Analytical chemistry

DERIVATIZATION TECHNIQUES BASED ON CHARGE TRANSFER REACTIONS FOR SPECTROPHOTOMETRIC DETERMINATION OF JOSAMYCIN IN VARIOUS DOSAGE FORMS

Author(s):

Abdelghani Mahmoudi and Ann Van Schepdael

Field: Analytical chemistry
Type: Research paper
Issue: 2024 Volume 19, no.1
Pages: 37-46

Keywords: spectrophotometric analysis, josamycin, 1,4-naphthoquinone-4-sulphonate, menadione.
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https://doi.org/10.19261/cjm.2024.1165

Abstract (PDF)
Graphical Abstract: The developed spectrophotometric methods were based on charge transfer reactions of naphthoquinones with Josamycin. Methods validity was tested and the results were in accordance with ICH guidelines. Procedures showed successful adaptability for an easy analysis of this macrolide in various dosage forms and can be used for quality control purposes.

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ANTIOXIDANT CO-ACTIONS OF ASCORBIC AND DIHYDROXYFUMARIC ACIDS INVESTIGATED BY EPR SPECTROSCOPY

Author(s):

Crina Vicol, Alexandra Sârghi, Adrian Fifere, Gheorghe Duca

Field: Analytical chemistry
Type: Research paper
Issue: 2024 Volume 19, no.1
Pages: 29-36

Keywords: dihydroxyfumaric acid, ascorbic acid, EPR spectroscopy, synergy, antioxidant.
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https://doi.org/10.19261/cjm.2024.1190

Abstract (PDF)
Graphical Abstract: The study presents data on the antioxidant interaction between ascorbic and dihydroxyfumaric acids determined via DPPH method, by applying EPR spectroscopy. The type of antioxidant interaction is dependent on the concentration ratio of the ascorbic and dihydroxyfumaric acids, thus, at the mM DHF/mM AA ratios of 1.4 and 1.7 the highest synergistic effects of 1.24 have been noticed, but at the mM DHF/mM AA ratio of 1 – an antagonistic effect of 0.93 was registered.

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SIMULTANEOUS QUANTITATIVE ESTIMATION OF LISINOPRIL AND HYDROCHLOROTHIAZIDE RESIDUES USING HPLC FOR CLEANING VALIDATION

Author(s):

Imeda Rubashvili, Natela Karukhnishvili, Khatuna Makharadze

Field: Analytical chemistry
Type: Research paper
Issue: 2020 Volume 15, no.1
Pages: 8-21

Keywords: lisinopril, hydrochlorthiazide, swab sampling, rinse sampling, HPLC, validation.
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DOI: http://dx.doi.org/10.19261/cjm.2020.669

Abstract (PDF)
Graphical Abstract: A new, rapid and selective, HPLC method for simultaneous quantitative estimation of lisinopril and hydrochlorothiazide residues and sampling procedures from pharmaceutical manufacturing equipment surfaces were developed and validated. The sampling procedures have a good recovery (>80%). The limit of quantitation of the HPLC method - 0.155 µg/mL and 0.025 µg/mL for lisinopril and hydrochlorothiazide, respectively.

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DEVELOPMENT AND VALIDATION OF AN ASSAY METHOD FOR CIPROFLOXACIN HYDROCHLORIDE DETERMINATION IN COMBINATION EAR DROPS

Author(s):

Livia Uncu, Elena Donici, Vladimir Valica, Oxana Vîslouh, Veaceslav Gonciar, Sergiu Parii

Field: Analytical chemistry
Type: Research paper
Issue: 2019 Volume 14, no.2
Pages: 56-61

Keywords: ciprofloxacin hydrochloride, UV-Vis spectroscopy, validation, ear drop, Ocimum basilicum.
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DOI: http://dx.doi.org/10.19261/cjm.2019.607

Abstract (PDF)
Graphical Abstract: A simple, precise and accurate UV-Vis spectrophotometric method has been developed and validated for the estimation of ciprofloxacin hydrochloride from combination ear drops with basil oil (Ocimum basilicum). The results of the validation of the method demonstrate that the developed method is simple, rapid, accurate and robust over the concentration range 2-10 μg/mL of ciprofloxacin hydrochloride in combination with volatile basil oil.

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STRUCTURAL ASPECTS OF LACTOFERRIN AND SERUM TRANSFERRIN OBSERVED BY FTIR SPECTROSCOPY

Author(s):

Gheorghe Duca, Lilia Anghel, Raul Victor Erhan

Field: Analytical chemistry
Type: Short communication
Issue: 2018 Volume 13, no.1
Pages: 111-116

Keywords: human lactoferrin, human serum transferrin, FTIR spectroscopy, amino acid, secondary structure.
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DOI: http://dx.doi.org/10.19261/cjm.2018.482

Abstract (PDF)

Graphical Abstract: In this work, Fourier transform infrared spectroscopy was used to highlight the structural differences between the human lactoferrin and human serum transferrin. The results clearly show the structural differences of human lactoferrin and human serum transferrin. The second derivative analysis of the FTIR spectra allows the direct identification of secondary structure components of the human lactoferrin and human serum transferrin.

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BUFFER CAPACITY IN HETEROGENEOUS MULTICOMPONENT SYSTEMS. REVIEW

Author(s):

Oxana Spinu, Igor Povar

Field: Analytical chemistry
Type: Review
Issue: 2015 Volume 10, no.2
Pages: 8-25

Keywords: buffer action, complex formation, thermodynamic stability, extraction multicomponent system, heterogeneous equilibria.
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Abstract (PDF)

DOI: dx.doi.org/10.19261/cjm.2015.10(2).01

Graphical Abstract: The quantitative basis of the theory of buffer properties for two-phase acid-base buffer systems and for multicomponent heterogeneous systems has been derived. The analytical equations with respect to all components for diverse multicomponent systems were deduced. It has been established, that the buffer capacities of components are mutually proportional.

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METHOD OF INFRARED SPECTRA REGISTRATION OF ACTIVATED CARBONS IN POTASSIUM BROMIDE PELLETS

Author(s):

Diana Shepel, Tatiana Goreacioc, Tudor Lupascu, Mihail Filippov, Maria Rusu

Field: Analytical chemistry
Type: Short communication
Issue: 2015 Volume 10, no.1
Pages: 113-115

Keywords: infrared spectroscopy, activated carbons, potassium bromide KBr pellets.
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Abstract (PDF)

DOI: dx.doi.org/10.19261/cjm.2015.10(1).16

Graphical Abstract: This communication is devoted to the elaboration of a new optimal technique of infrared spectra registration of activated carbons in potassium bromide pellets. Authors investigated the dependence of the intensity of the least overlapping infrared bands of activated carbons on the conditions of preparation, recording of the spectrum, and the degree of homogenization with potassium bromide.

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METHOD FOR NITRATE DETERMINATION IN WATER IN THE PRESENCE OF NITRITE

Author(s):

Maria Sandu, Tudor Lupascu, Anatol Tarita, Tatiana Goreacioc, Sergiu Turcan, Elena Mosanu

Field: Analytical chemistry
Type: Research paper
Issue: 2014 Volume 9, no.2
Pages: 8-13

Keywords: water, nitrate determination, nitrites, sulfaminic acid, Griess reagent, reducing mixture
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Abstract (PDF)

DOI: dx.doi.org/10.19261/cjm.2014.09(2).01

Graphical Abstract: The study relates to determination of nitrate in presence of nitrite in water and can be used in the quality monitoring of natural water (surface and groundwater), drinking water, water from fish farms and public aquaria where autonomous filters is used. The nature and quantity of reagents used have insignificant impact on natural waters and sewages. According to the investigation, the method includes the removal of nitrite from the solution/water with sulfaminic acid, the nitrate ion reduction to nitrite using a reducing mixture that contains Na₂SO₄ and zinc dust in ratio of 100:5 and determining the nitrite with the Griess reagent.

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STUDY OF SOME ARCHAEOMETRIC CHARACTERISTICS USED IN PANEL PAINTING ICONS AUTHENTICATION

Author(s):

Raluca Anamaria Cristache, Ana Maria Budu, Petronela Spiridon, Viorica Vasilache, Ion Sandu

Field: Analytical chemistry
Type: Research paper
Issue: 2014 Volume 9, no.2
Pages: 14-18

Keywords: icon, historic paper, SEM-EDX, micro-FTIR
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Abstract (PDF)

DOI: dx.doi.org/10.19261/cjm.2014.09(2).02

Graphical Abstract: The authentication of cultural heritage assets is a complex process of scientific investigation which regards obtaining information about: author (painter), the period when it was made, the owners and other data related to the main contexts of their evolution in time (routes travelled). This work presents a comparative study of the paper used in the preparation layer of three icons painted in Russian style. As an analysis techniques were used the micro and macro photography assisted by Optical Microscopy (OM), SEM-EDX and micro-FTIR.

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CATALYTIC WAVE OF CHLORATE IONS IN THE PREZENCE OF THE MOLYBDENUM (VI) - 2,3-DIHYDROXYBENZALDEHYDE COMPLEX

Author(s):

Ludmila Kiriyak, Tatiana Cazac, M. Revenco, and I. Povar

Field: Analytical chemistry
Type: Research paper
Issue: 2010 Volume 5, no.2
Pages: 24-29

Keywords: Voltammetry, catalytic current, molybdenum, 2,3-dihydroxybenzaldehyde, potassium chlorate.
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Abstract (JPEG)

DOI: dx.doi.org/10.19261/cjm.2010.05(2).02

Graphical Abstract: The polarographic catalytic current in acid solutions of Mo(VI),

2,3-dihydroxybenzaldehyde (2,3-DHBA) and chlorate ions has been investigated. The scheme of reactions taking place in the solutions and on the electrode has been elaborated. The increase of the catalytic current is explained by the formation of the active intermediate complex [Mo(V)×2,3-DHBA (ClO₃^-)]. The rate constant of formation for the active intermediate complex K = 2.5 × 10⁶ mol^-1 × dm³ × s^-1, the activation energy of reaction E_a=14.0 kcal×mol^-1 and the activation entropy ∆S_a^¹= -28.3 e.u. have also been determined.

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