A sensitive capillary electrophoretic method featuring spectrophotometric detection using a commercial Z-cell was devised for the assay of 8-hydroxy-2'-deoxyguanosine (8OHdG) in human urine. Solid-phase extraction (SPE) based on hydrophilic-lipophilic-balanced RP sorbent was utilized for urine sample pretreatment and analyte preconcentration. The separation was carried out in conventional fused-silica capillaries employing a Z-cell with hydrodynamic sample injection (at 50 mbar for 12 s). The BGE (pH* 9.2, adjusted with 1 M NaOH) contained 0.15 M boric acid and 10% v/v ACN. The detection wavelength was 282 nm. The calibration curve for 8OHdG (measured in spiked urine) was linear in the range 10-1000 ng/mL; R(2) = 0.9993. The LOD was 3 ng/mL (11 nmol/L) of 8OHdG. Determination of the 8OHdG urinary levels was possible even in healthy individuals.

• Klíčová slova
• 8-Hydroxy-2′-deoxyguanosine, CE, Oxidative stress, Urine,
• MeSH
• 8-hydroxy-2'-deoxyguanosin MeSH
• deoxyguanosin analogy a deriváty   chemie   moč   MeSH
• elektroforéza kapilární metody   MeSH
• extrakce na pevné fázi metody   MeSH
• lidé MeSH
• limita detekce MeSH
• lineární modely MeSH
• reprodukovatelnost výsledků MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 8-hydroxy-2'-deoxyguanosin MeSH
• deoxyguanosin MeSH

Turbidimetric method with spectrophotometric detection of changes in density of test bacteria S. aureus strain SA 812 for determination of bacteriolytic activity of lysostaphin was employed. Results of two evaluations are compared: (1) calculation of the relative value of turbidity decrease on the basis of the difference of absolute values of A540 at the beginning of reaction and after the incubation period, (2) following of time changes in A540 by monitoring the course of reaction directly in the constant-temperature cuvette of the spectrophotometer at 37 degrees C. Both arrangements yielded identical results, within the significance level of 0.05. With concentrated samples both methods yield reliable results; with diluted samples the accuracy of the "absolute" method decreases together with decreasing lysostaphin concentration much faster than with the "registration" method. The registration method makes it possible to detect even minute amounts of the lytic enzyme and thus to distinguish the values of activity in dilute samples even when data obtained by means of the "absolute" method cannot be considered as reliable. A unit of bacteriolytic activity can be expressed from the kinetic curve as an amount of enzyme preparation causing delta A540/min = 0.01.

• MeSH
• bakteriolýza účinky léků   MeSH
• fluorometrie MeSH
• lysostafin farmakologie   MeSH
• nefelometrie a turbidimetrie * metody   MeSH
• spektrofotometrie * metody   MeSH
• Staphylococcus aureus účinky léků   MeSH
• teplota MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• lysostafin MeSH

In the proposed procedure, the determination of bopindolol using a sequential injection technique (SIA) with spectrophotometric detection at 560 nm is described. The new method of determination is based on the color reaction of the indole group in the molecule of bopindolol with 4-dimethylaminobenzaldehyde (Ehrlich's reagent) in acidic medium with production of a violet water-soluble complex. Due to the kinetic standpoint of reaction, the "stopped flow" technique with mixing coil between the valve and detector was tested and optimized. The proposed SIA system was used for the direct determination of bopindolol in tablets, negative effects of interfering substances (excipients of tablets) were not observed. The selectivity of the proposed method of determination was tested in the presence of seven interfering substances from the group of beta-blockers with good results. The interference effect was observed only in the presence of pindolol. The sample throughput with stopped flow technique was 40 samples per hour. Bopindolol was determined in the linear range from 1 to 10 microg ml(-1), RSD was less than 1% (n=10), with limit of detection (3sigma) 0.1 microg ml(-1) and limit of quantification 0.5 microg ml(-1). Obtained results were compared with conventional HPLC method, both analytical techniques were in good agreement.

• MeSH
• benzaldehydy chemie   MeSH
• beta blokátory analýza   MeSH
• pindolol analogy a deriváty   analýza   MeSH
• průtoková injekční analýza přístrojové vybavení   metody   MeSH
• reprodukovatelnost výsledků MeSH
• spektrofotometrie MeSH
• tablety analýza   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• benzaldehydy MeSH
• beta blokátory MeSH
• bopindolol MeSH Prohlížeč
• p-dimethylaminobenzaldehyde MeSH Prohlížeč
• pindolol MeSH
• tablety MeSH

Determination of free cyanide (fCN) is required for various industrial, environmental, food, and clinical samples. Enzymatic methods are not widely used in this field despite their selectivity and mild conditions. Therefore, we present here a proof of concept for new spectrophotometric enzymatic assays of fCN. These are based on the hydrolysis of fCN affording the readily detectable NADH. fCN is hydrolyzed either in one step by cyanide dihydratase (CynD) or in two steps by cyanide hydratase (CynH) and formamidase (AmiF). An advantage of the latter route is the higher activity of CynH and AmiF compared to CynD. In both cases, the resulting formate is then transformed by an NAD-dependent formate dehydrogenase (FDH). The NADH thus formed is quantified colorimetrically using a known method based on a reduction of a tetrazolium salt (WST-8) with NADH. The developed assays of fCN are selective except for formic acid interference, proceed under mild conditions, and, moreover, fCN is detoxified during the reactions. The assays proceeded in a microtiter plate format. The limit of detection (LOD) and the limit of quantification (LOQ) were lower for the three-enzyme (CynH-AmiF-FDH) method (7.00 and 21.2 µmol/L, respectively) than for the two-enzyme (CynD-FDH) method (10.7 and 32.4 µmol/L, respectively). In conclusion, the new fCN assays presented in this work are selective, high-throughput, do not require harsh conditions, and use only small amounts of chemicals and enzymes.

• Klíčová slova
• Cyanide dihydratase, Cyanide hydratase, Enzymatic assays, Formamidase, Formate dehydrogenase, Free cyanide,
• MeSH
• dehydratasy chemie   metabolismus   MeSH
• enzymatické testy * metody   MeSH
• hydrolýza MeSH
• kolorimetrie metody   MeSH
• kyanidy * analýza   metabolismus   MeSH
• limita detekce MeSH
• NAD chemie   MeSH
• spektrofotometrie metody   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dehydratasy MeSH
• kyanidy * MeSH
• NAD MeSH

Procedures for the extraction-spectrophotometric determination of tris(2-chloroethyl)amine, an alkylating agent known as a drug as well as a chemical warfare agent (nitrogen mustard HN-3), with 7 acid-base indicators of a triphenylmethane lactone type, phthaleins, were developed. Representatives of phthaleins without an oxygen bridge (thymolphthalein, o-cresolphthalein, naphtholphthalein) and with an oxygen bridge (fluorescein, 2',7'-dichlorofluorescein, eosin B and eosin Y) were used. The methods were based on the formation of ion pair complexes. Chloroform was used as a non-polar solvent for an extraction. The conditions to determine were optimized for the optimal pH of the buffer and the concentration of a phthalein as a reagent. The dependence on the reaction time in a water phase and the stoichiometry of extraction products were studied. The detection limits and the limits of the determination of separate procedures and conditional extraction constants were determined. Comparison with the spectrophotometric method of the group determination of alkyl halides and acyl halides using alkaline ethanol-water solution of thymolphthalein, the so-called T-135 agent, was conducted. While studying the selectivity, the possible interference of bis(2-chloroethyl)sulphide and 3 nitrogen mustards in the proposed procedures were verified. Copyright © 2016 John Wiley & Sons, Ltd.

• Klíčová slova
• nitrogen mustard, phthalein, spectrophotometry, tris(2-chloroethyl)amine,
• MeSH
• alkylační látky analýza   izolace a purifikace   MeSH
• chemické bojové látky analýza   izolace a purifikace   MeSH
• fenolftaleiny chemie   MeSH
• koncentrace vodíkových iontů MeSH
• limita detekce MeSH
• pufry MeSH
• sloučeniny dusíkatého yperitu analýza   izolace a purifikace   MeSH
• spektrofotometrie metody   MeSH
• voda analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• Názvy látek
• 2,2',2''-trichlorotriethylamine MeSH Prohlížeč
• alkylační látky MeSH
• chemické bojové látky MeSH
• fenolftaleiny MeSH
• pufry MeSH
• sloučeniny dusíkatého yperitu MeSH
• voda MeSH

A simple and reproducible method for the determination of roxithromycin in human plasma is presented. This method is based on liquid-liquid extraction with hexane-isoamylalcohol (98:2, v:v) and reversed-phase chromatography with spectrophotometric detection at 220 nm. The mobile phase consists of methanol-15 mM dihydrogen potassium phosphate (70:30, v:v), pH of the aqueous part of the mobile phase is 6.0. The column is operated at 60 degrees C. Clarithromycin is used as the internal standard. The limit of quantitation is 0.5 microg/ml and the calibration curve is linear up to 30 microg/ml. Within-day and between-day precision expressed by relative standard deviation is less than 5% and inaccuracy does not exceed 9%. The assay was used for pharmacokinetic studies.

• MeSH
• antibakteriální látky krev   farmakokinetika   MeSH
• lidé MeSH
• reprodukovatelnost výsledků MeSH
• roxithromycin krev   farmakokinetika   MeSH
• senzitivita a specificita MeSH
• spektrofotometrie ultrafialová MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky MeSH
• roxithromycin MeSH

Poly(butyl methacrylate) monolithic columns were prepared by thermally initiated radical polymerization in fused-silica capillaries of 320 microm i.d. The prepared monolithic columns were tested by capillary liquid chromatography (CLC) combined with a UV-VIS spectrophotometric detector. The influence of the detection configuration (i.e., on-column and external-cell detection modes) on the performance of the chromatographic system was investigated. In the on-column detection mode within the monolith, the detection window was located inside the column section filled with the monolith. With the on-column detection configuration after the monolith, the detection window was positioned just behind the column section containing the monolith. Using the external-cell detection mode, an additional detection capillary, provided with a detection window defining the external-cell, was connected to the monolithic capillary column. These detection modes were critically compared in terms of the principal chromatographic parameters of the system involving the prepared monolithic capillary columns.

• MeSH
• chromatografie kapalinová přístrojové vybavení   metody   MeSH
• senzitivita a specificita MeSH
• spektrofotometrie metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Heparin inhibits transport of electrons from reduced cytochrome c to cytochrome c oxidase. The effect is due to the interaction of heparin with cytochrome c. It has been observed that binding of heparin to the reduced or oxidized cytochrome c changes the spectrum of cytochrome c at the Soret region. Affinity chromatography of heparin in cytochrome c immobilized to thiol-Sepharose shows that commercial heparin is eluted in the low-affinity and high-affinity fractions. Both participate in the interaction with cytochrome c. Polylysine induces decay of the cytochrome c-heparin complex.

• MeSH
• chromatografie afinitní MeSH
• cytochromy skupiny c chemie   metabolismus   MeSH
• enzymy imobilizované MeSH
• heparin metabolismus   MeSH
• oxidace-redukce MeSH
• polylysin farmakologie   MeSH
• respirační komplex IV antagonisté a inhibitory   metabolismus   MeSH
• spektrální analýza MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cytochromy skupiny c MeSH
• enzymy imobilizované MeSH
• heparin MeSH
• polylysin MeSH
• respirační komplex IV MeSH

Butyrylcholinesterase (BChE) is an enzyme presented in quite high level in blood plasma where it participates in detoxification reactions. Due to fact that the enzyme is constituted in livers, it is a marker of liver parenchyma function. It can be used for diagnosis of poisoning for e.g., nerve agents or carbofuran and intoxication by some drugs such as rivastigmine. The present experiment is devoted for the creation of new spectrophotometric tests for assay of BChE activity in biological samples. Standard Ellman's method was compared with use of 2,6-dichloroindophenol acetate and indoxylacetate as chromogenic substrates. Maximal velocities and Michaelis constants were calculated for the substrates. Considering calibration, 2,6-dichloroindophenol acetate provided the lowest limit of detection: 1.20 × 10(-9)kat and a long linear range. All methods were verified using pooled human plasma samples and tested for potential interferents. 2,6-dichloroindophenol acetate is recommended as suitable substrate for BChE assay in clinical diagnostics.

• MeSH
• 2,6-dichlorindofenol chemie   MeSH
• acetáty MeSH
• biologické markery krev   MeSH
• butyrylcholinesterasa krev   MeSH
• indoly chemie   MeSH
• játra enzymologie   MeSH
• kinetika MeSH
• lidé MeSH
• limita detekce MeSH
• spektrofotometrie metody   MeSH
• substrátová specifita MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2,6-dichlorindofenol MeSH
• acetáty MeSH
• biologické markery MeSH
• butyrylcholinesterasa MeSH
• indoly MeSH
• indoxyl acetate MeSH Prohlížeč

Butyrylcholinesterase (BChE) is an enzyme abundantly constituted in the livers and released into blood where it is soluble. It may be found in the both plasma and serum. BChE can serve as a biochemical marker. BChE activity is typically measured by spectrophotometric Ellman's method. In the present work, voltammetric assay of cholinesterasemia is proposed as a simple and reliable method. In the experiments described here, limits of detections 4.57 pkat for the spectrofotometric test and 1.14 pkat for the voltammetric assay were determined. Interference caused by acetylcholinesterase (AChE) and organic solvents was characterized and counter measurement to the AChE caused interference was proposed. Finally, the both methods were correlated one to each other using mouse plasma spiked with carbofuran resulting in a promising coefficient of determination. In a conclusion, the voltammetric assay seems to be reliable and suitable for routine performance.

• Klíčová slova
• Acetylcholinesterase, Butyrylcholinesterase, Electrochemistry, Ellman's assay, Liver function test, Sensor, Voltammetry,
• MeSH
• butyrylcholinesterasa krev   MeSH
• limita detekce MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• referenční standardy MeSH
• reprodukovatelnost výsledků MeSH
• spektrofotometrie metody   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• butyrylcholinesterasa MeSH