution with acidified MeOH utilized to wash the emptied containers gave highly satisfactory recoveries (101–111 %). Good recoveries (89–116 %) were also obtained when extracting a spiked organic-rich synthetic soil using accelerated solvent extraction (ASE) with acidified MeOH at low solid/solvent ratio (0.4 g/20 mL). Applying the recommended methodologies to real samples collected from a Canadian wastewater treatment plant (WWTP) gave QAC concentrations in the ranges of 0.01–30 µg/L, < 1.2 µg/L, and 0.05–27 mg/kg for the influent, effluent and biosolids samples, respectively.