Smartphone-based digital image colorimetry for the determination of total capsaicinoid content in chili pepper extracts.

A simple smartphone-based digital image colorimetry was proposed for the determination of total capsaicinoid content and the assessment of chili pepper pungency. The biobased solvent D-limonene was used for the first time to isolate analytes. Capsaicinoids were efficiently separated from chili pepper by solid-liquid extraction with D-limonene followed by partitioning of the analytes into the ammonium hydroxide solution to eliminate the matrix interference effect. For colorimetric detection of total capsaicinoid content, a selective chromogenic reaction was performed using Gibbs reagent (2,6-dichloroquinone-4-chloroimide). Measurements were performed using a smartphone-based setup and included image analysis with the program ImageJ. The limit of detection of the proposed procedure was 0.15 mg g-1. The intra-day repeatability did not exceed 10.0 %. The inter-day repeatability was less than 16.5 %. The comparison of the smartphone-based procedure with high-performance liquid chromatography showed satisfactory results.

Assessment of baby disposable diapers application for urine collection and determination of phthalate metabolites.

The baby disposable diapers were investigated as a sampling material for urine collection and validated for the evaluation of the exposure of children to xenobiotics. Phthalate metabolites detected in urine samples were chosen as proof-of-concept analytes. For the determination of phthalate metabolites in children's urine samples, high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was used. Two sampling approaches were compared, namely sterile containers and baby disposable diapers. Thirty urine samples from infants and toddlers were analyzed by both methods in parallel and the results were compared. It was found that for diaper sampling, lower concentrations of the metabolites were observed, however, the general distribution for particular metabolites remains the same for both methods. For most of the metabolites high determination coefficients were obtained, namely 0.9929 for MEHHP, 0.9836 for MMP, 0.9796 for MECPP, and 0.9784 for 2-cx-MMHP. For MEOHP the determination correlation coefficient was 0.9154, while for MBP was - 0.7771 and MEHP was - 0.5228. In general, for diaper sampling an underestimation for 2-cx-MMHP and MEOHP was observed, while for MMP diaper-based approach provides overestimation. However, the proposed procedure confirms the possibility of using baby disposable diapers as a material for the collection of urine samples for biomonitoring purposes and fast screening of phthalates exposure.

Plant-based meat substitute analysis using microextraction with deep eutectic solvent followed by LC-MS/MS to determine acrylamide, 5-hydroxymethylfurfural and furaneol.

For the analysis of plant-based meat substitutes and the determination of Maillard reaction products such as acrylamide, 5-hydroxymethylfurfural and furaneol, a novel and effective procedure based on hydrophobic natural deep eutectic solvent and liquid chromatography coupled with tandem mass spectrometry was developed for the first time. The 49 compositions of the deep eutectic solvents were designed and screened to select the most suitable option. The terpenoids eugenol and thymol in a molar ratio of 2:1 were selected as precursors for solvent formation, allowing effective extraction of the target analytes. The developed procedure comprised two main steps: extraction - in which the analytes are isolated from the solid sample due to the salting-out effect and pre-concentrated in the deep eutectic solvent, and back-extraction - in which the analytes are re-extracted into the formic acid solution for subsequent mass spectrometric detection. As the density of the aqueous phases changed during the extraction and back-extraction steps, the phenomenon of inversion of the coalesced organic phase was observed, which simplified the withdrawing of the phases. The linear range was 1-50 ng/mL for acrylamide, 10-1000 ng/mL for 5-hydroxymethylfurfural and 200-1000 ng/mL for furaneol with coefficients of determination above 0.9952. The developed method was fully validated and found recoveries were in the range 83-120%, with CVs not exceeding 4.9%. The method was applied to real sample analysis of pea-based meat substitutes.

Insights into baby disposable diapers sustainable application.

The sustainable use of baby disposable diapers is one of the issues currently being discussed to reduce the undesirable impact on the environment and improve the public's understanding of the proper use of diapers. This issue is a step toward promoting a cleaner, greener, and waste-less environment. In this article, the authors discuss options for a viable future for both people and the planet. We believe that it inspire others in the field of sustainable use of diapers as well as future education in this area. In addition, we believe that it will be a motivation for a researchers working in industry to be focused on the production of new, biodegradable baby diapers as well as on recycling baby diapers waste (for example as composite material for a structural and architectural component of the building).

Analytical applications of smartphones for agricultural soil analysis.

Soil is one of the most important farming resources. Appropriate managing of its quality promotes productive and sustainable agriculture. The valuable farm practice in soil quality managing is based on regular soil analysis with the aim of determining the exact amount of nutrients or other chemical, physical, and biological soil properties. Soil analysis usually requires sample collection at the desired sampling depth followed by sample delivery to chemical laboratories. However, laboratory analyses are resource-intensive and costly, and require a lot of time, effort, and equipment. A low-cost, fast, and effective alternative for soil quality control is the application of smartphones to perform chemical analyses directly in the field or on the farm. In this paper, an overview of recent developments on smartphone-based methodologies for agricultural purposes and portable evaluation of soil quality and its properties is presented. The discussion focuses on recent applications of smartphone-based devices for the determination of basic soil parameters, content of organic matter, mineral fertilizers, and organic or inorganic pollutants. Obvious advantages of using smartphones, such as convenience and simplicity of use, and the main shortcomings, such as relatively poor precision of the results obtained, are also discussed. The general trend shows the huge interest from researchers to move the technology into the field with the aim of providing cost-effective and rapid soil analysis. This paper can broaden the understanding of using smartphones for chemical analysis of soil samples, as it is a relatively new area and is expected to be developed rapidly.

Alkyl polyglucoside-based supramolecular solvent formation in liquid-phase microextraction.

The phenomenon of alkyl polyglucoside-based supramolecular solvent formation in the presence of alkyl carboxylic acid acted as coacervation agent was described for the first time. Various alkyl polyglucosides and carboxylic acids were studied as the amphiphiles and coacervation agents, respectively. A possible mechanism of the new supramolecular solvent formation was presented. The physico-chemical properties of the developed alkyl polyglucoside-based supramolecular solvents were investigated. The green liquid-phase microextraction approach with the use of alkyl polyglucoside-based supramolecular solvent was developed and applied to epinephrine (hormone and biomarker for the diagnosis of adrenal glands neoplastic diseases) separation and preconcentration from human urine samples prior to its chromatographic determination. Caprylyl/capryl glucoside was found to be the most effective supramolecular solvent precursor for microextraction of the epinephrine (extraction recovery 95%). The microliter amount of the heptanoic acid was required to induce coacervation process and phase separation. The reduced fluidity of alkyl polyglucoside-based supramolecular solvent under cooling was used to simplify the collection of the extract phase by decantation. The green supramolecular solvent obtained was less viscous then known nonionic surfactant-based solvents and as result more compatible with the high-performance liquid chromatography with fluorometric detection.

A surfactant-mediated microextraction of synthetic dyes from solid-phase food samples into the primary amine-based supramolecular solvent.

An effective and simple surfactant-mediated microextraction of synthetic dyes from solid-phase food samples into the primary amine-based supramolecular solvents is presented for the first time. The developed procedure involved two stages: (i) an isolation of dyes from a solid-phase food sample into a micellar solution of the primary amine; (ii) a preconcentration of the extracted dyes into the supramolecular solvent phase generated from the obtained micellar solution under a coacervation process. The microextraction procedure was applied for the determination of synthetic dyes in confectionery, dried fruits, and spices samples. The supramolecular solvent formed from aqueous micelle aggregates of 1-octylamine due to coacervation induced by thymol provided maximum extraction recovery values for synthetic dyes. In the proposed two-stage extraction procedure the micellar solution of primary amine was a media for analytes isolation from solid-phase and their followed preconcentration.

Chemical and computational strategy for design of "switchable" sorbent based on hydroxyapatite nanoparticles for dispersive micro-solid phase extraction of tetracyclines.

A challenging task in analytical chemistry is an application of renewable and natural materials for isolation of hazardous substances such as antimicrobial drugs from environmental samples. The energy-efficient scalable hydrothermal procedure to fabricate the eco-friendly "switchable" sorbent based on hydroxyapatite nanoparticles with in situ modified surface using a small amount of capping agents was developed. Sorbents characterization including the surface composition investigation via quantum-chemical calculation based on the original approach was provided. The sorbents demonstrated well expressed controllable surface switching and high values of the sorption and elution efficiency for tetracycline, oxytetracycline, and chlortetracycline achieved by simple change of the medium pH. These processes were thoroughly discussed based on the results of chemical and computational experiments. A simple and universal strategy for choosing a suitable sorbent for solid phase extraction of target analytes was proposed for the first time. It was shown that the developed eco-friendly sample preparation procedure with use of biocompatible sorbents could be applied both for removal of target analytes from sample matrix (water samples) as well as for the quantitative analytes determination after elution step. It is believed that the presented research is significant for the determination of different amphoteric analytes in wide variety of samples.

Microstructured optical fibers sensor modified by deep eutectic solvent: Liquid-phase microextraction and detection in one analytical device.

A sensitive optical sensor based on hollow core microstructure optical fibers modified with deep eutectic solvent was produced for the first time. An easy procedure for the modification of hollow-core microstructure optical fibers with deep eutectic solvent was developed. Deep eutectic solvents based on natural monoterpenoids and fatty acids were investigated for glass surface modification. The sensor was used for the determination of non-steroidal anti-inflammatory drugs (mefenamic acid, diclofenac, flurbiprofen and ketoprofen) in human urine samples. The mechanism of the sensor response was investigated and discussed. Liquid-phase microextraction of non-steroidal anti-inflammatory drugs was implemented in deep eutectic solvent phase supported in the inner surface of hollow-core microstructure optical fibers followed by transmission spectra measurement in one analytical device. The preconcentration step performed directly in the analytical device allowed to obtain high sensitivity and selectivity. The limits of detection calculated from the calibration plots based on 3σ were 3 µg L-1 for all target analytes.

Supramolecular solvents formation in aqueous solutions containing primary amine and monoterpenoid compound: Liquid phase microextraction of sulfonamides.

A phenomenon of supramolecular solvents formation in aqueous solutions containing primary amine and monoterpenoid compound is presented for the first time. A novel supramolecular solvent-based liquid phase microextraction was developed. In an aqueous phase primary amine formed isotropic solution due to formation of amphiphile supramolecular assembly. The phase separation was achieved by a coacervation process. The monoterpenoid phenol (thymol) acted as a coacervation agent and induced spontaneous in situ formation of tiny supramolecular solvent droplets. The applicability of the proposed microextraction procedure was demonstrated for the separation of sulfonamides from biological fluids (human plasma and serum). An obtained composition of supramolecular solvent (1-decylamine, thymol, water) promoted satisfactory extraction of polar analytes from aqueous phase. The calibration graphs were linear over the concentration ranges of 0.06-50 mg L-1 for sulfamethoxazole, sulfamethazine and sulfapyridine. The limit of detection calculated from the blank tests based on 3σ was 0.02 mg L-1 for all analytes. The total analysis time was 15 min.

Cobalt-doped hydroxyapatite nanoparticles as a new eco-friendly catalyst of luminol-H2O2 based chemiluminescence reaction: Study of key factors, improvement the activity and analytical application.

In this study, a novel catalyst based on hydroxyapatite doped by cobalt for chemiluminescence reaction of luminol oxidation by H2O2 was suggested for the first time. The catalyst nanoparticles were synthesized by a hydrothermal method and characterized by various methods including density functional theory calculations. The impact of nanoparticles sizes, surface composition, contact efficiency and crystallinity on chemiluminescence intensity were investigated. The maximum chemiluminescence intensity was obtained for polycrystalline nanoparticles. This phenomenon was studied in detail and applied for chemiluminescence analysis for the first time. The chemiluminescence determination of sulfonamides as model analytes was considered. The sensing was based on sulfonamides-dependent quenching of the chemiluminescence intensity in the presence of novel catalyst existed as an aqueous suspension.

Effect of surfactant coating of Fe3O4 nanoparticles on magnetic dispersive micro-solid phase extraction of tetracyclines from human serum.

A procedure for separation and preconcentration of tetracyclines from human serum samples involving magnetic dispersive micro-solid phase extraction was proposed. The extraction efficiency of different tetracyclines was improved with the use of the surfactant coated Fe3O4 magnetic nanoparticles. Sorption mechanism was presented, and the potential use of magnetic Fe3O4 nanoparticles coated with different surfactants for tetracyclines adsorption was demonstrated for the first time. The procedure involved nanoparticle floating in a liquid sample phase for analyte extraction followed by elution and determination by high performance liquid chromatography with diode array detection. Influence of the main involved parameters was studied, the system was dimensioned accordingly. The analytical curves were linear in the ranges of 0.25-10 mg L-1 for tetracycline and 0.10-10 mg L-1 for oxytetracycline or doxycycline. Limits of detection were estimated (IUPAC, 3 concept) as 0.08 mg L-1 for tetracycline, and 0.03 mg L-1 for oxytetracycline or doxycycline. The proposed procedure proved to be fast (10 min), simple (two stages), inexpensive (10 mg of nanoparticles) and was applied to human serum samples. Unlike previously synthesized nanoparticles for tetracyclines separation, the surfactant-coated Fe3O4 nanoparticles can be easily prepared with widely available and low-cost reagents. Moreover, elution of the analytes was accomplished in absence of organic solvents by an aqueous chelating agent solution.

An automated in-syringe switchable hydrophilicity solvent-based microextraction.

A fully automated in-syringe switchable hydrophilicity solvent-based microextraction approach was suggested for the first time. Di-(2-ethylhexyl)phosphoric acid was investigated as a novel switchable hydrophilicity solvent. The microextraction procedure implemented into a syringe pump included dissociation of the extractant in alkaline sample solution resulting in homogeneous solution formation followed by in situ organic phase generation by acidification and its separation. The microextraction procedure was applied to the HPLC-UV determination of antimicrobial drugs (sulfamethoxazole and sulfamethazine) in human urine samples as a proof-of-concept example. The calibration graphs were linear over the concentration ranges of 0.06-50 mg L-1 for sulfamethoxazole and 0.13-50 mg L-1 for sulfamethazine. The LODs calculated from the blank tests based on 3σ were 0.02 and 0.04 mg L-1 for sulfamethoxazole and sulfamethazine, respectively. The sample throughput was 12 samples h-1. The possibility of using the proposed procedure for assessing sulfamethoxazole/sulfamethazine acetylation in metabolic processes by individual human phenotypes was shown.

Stir membrane liquid phase microextraction of tetracyclines using switchable hydrophilicity solvents followed by high-performance liquid chromatography.

A novel approach for stir membrane liquid phase microextraction of tetracyclines from biological fluids was developed. The microextraction procedure assumed in situ formation of microdroplets of a hydrophobic medium-chain fatty acid (extraction solvent) from homogeneous sample solution containing water-soluble medium-chain fatty acid salt by acidification and simultaneous analytes extraction and organic phase separation into pores of stir membrane disk. Obtained large surface area between the extraction solvent and aqueous phase and high porosity of the membrane provided fast extraction and phase separation (extraction time - 5 min) and reducing extraction solvent volume to the order of several µL. The developed approach was applied for the HPLC-UV determination of tetracycline, oxytetracycline and chlortetracycline in biological fluids samples. The calibration graphs were linear over the concentration ranges of 0.1-100 mg L-1 for oxytetracycline, tetracycline and chlortetracycline. Regression coefficients were in the range from 0.994 to 0.998. The LOD values, calculated from the blank tests based on 3σ, were 30 µg L-1 for tetracycline, oxytetracycline and chlortetracycline. The RSD values expressing intra-day and inter-day repeatability were lower than 5% and 8%, respectively.

Homogeneous liquid-liquid microextraction based on primary amine phase separation: A novel approach for sample pretreatment.

A homogeneous liquid-liquid microextraction procedure based on primary amine phase separation was developed as a novel approach for the pretreatment of biological fluids. The procedure assumes primary amine dissolution in the aqueous sample phase, resulting in the creation of a homogeneous sample solution followed by phase separation and analyte extraction in the presence of a polar, water-miscible organic solvent. The phenomenon of primary amine phase separation from homogeneous aqueous solution in the presence of a polar, water-miscible organic solvent was studied in detail and applied for separation and preconcentration in chemical analysis for the first time. The suggested approach was used for the HPLC-UV determination of meropenem as a proof-of-concept analyte in human plasma and serum samples. Under optimal conditions, the detector response of meropenem was linear in the concentration range of 0.1-100.0 mg L-1. The limit of detection was calculated from a blank test based on 3σ, was 0.03 mg L-1.

In situ decomposition of deep eutectic solvent as a novel approach in liquid-liquid microextraction.

In this study, a novel approach for effective liquid-liquid microextraction based on deep eutectic solvent (DES) decomposition was suggested for the first time. It was established that DESs synthesized from tetrabutylammonium bromide and long-chain alcohols decomposed in aqueous phase resulting in in situ dispersion of organic phase and extraction of hydrophobic analyte(s). It this process long-chain alcohol acted as an extraction solvent and tetrabutylammonium bromide acted as a dispersive agent and promoted mass transfer between aqueous and organic phases as a salting out agent. Phenomenon of DES decomposition was studied in detail and applied for separation and preconcentration in chemical analysis for the first time. The developed approach was applied for 17ß-estradiol microextraction from transdermal gel samples as a proof-of-concept example. The results showed that the in situ dispersed organic phase obtained can provide efficient extraction of 17ß-estradiol with good extraction recovery (95 ±â€¯5%) and excellent reproducibility (6%). The reported approach proves to be fast, simple, and inexpensive.

A rotating cotton-based disk packed with a cation-exchange resin: Separation of ofloxacin from biological fluids followed by chemiluminescence determination.

A novel approach for green and simple solid-phase extraction of ionizable analytes using cation-exchange resin particles packed in a rotating cotton-based disk has been developed and utilized for the chemiluminescence determination of ofloxacin in biological fluids (serum and urine). The use of highly-available cation-exchange resin provided effective separation of analyte from complex sample matrixes and its elution by aqueous electrolyte solution without any organic solvents. Ofloxacin ionization in acidic sample solution allowed to provide effective separation of the analyte for subsequent chemiluminescence detection. The cotton-based disk was characterized by effective wettability. This feature promoted high mass transfer of the analyte to the cation-exchange resin surface at separation step and into elution solution at elution step. The sorption time was decreased to 10 min while the elution time was 5 min. Under the optimal conditions, the detector response for ofloxacin was linear in the concentration range from 9 × 10-8 to 3 × 10-5 mol L-1. The limit of detection, calculated from a blank test based on 3σ, was 3 × 10-8 mol L-1.

A chemiluminescence method for screening of fluoroquinolones in milk samples based on a multi-pumping flow system.

An automated and miniaturized chemiluminescence method for screening of fluoroquinolones in milk samples was proposed. The method was based on magnetic dispersive micro-solid phase extraction of analytes followed by the chemiluminescence determination of the total fluoroquinolones content using a multi-pumping flow system. In the developed method, Zr-Fe-C magnetic nanoparticles were used as an efficient sorbent for separation of fluoroquinolones from sample matrix. The chemiluminescence intensity obtained for Ce4+-SO32--Tb3+ chemiluminescence system was greatly increased in the presence of the analytes. Under the optimal conditions, the detector response for fluoroquinolones was linear in the concentration ranges from 5·10-9 to 1·10-6 mol L-1 with respect to fleroxacin. The limit of detection, calculated from a blank test based on 3σ, was 2·10-9 mol L-1 with respect to fleroxacin. The presented method demonstrated to be a good tool for available and cost-effective point-of-need screening fluoroquinolones in milk samples.

Tin oxide nanoparticles modified by copper as novel catalysts for the luminol-H2O2 based chemiluminescence system.

In this study, SnO2 nanoparticles modified by copper were found to greatly enhance the chemiluminescence intensity of the luminol-H2O2 system for the first time. The developed approach was applied for the determination of H2O2 as a proof-of-concept example.

An automated salting-out assisted liquid-liquid microextraction approach using 1-octylamine: On-line separation of tetracycline in urine samples followed by HPLC-UV determination.

An automated salting-out assisted liquid-liquid microextraction (SALLME) procedure based on a flow system was developed as new approach for pretreatment of complex sample matrix. In this procedure 1-octylamine was investigated as novel extractant for the SALLME. The procedure involved aspiration of the 1-octylamine and sample solution into a mixing chamber of a flow system followed by their air-bubble mixing resulting to isotropic solution formation. To provide phase separation a salting-out agent solution was added into the mixing chamber. After phase separation, the micellar 1-octylamine phase containing analyte was mixed with methanol and transported to a HPLC-UV system. To demonstrate the efficiency of the suggested approach, the automated procedure was applied for the HPLC-UV determination of tetracycline as a proof-of-concept analyte in human urine samples. Under the optimal conditions, the detector response of the analytes was linear in the concentration ranges of 0.5-20 mg L-1. The limit of detection, calculated from a blank test based on 3σ, was 0.17 mg L-1. The results demonstrate that the developed approach is highly cost-effective, simple and rapid.