HPLC-methods in the clinical-chemical laboratory of the department of dermatology of the University of Bonn

Nissen, H. P.; Kreysel, H. W.

doi:10.1007/bf02290383

Cited by 7 publications

(3 citation statements)

References 159 publications

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“…Several methods have been described to determine netilmicin in pharmaceutical formulations and biological matrices. Precolumn derivatization LC with dansyl chloride 10, o ‐phthalaldehyde (OPA) 11–14, 1‐fluoro‐2,4‐dinitrobenzene 15, 16, 11‐fluorenylmethyl chloroformate 17, or OPA‐β‐mercaptopropionic acid 18, 19, and postcolumn LC derivatization with OPA 20, 21 combined with fluorescence or UV detection have been described. However, these techniques are time consuming and give problems in quantification.…”

Section: Introductionmentioning

confidence: 99%

Role of Water in the Chlorine Evolution Reaction at RuO₂‐Based Electrodes—Understanding Electrocatalysis as a Resonance Phenomenon

et al. 2012

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The reaction path of the Cl(2) evolution reaction (CER) was investigated by combining electrochemical and spectroscopic methods. It is shown that oxidation and reconstruction of the catalyst surface during CER is a consequence of the interaction between RuO(2) and water. The state of the RuO(2) surface during the electrochemical reaction was analyzed in situ by using Raman spectroscopy to monitor vibrations of the crystal lattice of RuO(2) and changes in the surface concentration of the adsorbed species as a function of the electrode potential. The role of the solvent was recognized as being crucial in the formation of an oxygen-containing hydrophilic layer, which is a key prerequisite for electrocatalytic Cl(2) formation. Water (more precisely the OH adlayer) is understood not just as a medium that allows adsorption of intermediates, but also as an integral part of the intermediate formed during the electrochemical reaction. New insights into the general understanding of electrocatalysis were obtained by utilizing the vibration frequencies of the crystal lattice as a dynamic catalytic descriptor instead of thermodynamic descriptors, such as the adsorption energy of intermediates. Interpretation of the derived "volcano" curve suggests that electrocatalysis is governed by a resonance phenomenon.

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Section: Introductionmentioning

confidence: 99%

Role of Water in the Chlorine Evolution Reaction at RuO₂‐Based Electrodes—Understanding Electrocatalysis as a Resonance Phenomenon

et al. 2012

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“…Several methods have been described to determine netilmicin in pharmaceutical formulations and biological matrices. Precolumn derivatization LC with dansyl chloride [10], o-phthalaldehyde (OPA) [11][12][13][14], 1-fluoro-2,4-dinitrobenzene [15,16], 11-fluorenylmethyl chloroformate [17], or OPA-b-mercaptopropionic acid [18,19], and postcolumn LC derivatization with OPA [20,21] combined with fluorescence or UV detection have been described. However, these techniques are time consuming and give problems in quantification.…”

Section: Introductionmentioning

confidence: 99%

Development and validation of an improved reversed‐phase liquid chromatographic method combined with pulsed electrochemical detection for the analysis of netilmicin

Manyanga

Hoogmartens

Adams

2010

J of Separation Science

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Netilmicin is one of the aminoglycoside antibiotics that lacks a strong UV absorbing chromophore. However, the application of pulsed electrochemical detection has been used successfully for the direct analysis of aminoglycoside antibiotics. This study describes an improved LC method combined with pulsed electrochemical detection for the analysis of netilmicin. Using a Zorbax SB C-18 column (250 mm x 4.6 mm id, 5 microm), isocratic elution was carried out with a mobile phase containing sodium sulfate (20 g/L), sodium octanesulfonate (0.3 g/L), THF (20 mL/L), and 0.2 M phosphate buffer pH 3.0 (50.0 mL/L). The robustness of the method was examined by means of an experimental design. The method proved to be sensitive, repeatable, linear, and robust. The method has also been used to analyze some commercial netilmicin samples.

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“…However, the sensitivity is rather low and some impurities like 1‐ N ‐ethylgaramine, which lacks the double bond, cannot be detected. Reversed‐phase liquid chromatography (LC) combined with pre‐column derivatization with dansyl chloride,9 o ‐phthalaldehyde (OPA),10–12 1‐fluoro‐2,4‐dinitrobenzene13, 14 or OPA‐ β ‐mercaptopropionic acid15, 16 and post‐column derivatization with OPA17, 18 combined with fluorescence or UV detection have been described for the determination of netilmicin in various matrices. Adams and co‐workers first reported a non‐derivative LC method using a pulsed electrochemical detector (PED) to analyze netilmicin sulphate as a drug substance and to determine its impurities 19.…”

mentioning

confidence: 99%

Characterization of impurities in sisomicin and netilmicin by liquid chromatography/mass spectrometry

Schepdael

Hoogmartens

et al. 2008

Rapid Comm Mass Spectrometry

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The characterization of unknown impurities present in netilmicin and sisomicin by liquid chromatography (LC) coupled with mass spectrometry (MS) is described. The volatile ion-pairing agent trifluoroacetic acid (TFA) was used for the retention of the main compounds and their impurities on a reversed-phase (RP) C18 column, because they are highly hydrophilic and basic compounds. The method showed good separation between netilmicin and its four potential related substances prescribed in the European Pharmacopoeia, which were identified by comparison of their retention times with those of the reference substances. Furthermore, in total 16 unknown impurities in a netilmicin sample and six in a sisomicin sample with unknown identity were detected. The structures of the unknown compounds were deduced based on comparison of fragmentation patterns with those of the reference substances investigated in LC/MSn experiments by the use of electrospray ion trap mass spectrometry.

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HPLC-methods in the clinical-chemical laboratory of the department of dermatology of the University of Bonn

Cited by 7 publications

References 159 publications

Role of Water in the Chlorine Evolution Reaction at RuO₂‐Based Electrodes—Understanding Electrocatalysis as a Resonance Phenomenon

Role of Water in the Chlorine Evolution Reaction at RuO₂‐Based Electrodes—Understanding Electrocatalysis as a Resonance Phenomenon

Development and validation of an improved reversed‐phase liquid chromatographic method combined with pulsed electrochemical detection for the analysis of netilmicin

Characterization of impurities in sisomicin and netilmicin by liquid chromatography/mass spectrometry

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HPLC-methods in the clinical-chemical laboratory of the department of dermatology of the University of Bonn

Cited by 7 publications

References 159 publications

Role of Water in the Chlorine Evolution Reaction at RuO2‐Based Electrodes—Understanding Electrocatalysis as a Resonance Phenomenon

Role of Water in the Chlorine Evolution Reaction at RuO2‐Based Electrodes—Understanding Electrocatalysis as a Resonance Phenomenon

Development and validation of an improved reversed‐phase liquid chromatographic method combined with pulsed electrochemical detection for the analysis of netilmicin

Characterization of impurities in sisomicin and netilmicin by liquid chromatography/mass spectrometry

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Product

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Role of Water in the Chlorine Evolution Reaction at RuO₂‐Based Electrodes—Understanding Electrocatalysis as a Resonance Phenomenon

Role of Water in the Chlorine Evolution Reaction at RuO₂‐Based Electrodes—Understanding Electrocatalysis as a Resonance Phenomenon