Direct infusion of lipid extracts into the ion source of a mass spectrometer is a well-established method for lipid analysis. In most cases, nanofluidic devices are used for sample introduction. However, flow injection analysis (FIA) based on sample infusion from a chromatographic pump can offer a simple alternative to shotgun-based approaches. Here, we describe important modification of a method based on FIA and tandem mass spectrometry (MS/MS). We focus on minimizing contamination of the FIA/MS both to render the lipidomic platform more robust and to increase its capacity and applicability for long-sequence measurements required in clinical applications. Robust validation of the developed method confirms its suitability for lipid quantitation in human plasma analysis. Measurements of standard human plasma reference material (NIST SRM 1950) and a set of plasma samples collected from kidney cancer patients and from healthy volunteers yielded highly similar results between FIA-MS/MS and ultra-high-performance supercritical fluid chromatography (UHPSFC)/MS, thereby demonstrating that all modifications have practically no effect on the statistical output. Newly modified FIA-MS/MS allows for the quantitation of 141 lipid species in plasma (11 major lipid classes) within 5.7 min. Finally, we tested the method in a clinical laboratory of the General University Hospital in Prague. In the clinical setting, the method capacity reached 257 samples/day. We also show similar performance of the classification models trained based on the results obtained in clinical settings and the analytical laboratory at the University of Pardubice. Together, these findings demonstrate the high potential of the modified FIA-MS/MS for application in clinical laboratories to measure plasma and serum lipid profiles.
- MeSH
- krevní plazma chemie MeSH
- lidé MeSH
- lipidomika * metody MeSH
- lipidy analýza MeSH
- průtoková injekční analýza MeSH
- tandemová hmotnostní spektrometrie * metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
This article describes the history, development, and current state of two analytical methods to which Czech scientists have made significant contributions. It describes the first steps of these methods in Czechoslovakia during the 1970s and 1980s, the development of the methods through innovation, and the establishment of cooperation with foreign scientists. Today, Czech scientists from the Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, and Institute of Analytical Chemistry of the Czech Academy of Sciences in Brno are among the major contributors to these fields of analytical chemistry. The milestones in the development and the prominent scientists mentioned in the individual chapters give a chance for a bright future for these methods, not only in the Czech Republic.
- MeSH
- dějiny 20. století MeSH
- dějiny 21. století MeSH
- elektroforéza kapilární * dějiny metody MeSH
- lidé MeSH
- průtoková injekční analýza MeSH
- Check Tag
- dějiny 20. století MeSH
- dějiny 21. století MeSH
- lidé MeSH
- Publikační typ
- historické články MeSH
- Geografické názvy
- Česká republika MeSH
A fully automated sequential injection system was tested in terms of its application in liberation testing, and capabilities and limitations were discussed for clotrimazole liberation from three semisolid formulations. An evaluation based on kinetic profiles obtained in short and longer sampling intervals and steady-state flux values were applied as traditional methods. The obtained clotrimazole liberation profile was faster in the case of Delcore and slower for Clotrimazol AL and Canesten cream commercial formulations. The steady-state flux values for the tested formulations were 52 µg cm-2 h-1 for Canesten, 35 µg cm-2 h-1 for Clotrimazol AL, and 7.2 µg cm-2 h-1 for Delcore measured in 4 min sampling intervals. A simplified approach for the evaluation of the initial rate based on the gradient between the second and third sampling points was used for the first time and was found to correspond well with the results of the conventional methods. A comparison based on the ratio of the steady-state flux and the initial rate values for Canesten and Clotrimazol AL proved the similarity of the obtained results. The proposed alternative was successfully implemented for the comparison of short-term kinetic profiles. Consequently, a faster and simpler approach for dissolution/liberation testing can be used.
An amperometric biosensor compatible with a flow injection analysis (FIA) for highly selective determination of acetaminophen (APAP) in a sample of human urine was developed. This biosensor is also suitable for use in the routine pharmaceutical practice. To prove this statement, two different commercially available pharmaceutical formulations were analyzed. This nano-(bio)electroanalytical device was made from a commercially available screen-printed carbon electrode covered by a thin layer of non-functionalized graphene (NFG) as amperometric transducer. A biorecognition layer was prepared from mushroom (Agaricus bisporus) tyrosinase (EC 1.14.18.1) cross-linked using glutaraldehyde, where resulting aggregates were covered by Nafion®, a known ion exchange membrane. Owing to the use of tyrosinase and presence of NFG, the developed analytical instrument is able to measure even at potentials of 0 V. Linear ranges differ according to choice of detection potential, namely up to 130 μmol L-1 at 0 V, up to 90 μmol L-1 at -0.1 V, and up to 70 μmol L-1 at -0.15 V. The first mentioned linear range is described by the equation Ip [μA] = 0.236 - 0.1984c [μmol L-1] and correlation coefficient r = 0.9987; this equation was used to quantify the content of APAP in each sample. The limit of detection of APAP was estimated to be 1.1 μmol L-1. A recovery of 96.8% (c = 25 μmol L-1, n = 5 measurements) was calculated. The obtained results show that FIA is a very selective method for APAP determination, being comparable to the chosen reference method of reversed-phase high-performance liquid chromatography.
- MeSH
- Agaricus enzymologie MeSH
- analýza moči přístrojové vybavení metody MeSH
- biosenzitivní techniky přístrojové vybavení metody MeSH
- design vybavení MeSH
- lidé MeSH
- limita detekce MeSH
- neopioidní analgetika moč MeSH
- paracetamol moč MeSH
- průtoková injekční analýza přístrojové vybavení metody MeSH
- tyrosinasa chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
A fully automated method for the determination of lovastatin in dietary supplements containing red yeast rice has been developed. It uses a sequential injection analysis system combined with solid-phase extraction applying highly selective molecularly imprinted polymer sorbent. A miniaturized column for on-line extraction was prepared by packing 4.5 mg of the sorbent in a 5.0 × 2.5-mm-i.d. cartridge, which was used in the flow manifold. Sequential injection analysis manifold enabled all steps of lovastatin extraction and continuous spectrophotometric detection at 240 nm. A limit of detection of 60 μg g-1, a limit of quantitation of 200 μg g-1, and a linear calibration range of 200-2000 μg g-1 were achieved. Intra-day and inter-day precision values (RSD) were ≤ 6.7% and ≤ 4.9%, respectively, and method recovery values of spiked red yeast rice extracts at 200, 1000, and 2000 μg g-1 concentration levels were 82.9, 95.2, and 87.7%. Our method was used for determination of lovastatin lactone in four dietary supplements containing red yeast rice as a natural source of lovastatin, also known as monacolin K. The extracted samples were subsequently analyzed by the reference UHPLC-MS/MS method. Statistical comparison of results (F test, t test, α = 0.05) obtained by both methods did not reveal significant difference. A substantial advantage of the new automated approach is high sample throughput thanks to the analysis time of 7.5 min, miniaturization via down-scaling the extraction column, and smaller sample and solvent consumption, as well as reduced generation of waste. Graphical abstract ᅟ.
- MeSH
- anticholesteremika analýza MeSH
- biologické přípravky analýza MeSH
- design vybavení MeSH
- extrakce na pevné fázi přístrojové vybavení metody MeSH
- limita detekce MeSH
- lovastatin analýza MeSH
- molekulový imprinting přístrojové vybavení metody MeSH
- polymery chemie MeSH
- potravní doplňky analýza MeSH
- průtoková injekční analýza přístrojové vybavení metody MeSH
- spektrofotometrie ultrafialová přístrojové vybavení metody MeSH
- tandemová hmotnostní spektrometrie přístrojové vybavení metody MeSH
- vysokoúčinná kapalinová chromatografie přístrojové vybavení metody MeSH
- Publikační typ
- časopisecké články MeSH
- validační studie MeSH
We report the first amperometric method for the simultaneous determination of tert-butylhydroquinone (tBHQ), propyl gallate (PG), and butylated hydroxyanisole (BHA) using flow injection analysis coupled to multiple-pulse amperometry. A sequence of potential pulses was selected in order to detect tBHQ, PG, and BHA separately in a single injection step at a glassy carbon electrode without the need of a preliminary separation. A mixture of methanol and 0.040M Britton-Robinson buffer was used both as a carrier solution and for dilution of analyzed solutions before injection. The method is precise (RSD < 5%, n = 10), fast (a frequency of 140 injections h-1), provides sufficiently low quantification limits (2.51, 1.45, and 0.85μmolL-1 for tBHQ, PG, and BHA, respectively) and can be easily applied without high demands on instrumentation. As a practical application, the determination of these antioxidants contained in commercial chewing gum samples was carried out by applying a simple extraction procedure.
The development of capacitively coupled contactless conductivity detection for the two-year period from mid-2014 to mid-2016 is covered in this review. This includes a survey of fundamental studies and further developments of the measuring technique reported as well as a discussion of new applications. These mostly concern capillary electrophoresis carried out in conventional capillaries as well as on microchip electrophoresis devices. The main focus is on the determination of small non-UV-absorbing organic ions and inorganic ions in different types of samples of clinical, nutritional or environmental interest. Outside of electrophoresis contactless conductivity detection is finding uses in detection in column chromatography, flow-injection analysis and industrial applications.
- MeSH
- anorganické látky analýza MeSH
- chromatografie metody MeSH
- design vybavení MeSH
- elektrická vodivost MeSH
- elektrody MeSH
- elektroforéza kapilární přístrojové vybavení metody MeSH
- elektroforéza mikročipová přístrojové vybavení metody MeSH
- ionty analýza MeSH
- lidé MeSH
- organické látky analýza MeSH
- počítačová simulace MeSH
- průtoková injekční analýza metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
A novel flow-programming setup based on the sequential injection principle is herein proposed for on-line monitoring of temporal events in cell permeation studies. The permeation unit consists of a Franz cell with its basolateral compartment mixed under mechanical agitation and thermostated at 37 °C. The apical compartment is replaced by commercially available Transwell inserts with a precultivated cell monolayer. The transport of drug substances across epithelial cells genetically modified with the P-glycoprotein membrane transporter (MDCKII-MDR1) is monitored on-line using rhodamine 123 as a fluorescent marker. The permeation kinetics of the marker is obtained in a fully automated mode by sampling minute volumes of solution from the basolateral compartment in short intervals (10 min) up to 4 h. The effect of a P-glycoprotein transporter inhibitor, verapamil as a model drug, on the efficiency of the marker transport across the cell monolayer is thoroughly investigated. The analytical features of the proposed flow method for cell permeation studies in real time are critically compared against conventional batch-wise procedures and microfluidic devices.
- MeSH
- automatizace metody MeSH
- biologický transport MeSH
- epitelové buňky chemie metabolismus MeSH
- kinetika MeSH
- lidé MeSH
- P-glykoprotein metabolismus MeSH
- průtoková injekční analýza přístrojové vybavení metody MeSH
- rhodamin 123 chemie metabolismus MeSH
- verapamil chemie metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
A low-pressure liquid chromatography system for the on-line quantification of caffeine loaded into lipid nanoparticles that permeates pig skin was developed. The apparatus includes a Franz diffusion cell with computer-controlled sampling that allows collection of acceptor solution with automatic compensation for sample withdrawing, and a C-18 reversed-phase monolithic column integrated in a typical Flow Injection Analysis (FIA) set-up where separation between caffeine and other matrix elements is performed before spectrophotometric quantification at 273 nm. Several parameters regarding chromatographic analysis (propulsion element, column length, mobile phase composition, and flow rate) were studied along with the establishment of the sampling procedure. Under the selected conditions (monolithic column Chromolith® RP-18 15 mm × 4.6 mm i.d., acetonitrile:water 10:90 (v/v), flow rate 0.45 mL min(-1)) a detection limit of 4 μM and RSD values for caffeine concentration <2% were achieved. High recovery values were obtained when Hepes buffer incubated as acceptor solution in presence of pig skin for 8 h was spiked with caffeine (103±5%). The developed system also accounts for low organic solvent consumption, low operating costs, low generation of waste and high sample throughput (24 h(-1)). Due to the real time automated sampling and high throughput, transdermal permeation profiles of nanoformulations can be established within a time frame seldom observed by conventional techniques.
- MeSH
- automatizace MeSH
- chromatografie s reverzní fází metody MeSH
- difuze MeSH
- kofein analýza chemie MeSH
- kůže metabolismus MeSH
- lidé MeSH
- limita detekce MeSH
- lipidy chemie MeSH
- nanočástice chemie MeSH
- nosiče léků chemie metabolismus MeSH
- permeabilita MeSH
- prasata MeSH
- průtoková injekční analýza MeSH
- reprodukovatelnost výsledků MeSH
- tlak * MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The review covers the progress of capacitively coupled contactless conductivity detection over the 2 years leading up to mid-2014. During this period many new applications for conventional CE as well as for microchip separation devices have been reported; prominent areas have been clinical, pharmaceutical, forensic, and food analyses. Further progress has been made in the development of field portable instrumentation based on CE with contactless conductivity detection. Several reports concern the combination with sample pretreatment techniques, in particular electrodriven extractions. Accounts of arrays of contactless conductivity detectors have appeared, which have been created for quite different tasks requiring spatially resolved information. The trend of the use of contactless conductivity measurements for applications other than CE has continued.
- MeSH
- analýza potravin přístrojové vybavení metody MeSH
- design vybavení MeSH
- elektrická vodivost MeSH
- elektroforéza kapilární přístrojové vybavení metody MeSH
- elektroforéza mikročipová přístrojové vybavení metody MeSH
- lidé MeSH
- monitorování životního prostředí přístrojové vybavení metody MeSH
- průtoková injekční analýza přístrojové vybavení metody MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
