- MeSH
- chemické techniky analytické * MeSH
- impedanční spektroskopie metody využití MeSH
- kofein * analýza farmakologie terapeutické užití MeSH
- lidé MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí metody využití MeSH
- polarografie metody využití MeSH
- spektrální analýza metody využití MeSH
- vysokoúčinná kapalinová chromatografie metody využití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
Optimum conditions were found for the determination of nanomolar and subnanomolar concentrations of genotoxic 2-aminofluoren-9-one (2-AFN) by adsorptive stripping differential pulse voltammetry (AdSDPV) at a hanging mercury drop minielectrode (HMDmE) after preliminary separation and preconcentration by solidphase extraction (SPE) in LiChrolut RP-18 E (500 mg) columns. The adsorbed analyte was eluted with acetone, the solution then evaporated to dryness, and the residue dissolved in acetate buffer (pH 4.0) (AcB). A sample was then measured by AdSDPV at the HMDmE, with the accumulation potential 100 mV (vs. Ag|AgCl in 1 mol l–1 KCl) and the accumulation time 120 s. Linear calibration curves were obtained for 2·10–11 – 1·10–9 mol l–1 2-AFN, with the limit of quantification (LQ) ≈ 4·10–11 mol l–1. The method was verified by the determination of 2-AFN in model samples of drinking and river water at concentrations 4·10–11 – 1·10–9 and 2·10–10 – 1·10–9 mol l–1 (LQ ≈ 6·10–11 and 4·10–10 mol l–1, respectively).
- MeSH
- chemické znečištění vody * MeSH
- elektrochemické techniky * metody přístrojové vybavení využití MeSH
- fluoreny analýza MeSH
- indikátory a reagencie * MeSH
- pitná voda MeSH
- polarografie * metody přístrojové vybavení využití MeSH
- polycyklické aromatické uhlovodíky * škodlivé účinky toxicita MeSH
- vodní hospodářství MeSH
- Publikační typ
- práce podpořená grantem MeSH
A new, rapid and very sensitive electrochemical method for the determination of a new pesticide clothianidin in tap and river water was developed. The electrochemical reduction and determination of clothianidin have been carried out at a hanging mercury drop electrode (HMDE) in various aqueous solutions in the pH range of 2–10 by cyclic voltammetry (CV) and cathodic stripping square wave voltammetry (SW CSV). The best results were obtained for the clothianidin determination by SW CSV method in 0.04 mol l–1 Britton Robinson buffer at pH 8.1. Various conditions of the procedure were checked. Elaborated electroanalytical procedure enable clothianidin determination in the concentration range of 2.0 × 10–8–9.9 × 10–7 mol l–1. The limit of detection (LOD) and limit of quantification (LOQ) were obtained as 2.00 × 10–9 and 2.36 × 10–8 mol l–1, respectively. Precision and accuracy of the developed method were checked by recovery studies in spiked tap and river water. The voltammetric determination has been validated using HPLC with UV detection.
A differential pulse polarographic (DPP) method has been developed for the determination of ascorbic acid (AA) and dehydroascorbic acid (DHA), the two main forms of Vitamin C. The method consists of the DPP analysis of a quinoxaline obtained by the derivatization of DHA with o-phenylenediamine. Results using the proposed method correlated well with those obtained by two reference methodologies: the common iodometric method and a published chromatographic methodology. It was also used in the study of Vitamin C degradation in fruit juices, showing that it involves an initial oxidation of AA to DHA, followed by hydrolytic degradation of the latter.
We have found that the determination of thiodiglycolic acid (TDGA) in urine may help to characterize metabolic imbalance of substances participating in methionine synthesis, which leads to hyperhomocystinuria. From the metabolic scheme, based on a proper combination of known facts, we attempted to theoretically explain and to demonstrate the possibilities of TDGA formation via different ways of homocysteine transformation. This scheme was used in evaluating the results obtained by testing urine of a woman suffering from impaired function of methionine synthase reductase (CblE type of homocystinuria). The amount of TDGA excreted in her morning urine was very sensitive to the changes in her treatment based upon a combination of N5-formyl tetrahydrofolate, betaine and vitamin B12. Vitamin B12 given in the evening either alone or together with betaine increased the TDGA excretion in the morning urine up to ten times. On the other hand, in the absence of vitamin B12, betaine in combination with N5-formyl tetrahydrofolate hindered the appearance of TDGA in the morning urine. Generally, the determination of TDGA in urine of an appropriately pretreated patient may indicate the degree of success of the treatment.
- MeSH
- betain metabolismus moč terapeutické užití MeSH
- financování vládou MeSH
- formyltetrahydrofoláty metabolismus moč terapeutické užití MeSH
- homocystein metabolismus moč MeSH
- lidé MeSH
- polarografie metody využití MeSH
- thioglykoláty izolace a purifikace moč MeSH
- vitamin B 12 metabolismus terapeutické užití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- srovnávací studie MeSH
- MeSH
- analýza moči MeSH
- glutathion * metabolismus MeSH
- kreatin * metabolismus MeSH
- kyseliny dikarboxylové * analýza metabolismus moč MeSH
- lidé MeSH
- metabolismus MeSH
- polarografie metody využití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- MeSH
- chemické techniky analytické metody normy MeSH
- elektrochemie metody trendy MeSH
- fyzikální chemie metody normy MeSH
- klinické laboratorní techniky využití MeSH
- organické látky chemie izolace a purifikace normy MeSH
- polarografie metody trendy využití MeSH
- vysokoúčinná kapalinová chromatografie využití MeSH
