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
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
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
In this work, an application of an enzymatic reaction for the determination of the highly hydrophobic drug propofol in emulsion dosage form is presented. Emulsions represent a complex and therefore challenging matrix for analysis. Ethanol was used for breakage of a lipid emulsion, which enabled optical detection. A fully automated method based on Sequential Injection Analysis was developed, allowing propofol determination without the requirement of tedious sample pre-treatment. The method was based on spectrophotometric detection after the enzymatic oxidation catalysed by horseradish peroxidase and subsequent coupling with 4-aminoantipyrine leading to a coloured product with an absorbance maximum at 485 nm. This procedure was compared with a simple fluorimetric method, which was based on the direct selective fluorescence emission of propofol in ethanol at 347 nm. Both methods provide comparable validation parameters with linear working ranges of 0.005-0.100 mg mL(-1) and 0.004-0.243 mg mL(-1) for the spectrophotometric and fluorimetric methods, respectively. The detection and quantitation limits achieved with the spectrophotometric method were 0.0016 and 0.0053 mg mL(-1), respectively. The fluorimetric method provided the detection limit of 0.0013 mg mL(-1) and limit of quantitation of 0.0043 mg mL(-1). The RSD did not exceed 5% and 2% (n=10), correspondingly. A sample throughput of approx. 14 h(-1) for the spectrophotometric and 68 h(-1) for the fluorimetric detection was achieved. Both methods proved to be suitable for the determination of propofol in pharmaceutical formulation with average recovery values of 98.1 and 98.5%.
- MeSH
- ampyron metabolismus MeSH
- automatizace MeSH
- fluorescence MeSH
- fluorometrie metody MeSH
- indikátory a reagencie metabolismus MeSH
- křenová peroxidasa metabolismus MeSH
- propofol analýza MeSH
- průtoková injekční analýza metody MeSH
- spektrofotometrie ultrafialová metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A proof of concept of a novel pervaporation sequential injection (PSI) analysis method for automatic non-chromatographic speciation analysis of inorganic arsenic in complex aqueous samples is presented. The method is based on hydride generation of arsine followed by its on-line pervaporation-based membrane separation and CCD spectrophotometric detection. The concentrations of arsenite (As(III)) and arsenate (As(V)) are determined sequentially in a single sample zone. The leading section of the sample zone merges with a citric acid/citrate buffer solution (pH 4.5) for the selective reduction of As(III) to arsine while the trailing section of the sample zone merges with hydrochloric acid solution to allow the reduction of both As(III) and As(V) to arsine at pH lower than 1. Virtually identical analytical sensitivity is obtained for both As(III) and As(V) at this high acidity. The flow analyzer also accommodates in-line pH detector for monitoring of the acidity throughout the sample zone prior to hydride generation. Under optimal conditions the proposed PSI method is characterized by a limit of detection, linear calibration range and repeatability for As(III) of 22 μg L(-1) (3sblank level criterion), 50-1000 μg L(-1) and 3.0% at the 500 μg L(-1) level and for As(V) of 51 μg L(-1), 100-2000 μg L(-1) and 2.6% at the 500 μg L(-1) level, respectively. The method was validated with mixed As(III)/As(V) standard aqueous solutions and successfully applied to the determination of As(III) and As(V) in river water samples with elevated content of dissolved organic carbon and suspended particulate matter with no prior sample pretreatment. Excellent relative recoveries ranging from 98% to 104% were obtained for both As(III) and As(V).
- MeSH
- arseničnany izolace a purifikace MeSH
- arsenikové přípravky chemie MeSH
- arsenitany izolace a purifikace MeSH
- chemické látky znečišťující vodu izolace a purifikace MeSH
- kalibrace MeSH
- koncentrace vodíkových iontů MeSH
- kyselina citronová chemie MeSH
- limita detekce MeSH
- průtoková injekční analýza metody MeSH
- řeky chemie MeSH
- spektrofotometrie přístrojové vybavení metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Equipment for fast and accurate detection of organophosphate nerve agents is developed and tested. The method is based on the spectrophotometric monitoring of the enzyme activity of butyrylcholinesterase after its contact with air in a special absorption unit (a “scrubber”) developed for the purpose. The scrubber was made from a glass tube filled with glass beads (diam. 3 mm) and filled with approx. 5 ml of butyrylcholinesterase in a phosphate buffer of pH 7.4. The air sample was bubbled through this solution for 20 s at a flow rate of 80 l hour-1. Thereafter 8 microl of the enzyme solution were aspirated into the micro-SIA-LOV analyzer and the activity of the enzymes were evaluated by using Ellman’s reagent, i.e. 2.5 mmol l-1 butyrylthiocholine iodide and 0.25 mmol 5,5’-dithiobis (2-nitrobenzoic acid). The absorbance of the coloured reaction product was measured at 412 nm after the reaction time of 60 s. The residue of the absorption liquid was washed away from the absorber and the system was washed with the enzyme solution prior to next analysis. The contaminated air caused partial inhibition of the enzyme activity of the absorption liquid. The activity of the contaminated sample was compared with the activity of the unaffected enzyme (blank measurement). The analysis was controlled by two PCs. The effect of the concentration of analyte in the absorption liquid on the enzyme activity was tested for 10-5-10-9 mol l-1 sarin. A single analysis (including the absorption step) took <130 s.
- MeSH
- butyrylcholinesterasa MeSH
- chemické bojové látky MeSH
- cholinesterasové inhibitory analýza MeSH
- design vybavení MeSH
- laboratorní automatizace přístrojové vybavení MeSH
- organofosforové sloučeniny analýza MeSH
- průtoková injekční analýza * metody přístrojové vybavení statistika a číselné údaje MeSH
- sarin * analýza MeSH
- sekvenční analýza metody MeSH
- spektrofotometrie metody MeSH
- zdravotnické prostředky MeSH
- znečištění ovzduší * analýza statistika a číselné údaje MeSH
- Publikační typ
- hodnotící studie MeSH
- práce podpořená grantem MeSH
Flow injection analysis (FIA) is an analytical method where the reaction mixture is injected into flow of liquid. The reaction product is monitored by a suitable detector such as ultraviolet/visible (UV/VIS) spectrophotometric or electrochemical detector. Mass spectrometric detectors (MS) are coming to be a standard equipment of analytical laboratories in the present time. This work is focused on application of FIA-MS instrumentation for monitoring of Ellman's reaction where both reactants (acetylthiocholine and 5,5’-dithiobis-2-nitrobenzoic acid, DTNB) and the reaction product (5-mercapto-2-nitrobenzoic acid) are monitored. This reaction is usually used for monitoring of acetylcholinesterase and butyrylcholinesterase. Due to its simplicity, the developed method is generally applicable for monitoring of enzymatic reactions of cholinesterases. The main advantage of this method is high selectivity and reduction of influence of compounds, which are reacting with DTNB, resulting in a color product of Ellman's reaction.
