BACKGROUND: Dried blood spot (DBS) sampling on cellulose cards suffers from varying blood haematocrit levels and from chromatographic effects, which have a direct impact on quantitative DBS analyses. Commercial volumetric microsampling devices were, therefore, introduced to mitigate these effects, however, these devices are not compatible with automated DBS processing systems and must be processed manually. RESULTS: Capillary electrophoresis (CE) instruments use fused-silica (FS) capillaries for precise and accurate liquid handling as well as for injection, separation, and quantitative analyses of liquid samples. These inherent features of an Agilent 7100 CE instrument were employed for the automated processing (elution and homogenization) of DBSs collected by hemaPEN® volumetric devices (2.74 μL of capillary blood per spot). The hemaPEN® samples were processed directly in CE vials by consecutive transfers of 56 μL of methanol and 14 μL of deionized water through the FS capillary in a sequence of 39 DBSs with repeatability of the liquid transfers better than 1.4 %. The resulting DBS eluates were homogenized by a quick air flush through the capillary and analyzed by the same capillary and CE instrument. Creatinine was selected as a clinically relevant model analyte and its endogenous concentrations in DBSs were determined by CE with capacitively coupled contactless conductivity detection (CE-C4D) in a background electrolyte solution consisting of 50 mM acetic acid and 0.1 % (v/v) Tween 20 (pH 3.0). The overall repeatability of the automated DBS processing and CE-C4D analyses of 39 DBSs was ≤7.1 % (peak areas) and ≤0.6 % (migration times), the calibration curve was linear in the 25-500 μM range (R2 = 0.9993) and covered all endogenous blood creatinine levels, the limit of detection was 5.0 μM, and sample throughput was >12 DBSs per hour. DBS ageing for 60 days and varying blood haematocrit levels (20-70 %) did not affect creatinine quantitative results (≤6.9 % for peak areas). Inter-capillary and inter-instrument repeatability was ≤7.7 % (peak areas) and ≤3.4 % (migration times) and demonstrated an excellent transferability of the proposed analytical concept among laboratories. SIGNIFICANCE AND NOVELTY: This contribution is the first-ever report on the use of a single off-the-shelf analytical instrument for fully automated analyses of DBSs collected by commercial volumetric microsampling devices and holds great promise for future unmanned quantitative DBS analyses.

• Klíčová slova
• Automation, Capacitively coupled contactless conductivity detection, Capillary electrophoresis, Creatinine, Dried blood spot, Volumetric microsampling,
• MeSH
• automatizace MeSH
• elektroforéza kapilární * metody   MeSH
• kreatinin krev   MeSH
• lidé MeSH
• test suché kapky krve * metody   přístrojové vybavení   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kreatinin MeSH

BACKGROUND: Microsampling of biological fluids followed by innovative sample pre-treatment reflects trends in bioanalytical chemistry. Volumetric absorptive microsampling (VAMS) enables exact whole blood volume collection and reduces the impact of hematocrit on the assay. In animal studies, it complies with the 3R principles (refine, reduce, replace). It allows for a gentle bleeding technique and a reduction in the number of laboratory animals by enabling ethically acceptable repeated blood collection from a single animal. Treating VAMS tips with electromembrane extraction (EME) in 96-well format offers a smart combination of non-invasive, low-volume blood collection with effective, environmentally friendly sample clean-up. RESULTS: This study introduces the first application of EME in 96-well format for direct isolation of analytes from 10 μL of whole blood collected onto a VAMS device. Doxorubicin, a clinically used anticancer drug also utilized in cancer/cardio-oncology research involving rodents, where microsampling offers important advantages, and its metabolite doxorubicinol, were selected as relevant analytes. The optimized EME yielded reproducible recoveries for both analytes regardless of hematocrit levels, different anticoagulants, or free multivalent ions in the sample. Compared to conventional VAMS tips treatment, EME reduced matrix effects, increased throughput, and an environmental friendliness of the extraction. The EME followed by the UHPLC-MS/MS assay was validated for both analytes in whole blood absorbed onto VAMS tips. The same protocol was implemented to treat plasma to determine the blood-to-plasma ratio of the analytes in the same experiments. The practical utility was demonstrated by analyzing real samples collected from the doxorubicin-treated nude mice. SIGNIFICANCE: The study offers a novel assay combining whole blood microsampling and sample clean-up in microextraction scale for preclinical pharmacokinetic studies with doxorubicin in rodents and for pharmacokinetic/pharmacodynamic modeling. This advancement in bioanalytical chemistry promotes scalable environmentally friendly procedures compatible with the 3R ethical principles in animal studies. Moreover, the concept of direct VAMS tips treatment with EME may also be easily translatable to clinical settings.

• Klíčová slova
• Anthracyclines, Doxorubicin, Doxorubicinol, Electromembrane extraction, Microextraction, Volumetric absorptive microsampling,
• MeSH
• doxorubicin * krev   analogy a deriváty   chemie   MeSH
• elektrochemické techniky metody   MeSH
• membrány umělé MeSH
• odběr vzorku krve metody   MeSH
• tandemová hmotnostní spektrometrie metody   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• doxorubicin * MeSH
• membrány umělé MeSH

We report the first vibrational circular dichroism (VCD) measurement of spatial heterogeneity in a sample using infrared (IR) microsampling. Vibrational circular dichroism spectra are typically measured using a standard IR cell with an IR beam diameter of 10 mm or greater making it impossible to investigate the spatial heterogeneity of a solid film sample. We have constructed a VCD sampling assembly with either 3 mm or 1 mm spatial resolution. An XY-translation stage was used to measure spectra at different spatial locations producing IR and VCD maps of the sample. In addition, a rotating sample stage was employed using a dual photoelastic modulator (PEM) setup to suppress artifacts due to linear birefringence in solid-phase or film samples. Infrared and VCD mapping of an insulin fibril film has been carried out at both 3 and 1 mm spatial resolution, and lysozyme films were mapped at 1 mm resolution. The IR spectra of different spots vary in intensity due primarily to sample thickness. The changes in the VCD intensity across the map largely correlate to corresponding changes in the IR map. Closer inspection of the insulin map revealed changes in the relative intensities of the VCD spectra not present in the parent IR spectra, which indicated differences in the degree of supramolecular chirality of the fibrils in the various spatial regions. For lysozyme films, in addition to different degrees of supramolecular chirality, reversal of the net fibril chirality was observed. The large signal-to-noise ratio observed at 1 mm resolution implies the feasibility of further increasing the spatial resolution by one or two orders of magnitude for protein fibril film samples.

• Klíčová slova
• VCD, VCD spatial map, Vibrational circular dichroism, film heterogeneity, insulin, lysozyme, microsampling, protein amyloid fibrils,
• MeSH
• amyloid analýza   chemie   MeSH
• artefakty MeSH
• cirkulární dichroismus metody   MeSH
• inzulin analýza   chemie   MeSH
• muramidasa analýza   chemie   MeSH
• počítačové zpracování signálu MeSH
• skot MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• vibrace MeSH
• zvířata MeSH
• Check Tag
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• amyloid MeSH
• inzulin MeSH
• muramidasa MeSH

We designed a concept of 3D-printed attachment with porous glass filter disks-SLIDE (Sweat sampLIng DevicE) for easy sampling of apocrine sweat. By applying advanced mass spectrometry coupled with the liquid chromatography technique, the complex lipid profiles were measured to evaluate the reproducibility and robustness of this novel approach. Moreover, our in-depth statistical evaluation of the data provided an insight into the potential use of apocrine sweat as a novel and diagnostically relevant biofluid for clinical analyses. Data transformation using probabilistic quotient normalization (PQN) significantly improved the analytical characteristics and overcame the 'sample dilution issue' of the sampling. The lipidomic content of apocrine sweat from healthy subjects was described in terms of identification and quantitation. A total of 240 lipids across 15 classes were identified. The lipid concentrations varied from 10-10 to 10-4 mol/L. The most numerous class of lipids were ceramides (n = 61), while the free fatty acids were the most abundant ones (average concentrations of 10-5 mol/L). The main advantages of apocrine sweat microsampling include: (a) the non-invasiveness of the procedure and (b) the unique feature of apocrine sweat, reflecting metabolome and lipidome of the intracellular space and plasmatic membranes. The SLIDE application as a sampling technique of apocrine sweat brings a promising alternative, including various possibilities in modern clinical practice.

• Klíčová slova
• apocrine sweat, lipidomics, mass spectrometry, microsampling, profiling,
• MeSH
• lidé MeSH
• lipidomika metody   MeSH
• lipidy analýza   MeSH
• metabolomika metody   MeSH
• odběr biologického vzorku * MeSH
• pot chemie   MeSH
• zdraví dobrovolníci pro lékařské studie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• lipidy MeSH

Oxycodone is a widely prescribed, full agonist opioid analgesic. As such, it is used clinically to treat different kinds of painful conditions, with a relatively high potential for doping practices in athletes. In this paper, different classic and innovative miniaturised matrices from blood and urine have been studied and compared, to evaluate their relative merits and drawbacks within therapeutic drug monitoring (TDM) and to implement new protocols for anti-doping analysis. Plasma, dried blood spots (DBS) and dried plasma spots (DPS) have been studied for TDM purposes, while urine, dried urine spots (DUS) and volumetric absorptive microsamples (VAMS) from urine for anti-doping. These sampling techniques were coupled to an original bioanalytical method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the evaluation and monitoring of the levels of oxycodone and its major metabolites (noroxycodone and oxymorphone) in patients under pain management and in athletes. The method was validated according to international guidelines, with good results in terms of precision, extraction yield and accuracy for all considered micromatrices. Thus, the proposed sampling, pre-treatment and analysis are attractive strategies for oxycodone determination in human blood and urine, with advanced options for application to derived micromatrices. Microsampling procedures have significant advantages over classic biological matrices like simplified sampling, storage and processing, but also in terms of precision (<9.0% for DBS, <7.7% for DPS, <7.1% for DUS, <5.3% for VAMS) and accuracy (>73% for DBS, >78% for DPS, >74% for DUS, >78% for VAMS). As regards extraction yield, traditional and miniaturised sampling approaches are comparable (>67% for DBS, >74% for DPS, >75% for DUS, >75% for VAMS). All dried matrices have very low volumes, leading to a significant advantage in terms of analysis feasibility. On the other hand, this also leads to a corresponding decrease in the overall sensitivity.

• Klíčová slova
• Anti-doping analysis, Bioanalysis, Blood and urine microsamples, Oxycodone, Therapeutic drug monitoring, Volumetric absorptive microsampling,
• MeSH
• chromatografie kapalinová metody   MeSH
• doping ve sportu metody   MeSH
• krevní plazma chemie   MeSH
• lidé MeSH
• miniaturizace metody   MeSH
• moč chemie   MeSH
• monitorování léčiv metody   MeSH
• morfinany krev   moč   MeSH
• odběr biologického vzorku metody   MeSH
• odběr vzorku krve MeSH
• oxykodon krev   moč   MeSH
• oxymorfon krev   moč   MeSH
• tandemová hmotnostní spektrometrie metody   MeSH
• tělesné tekutiny chemie   MeSH
• test suché kapky krve metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• morfinany MeSH
• noroxycodone MeSH Prohlížeč
• oxykodon MeSH
• oxymorfon MeSH

An off-the-shelf Agilent 7100 capillary electrophoresis (CE) instrument was employed for the automated processing and analysis of dried blood spots (DBSs) collected by Capitainer®B volumetric devices. Solutions for DBS elutions were transferred directly into CE vials through a separation capillary by the application of an auxiliary nitrogen gas connected to the external pressure line of the CE instrument. This allowed for liquid handling at pressures up to 15 bar and enabled the use of a single capillary for rapid DBS processing and efficient CE separations. The resulting DBS eluates were at-line injected into a short capillary end, which served for improved instrumental simplicity and short CE analysis times. The current set-up necessitated neither hardware nor software adjustments of the CE instrument, except for the connection of a gas cylinder to an in-built connector. The novel features presented in this study (DBSs with exact blood volumes, high external pressures, and short-end injections) were used for the automated determination of clinically relevant markers, phenylalanine (Phe) and tyrosine (Tyr), in DBS samples. Sensitive and selective Phe and Tyr quantification was achieved by CE-UV in 375 mM formic acid and 0.01 % (v/v) Tween 20 (pH 2.09) as a background electrolyte. The total processing and analysis times per one DBS were <1.5 and 4.5 min, respectively, in a sequence of 36 DBSs, and resulted in a sample throughput of >10 DBSs per hour. The intra- and inter-day repeatability values were better than 5.9 and 1.1 % RSD for peak areas and migration times, respectively, and calibration curves were linear in the 20-3000 μM (Phe) and 20-250 μM (Tyr) range (R2 ≥ 0.9973). The limits of detection were ≤2 μM and enabled the determination of endogenous Phe and Tyr concentrations as well as elevated Phe concentrations and Phe/Tyr ratios, which are the typical markers for neonatal phenylketonuria screening.

• Klíčová slova
• Amino acids, Automation, Capillary electrophoresis, Dried blood spots, Rapid analysis, Short-end injection, Volumetric microsampling,
• MeSH
• automatizace * MeSH
• časové faktory MeSH
• elektroforéza kapilární * metody   MeSH
• fenylalanin * krev   MeSH
• lidé MeSH
• limita detekce MeSH
• test suché kapky krve * metody   MeSH
• tyrosin * krev   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fenylalanin * MeSH
• tyrosin * MeSH

Plastic deformation in crystalline materials consists of an ensemble of collective dislocation glide processes, which lead to strain burst emissions in micro-scale samples. To unravel the combined role of crystalline structure, sample size and temperature on these processes, we performed a comprehensive set of strict displacement-controlled micropillar compression experiments in conjunction with large-scale molecular dynamics and physics-based discrete dislocation dynamics simulations. The results indicate that plastic strain bursts consist of numerous individual dislocation glide events, which span over minuscule time intervals. The size distributions of these events exhibit a gradual transition from an incipient power-law slip regime (spanning [Formula: see text] 2.5 decades of slip sizes) to a large avalanche domain (spanning [Formula: see text] 4 decades of emission probability) at a cut-off slip magnitude [Formula: see text]. This cut-off slip provides a statistical measure to the characteristic mean dislocation swept distance, which allows for the scaling of the avalanche distributions vis-à-vis the archetypal dislocation mechanisms in face-centered cubic (FCC) and body-centered cubic (BCC) metals. Our statistical findings provide a new pathway to characterizing metal plasticity and towards comprehension of the sample size effects that limit the mechanical reliability in small-scale structures.

• Publikační typ
• časopisecké články MeSH

Carbamazepine is an antiepileptic drug with a narrow therapeutic index, which requires an efficient method for blood level monitoring. Finger-prick dried blood spot (DBS) collection is an alternative microsampling technique, which is less invasive than conventional venipuncture. Paper-based molecularly imprinted-interpenetrating polymer networks (MI-IPN) were developed as blood collection devices, which allowed for selective on-spot microextraction of carbamazepine from DBS. A hybrid of homogeneous polystyrene and silica gel polymer was synthesized and coated on a Whatman® Grade 1 filter paper. Proteins and other interferences in the blood samples were eliminated by using the MI-IPN collection devices, and the resulting DBS extracts were suitable for direct injection into the capillary electrophoretic instrument. The lower limit of quantitation of 4 μg/mL in capillary blood was achieved by the sweeping-micellar electrokinetic chromatography method using a KCl-containing matrix, which was sufficient for the therapeutic drug monitoring purposes. Method accuracies were in the range of 88.4 ± 4.5% to 94.5 ± 2.7% with RSD values ≤ 5.1%. The developed paper-based MI-IPN provided superior extraction efficiencies (92.2 ± 2.5%) in comparison with commercially available DBS collection cards, i.e., Whatman® 903 protein saver card (59.8 ± 2.8%) and GenCollect™ 2.0 card (47.2 ± 1.4%). The paper-based MI-IPN devices for DBS collection and on-spot extraction were characterized by simple fabrication, low costs, disposability, and reduction in sample preparation steps, and their further developments might open new perspectives in clinical applications, such as in therapeutic drug monitoring. Graphical abstract.

• Klíčová slova
• Capillary electrophoresis, Carbamazepine, Dried blood spot, Molecularly imprinted polymer, Sol–gel,
• MeSH
• antikonvulziva krev   izolace a purifikace   MeSH
• elektroforéza kapilární metody   MeSH
• karbamazepin krev   izolace a purifikace   MeSH
• lidé MeSH
• mikroextrakce na pevné fázi metody   MeSH
• molekulárně imprintované polymery chemie   MeSH
• monitorování léčiv MeSH
• odběr vzorku krve metody   MeSH
• papír MeSH
• tandemová hmotnostní spektrometrie MeSH
• test suché kapky krve metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antikonvulziva MeSH
• karbamazepin MeSH
• molekulárně imprintované polymery MeSH

A new analytical protocol for identification of Prussian blue (PB) and indigo was proposed. Pigments useful for dating of artworks were detected by flow injection analysis/electrospray ionization mass spectrometry after alkalization of their suspensions in water, decomposition of PB to iron (III) hydroxide and hexacyanoferrate (II) and reduction of indigo to soluble leucoindigo using sodium dithionite. Limits of detection (PB 47 pg, indigo 59 pg) complied with requirements for analysis of microsamples of historical paintings. Potential of the developed method was proven in analysis of blue samples of two oil paintings from the 20(th) century. Further, PB was confirmed in a microsample from a painting of 'Crucifixion', St. Sebestian church on St. Hill in Mikulov, Czech Republic.

• Klíčová slova
• Prussian blue, electrospray, historical painting, indigo, mass spectrometry,
• MeSH
• barvicí látky analýza   chemie   MeSH
• dějiny 20. století MeSH
• ferrokyanidy analýza   chemie   MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací metody   MeSH
• indigotindisulfonát sodný analýza   chemie   MeSH
• malířství dějiny   MeSH
• nátěrové hmoty analýza   MeSH
• Check Tag
• dějiny 20. století MeSH
• Publikační typ
• časopisecké články MeSH
• historické články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• barvicí látky MeSH
• ferric ferrocyanide MeSH Prohlížeč
• ferrokyanidy MeSH
• indigotindisulfonát sodný MeSH

Diffusion coefficients for Na+ was measured in low-permeability samples (diameter of 3 cm and average length of 7 cm) from the deep disposal site of the Siberian Chemical Combine (SCC) using the end-diffusion technique. The direction of diffusion was perpendicular to the direction of bedding. Special equipment was designed and constructed for the experiment. Two types of concentration observations were used. For non-sorbing Na+, EC sensors and the length distribution of sorbed elements were used. The synthetic solution used in the experiments was a model of the low-activity contaminant of the SCC and consisted of NaNO3 (25 g/L) and nitrate compounds of Cs+, Ni2+, Co2+, and Sr2+ (100 mg/L each). The measured values of the effective diffusion coefficients De for Na+ from 1.92 × 10-11 to 1.70 × 10-10 m2/s. The microstructure was studied with X-ray microtomography for the same cores. Image shooting was performed on undisturbed microsamples with a size of 0.913 mm (7003 vox). Spatial correlation analysis was performed after the binarization of each obtained 3-D structure. This analysis showed that the spatial correlation scale of the indicator variogram is considerably smaller than the microsample length. Then, a numerical simulation of the Laplace equation with binary coefficients for each microsample was performed. The results were analysed in the form of a plot of the tortuosity versus the porosity. Pore-scale simulations show a nonlinear decrease in the tortuosity with decreasing porosity. Exponential values in the range between 1.8 and 2.4 were found by fitting this graph with Archie's model. Anisotropic tortuosity is also detected in the horizontal and vertical directions. The diffusion coefficients of non-sorbing Na+ measured in this study agree with those of the pore-scale diffusion simulation of the microtomography data.

• Klíčová slova
• Archie's law, Diffusion, Diffusion simulation, Diffusivity, Microtomography, Tortuosity,
• MeSH
• difuze MeSH
• permeabilita MeSH
• počítačová simulace MeSH
• poréznost MeSH
• půda * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• půda * MeSH