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Magnetic micro solid-phase extraction for a novel UHPLC-DAD method for the determination of atomoxetine (ATX) in breast milk and human plasma
(Academia Română, 2024) Ceylan, Burhan; Kurnaz Yetim, Nurdan; Özcan, Cemile; Koç, Mümin Mehmet; Önal, Cem
Atomoxetine is a special pharmaceutics used for attention deficit hyperactivity disorder. It finds application in various age groups, including children, adolescents, and adults. Ultra high-performance liquid chromatographic technique (UHPLC) is an exceptional technique and provides swift, uncomplicated, and highly sensitive results. Such a technique has been formulated to analyse atomoxetine levels in both breast milk and human plasma. Magnetic micro solid phase extraction is simple, rapid, efficient, and precise method which was applied prior to chromatographic separation. In this method, magnetic adsorbents in the form of Fe3O4 magnetic nanoparticles were employed, and the adsorption process underwent optimization. Chromatographic separation was carried out using a reversed-phase C18 analytical column (5 μm × 4.6 mm × 150 mm) with a mobile phase composed of monobasic potassium dihydrogen orthophosphate (pH=6.8) and acetonitrile (50:50 v/v). The flow rate was set at 0.8 mL/min, and investigation was performed using DAD at 215±2 nm. The method's linearity was evaluated within the range of 0.5–20 μg/mL, achieving a correlation coefficient (r) of 0.999. Validation of the method encompassed accuracy, reproducibility, precision, robustness, specificity, quantification limits, and detection limits, adhering to EMA guidelines. The limit of detection (LOD) was found to be 0.03, while the limit of quantification (LOQ) was 0.11 μg/mL for both matrices. Interday and intraday relative standard deviation (RSD) values were determined to be below 2.5% for both assays. The suggested method is deemed to be a useful candidate for the conventional quantification of atomoxetine in human spiked breast milk and plasma.
Phenylsulfonylpiperazines as α-Glucosidase enzyme inhibitors: Design, synthesis, DFT calculations, docking and ADME studies
(Bitlis Eren Üniversitesi, 2024) Buran, Kerem; İnan, Yiğit; Akyüz, Gülşah Selin; Dervişoğlu Özdemir, Celile; Kocabaş, Fatih
Diabetes mellitus (DM) is one of the most common diseases affecting people all over the world. An important treatment for DM is the inhibition of the α-glucosidase enzyme. A wide range of biological activities of piperazine and sulfonamide moieties are known. In this study, five phenylsulfonyl piperazine derivatives were synthesized. Their inhibitory capacities were evaluated. The analogues (1-5) showed a good degree of inhibition of α-glucosidase enzyme. Compound 1 has the highest inhibition potential for the α-glucosidase enzyme. Its inhibition percentages (83.52±0.41) were higher than the reference molecule quercetin (81.41±0.02). In silico molecular docking studies were performed for the most potent compound 1 for α-glucosidase enzyme to determine possible protein-ligand interactions. Furthermore, a DFT study was carried out for the evaluation of the quantum mechanical and electronic properties. Finally, ADME profiles of the compounds were theoretically analyzed.
A simple UFLC method for the determination of Montelukast in human plasma
(ACG Publications, 2024) Önal, Cem; Kepekçi Tekkeli, Şerife Evrim; Önal, Armağan
In this investigation, an UFLC technique utilizing fluorimetric detection was reported for the analysis of Montelukast (MON) in plasma. The method involves pre-column derivatization using 4-bromomethyl-7- methoxycoumarin (BrMmC). The calibration curve linear concentrations from 10 to 1000 ng/mL. The method exhibited an average recovery rate of 95.49%. The newly developed method was effectively utilized to assess the pharmacokinetics of Montelukast (MON) following the administration of a single 10 mg tablet to a healthy male volunteer.
Spray-assisted drop formation liquid-phase microextraction for the determination of sertraline in environmental water samples with matrix-matching calibration in GC–MS
(SpringerOpen, 2024) Zeytinci, Nagehan Kübra; Akbıyık, Hilal; Tezgin, Emine; Zaman, Buse Tuğba; Dalgıç Bozyiğit, Gamze; Şaylan, Meltem; Bakırdere, Sezgin
Sertraline is used as an antidepressant drug for the treatment of psychiatric disorders, including anxiety and depres sion. In the current study, a simple and efective method was developed for the sensitive monitoring of sertraline in water samples using a GC–MS system. The spray-assisted droplet formation liquid-phase microextraction (SADF LPME) method was used as a sample preparation method for the enrichment of analytes. Accordingly, dichlo romethane was used as an extraction solvent and easily dispersed into a sample/standard solution using a lab-made modifed spray device without using a dispersing solvent. The signifcant factors afecting the SADF-LPME efciency, including sample pH, mixing conditions, extraction solvent type, and spray cycle, were univariately optimized to ascertain the extraction performance and applicability of the system. Under the optimized conditions, the plotted calibration curve of the method was linear in the range of 100.2–2011.7 µg/kg (mass-based standard preparation) with a good correlation coefcient (R2 ) of 0.9997. The detection and quantifcation limits of method were found to be 37.5 and 125 µg/kg, respectively. Validation of the method was successfully carried out using diferent tap water samples and applying a matrix-matching calibration strategy. The acceptable percent recoveries were recorded between 77.3 and 133.7%, with high repeatability. The recommended method is an alternative and fast extraction method with several advantages, including a simple experimental process, good dispersibility, and fast and superior extraction performance. It can be readily applicable to the monitoring and quantifcation of sertraline in tap water samples with good precision and accuracy.
Efficient removal of estrone and 17β‑estradiol from aqueous medium using UV irradiation‑assisted fenton process
(Springer Link, 2024) Dikmen, Yaren; Şaylan, Meltem; Oflu, Sude; Fırat Ayyıldız, Merve; Serbest, Hakan; Dalgıç Bozyiğit, Gamze; Bakırdere, Sezgin
The endocrine-disrupting compounds (EDCs) have high-risk implications for public health and the environment due to their potential to interfere with endocrine system functions. This study is based on an evaluation of the applying the UV-assisted Fenton process for the removal and degradation of 17β-estradiol and estrone in aqueous medium. The simple and affordable UV irradiation system was developed and applied to accelerate the Fenton reaction. High performance liquid chromatography (HPLC) was employed for the quantitative measurements of estrogenic hormones at 230 nm, which is highly sensitive and capable of accurately measuring hormones within 15 min. The LOD/LOQ values of HPLC system were recorded to be 0.03/0.11 mg/kg and 0.05 /0.15 mg/kg for estrone and 17β-estradiol, respectively. Fe3O4 magnetic nanoparticles and iron (II) sulfate solution were evaluated as appropriate iron sources under fixed UV irradiation to assess the Fenton process. The main parameters, namely hydrogen peroxide (H2O2) amount, iron (II) sulfate amount, pH, and UV irradiation period, were optimized univariately for determining the optimum conditions. The optimum conditions were recorded to be: 0.70 mL of pH 3.0 buffer solution, 1.25 mL of H2O2, 0.80 mL of 100 mg/L Fe2+ solution, and an irradiation time of 60 min. The removal experiments were also carried out on domestic wastewater to validate the system’s applicability. The percent removal efficiencies of both estrogenic hormones were calculated at higher than 99%. These results showed that high efficiency was achieved within the detection limits of the HPLC system. This proves the possibility of complete degradation of the analytes and their efficiency and practicality for pollution control and water quality improvement in future studies.
Development of an HPLC-UV method for the simultaneous determination of allantoin and D-panthenol in cosmetic products containing Aloe vera extracts
(Akadémiai Kiadó (AK), 2024) Ceylan, Burhan; Kepekçi Tekkeli, Şerife Evrim
A simple, fast and selective analytical method has been developed for the simultaneous determination of allantoin and D-panthenol in cosmetic products containing Aloe vera extracts. The proposed method depends on reversed-phase liquid chromatography with isocratic flow profile of the mobile phase composed of acetonitrile–10 mM phosphoric acid (pH 2.5) (85:15, v/v), with a C18 column at 30 8C. The analytes were detected with UV–vis. detector at 210 nm. The injection volume was 20 μL. The linearity ranges were found to be 0.2–20 and 0.1–10 μg mL 1 for allantoin and D-panthenol, respec tively. LOD values were found to be 0.07 μg mL 1 and 0.03 μg mL 1 , LOQ values were found to be 0.2 and 0.1 μg mL 1 for allantoin and D-panthenol, respectively. No interference was observed from concomitants. The developed method was applied to the analysis of 10 different type cosmetic products. It is foreseen that the method will be able to be used in order to carry out routine analysis, quality control and standardization in cosmetic products containing allantoin and D-panthenol.
CoSn(OH)6 nanocubes as a solid sorbent for the effective preconcentration of copper ions in cinnamon (Cinnamomum zeylanicum) extract
(Elsevier, 2024) Bahçıvan, Aleyna; Şaylan, Meltem; Sağdıç, Osman; Bakırdere, Sezgin
This study was aimed at developing a simple and efficient CoSn(OH)6 nanocubes-based preconcentration method for the preconcentration of copper ions from cinnamon extracts for determination by flame atomic absorption spectrometry. The cube-shaped sorbent was synthesized using the simple stoichiometric co-precipitation method under ambient conditions. Experimental factors of the method were evaluated with a comprehensive optimization approach to maximize the extraction efficiency for the analyte. Under the optimal conditions, the limit of detection (LOD), limit of quantitation (LOQ), and linear dynamic range were recorded as 0.98 µg/L, 3.28 µg/L, and 4.0-75 µg/L, respectively. The enhancement factor was calculated as 101.6-fold by comparing the LODs of the optimized and direct analysis systems. Percent recoveries were found to be within an acceptable range (77.6-115 %), with high repeatability using matrix matching calibration strategy. Results validated the proposed method as a highly efficient extraction approach for the monitoring of copper ions in herbal cinnamon extracts.
Synthesis of nanocube-shaped cobalt tin hydroxides for the preconcentration of lead in environmental seawater collected from antarctic region
(Wiley-VCH GmbH, 2024) Şaylan, Meltem; Fırat Ayyıldız, Merve; Zaman, Buse Tuğba; Polat Korkunç, Ümmügülsüm; Gürsoy, Selim; Çetin, Gülten; Bakırdere, Sezgin
Here, a simple/efficient analytical strategy based on dispersive solid phase extraction was developed using CoSn(OH)6 nanocubes for lead ions from environmental water samples by FAAS (flame atomic absorption spectrometry). CoSn(OH)6 was synthesized as an adsorbent using the co-precipitation method and characterized. The characterization studies proved the cube-shaped morphology and uniform size distribution. The optimal experimental conditions were found by optimization studies and, the limit of quantification (LOQ), limit of detection (LOD), linear dynamic range were recorded as 37.6 μg/L, 11.3 μg/L, and 40–600 μg/L, respectively. The enhancement factor of the presented method was calculated as 158.7-folds compared to the LOD of the conventional FAAS system. Recovery experiments were performed to check the method's applicability/accuracy and the percent recovery results varied from 89.0 % to 112.9 %. According to these findings, the developed method was successfully applied for the quantitative determination of the target analyte in a seawater sample matrix.
Pharmacokinetic analysis of febuxostat in human serum by UFLC based on fluorimetric derivatization
(Editions de l'Academie Republique Populaire, 2024) Binay, Emrullah; Önal, Cem; Önal, Armağan; Kepekçi Tekkeli, Şerife Evrim
An ultra fast liquid chromatographic (UFLC) method using fluorimetric detection for the quantitation of Febuxostat (FEB) in human serum was developed by precolumn derivatization with 4- bromomethyl-7-methoxy coumarin (BrMmC). The derivatization was catalyzed with dibenzo-18-crown-6-ether to produce a fluorescent derivative which was determined through fluorescence measurement with excitation at 320 nm and emission at 395 nm wavelengths. A C18 column with 100 cm  4.6 mm, 3 µm particule size was used for the UFLC separation procedure. A mixture of acetonitrile: methanol: 0.05 M aqueous ammonium acetate (pH 5.0) (40:40:20, v/v/v) was used as mobile phase. During the procedure, the flow rate was maintained at 0.5 mL/min. A calibration curve was then plotted as 0.005–3.0 µg/mL with a detection limit of 0.0022 µg/mL and quantification limit of 0.0073 µg/mL. The mean recovery to reveal the accuracy and relative standard deviation (RSD) that indicates the precision of the method were found out to be 85.20 % and less than 3.52 %, respectively. The utility of the new method has been demonstrated by measuring the pharmacokinetics of FEB by administration of 80 mg tablets to a healthy female volunteer, aged 42.
Implementation of simple and effective fine droplet formation-based spray-assisted liquid phase microextraction for the simultaneous determination of twenty-nine endocrine disruptor compounds and pesticides in rock, soil, water, moss, and feces samples from antarctica using gas chromatography-mass spectrometry
(Springer, 2024) Zaman, Buse Tuğba; Dalgıç Bozyiğit, Gamze; Şaylan, Meltem; Koçoğlu, Elif Seda; Kartoğlu, Bedrihan; Aydın, Efe Sinan; Girgin, Ayça; Borahan, Tülay; Oflu, Sude; Kılınç, Yağmur; Bakırdere, Emine Gülhan; Bakırdere, Sezgin
This study established the simultaneous determination of the selected endocrine-disrupting compounds (EDCs) and pesticides in rock, soil, water, moss, and feces samples collected from the Antarctic region. The spray-assisted droplet formation-based liquid phase microextraction (SADF-LPME) coupled to GC–MS system was developed and validated for the screening and monitoring of 29 selected EDCs and pesticides. Binary solvent system, 1:1 (v/v) dichlormethane: 1,2-dichloroethane mixture was employed as an extraction solvent and sprayed onto sample or standard solutions using a straightforward and practical spray apparatus. The factors afecting the extraction process such as extraction solvent type and ratio, extraction solvent volume (spray repetition), vortexing period, and sample pH were properly optimized. Analytical fgures of the merit of the method were recorded under the optimal extraction/chromatographic conditions. The LOD, LOQ, and enhancement factor were in the range of 1.0 to 6.6 ng/g, 3.2 to 22.1 ng/g, and 3.7 to 158.9, respectively. The method demonstrated a good linear working range for all the selected analytes with proper coefcients of determination. The usability and reliability of the microextraction strategy was confrmed using seawater, moss, and soil samples, and the %recoveries were within an acceptable range (>70%) for all examined samples. The environmental samples collected from the Horseshoe and Faure Islands of the Antarctica region were analyzed to assess the potential pollution of EDCs and pesticides. This method has the potential to be employed for the analysis of EDCs in routine analytical laboratories and for controlling and screening the organic pollutant content of diferent environmental samples.
Ultraviolet-assisted Fenton digestion of peach juice for the determination of nickel by flame atomic absorption spectrometry (FAAS)
(Taylor & Francis, 2023) Fırat Ayyıldız, Merve; Şaylan, Meltem; Yazıcı, Elif; Chormey, Doste Selali; Bakırdere, Sezgin
This study describes a simple and efficient UV–Fenton digestion of peach juice for nickel determination by flame atomic absorption spectrometry (FAAS). Herein, a hybrid of magnetic nanoparticles (MNPs) and hydrogen peroxide were used to digest the peach juice with UV irradiation. The effects of experimental parameters were systematically optimized to obtain the best digestion conditions. A laboratory-scale closed-box isolated reactor setup was designed for the digestion experiments in this study. A low relative standard deviation of 6.8% for the lowest calibration standard established the digestion method’s good precision for replicate samples. Several peach juice samples were utilized in spike recovery experiments to validate the method’s applicability and accuracy. The recoveries calculated for the samples spiked at four concentrations were satisfactory (92–106%), indicating that this simple and effective analytical approach can be utilized as an alternative to conventional microwave digestion.
A novel HPLC method for selexipag in human plasma and application to a prototype pharmacokinetic study
(Akademiai Kiado, 2023) Ceylan, Burhan; Tırıs, Gizem; Kepekçi Tekkeli, Şerife Evrim; Önal, Cem; Önal, Armağan
A novel simple and cost effective HPLC technique was presented for the quantification of selexipag (SLP) in human plasma sample and the technique’s applicability to a pharmacokinetic investigation. Chromatographic separation was achieved with C18 (5 μm 3 4.6 mm 3 150 mm) column, at 30 8C with isocratic elution, mobile phase composed of solution A (acetonitrile), and solution B (0.5% formic acid) (65:35 v/v) at flow rate 1.2 mL min 1 . The linearity range is 10–150 ng mL 1 . As sample preparation step human plasma was precipitated with acetonitrile and the detection was provided at 300 nm. The retention time is 8.20 ± 0.02 min. LOD is found to be 3.3 ng mL 1 for drug. The method was applied to the analysis of SLP in human plasma with good recovery as 97.83%. Validation of the studied methods was carried out according to EMA guideline. The new method applied on a prototype pharmacokinetic study by administration of 800 μg SLP to a healthy volunteer and parameters like AUC0–24, AUC0–∞, Cmax, tmax, and t1/2 were assessed.
T-cut slotted quartz tube-atom trap strategy for the on-line preconcentration of thallium in well water samples
(Elsevier, 2023) Bombom, Miray; Zaman, Buse Tuğba; Dalgıç Bozyiğit, Gamze; Şaylan, Meltem; Bayraktar, Ahsen; Arvas, Büşra; Yolaçan, Çiğdem; Bakırdere, Sezgin
In this study, an on-line preconcentration system was developed for the quantitative determination of thallium in well water samples using hydrogen-assisted T-cut slotted quartz tube atom trapping (HA-T-SQT-AT) coupled to flame atomic absorption spectrometry (FAAS). The method is based on trapping the thallium atoms on the inner surface of the T-SQT for a short period using sample aspiration and lean flame conditions. Then, hydrogen gas as a reducing agent was released instantly to free the trapped analyte atoms, resulting in a sharp and narrow signal. The system analytical performance was enhanced by performing comprehensive optimization of several factors. The linear range and LOD/LOQ values of the optimized method were found to be 7.5–––200 ng/mL and 2.6/8.7 ng/mL, respectively. Accuracy/practicability of the presented method were verified using well water samples, and the percent recoveries calculated using the external calibration approach were all above 80%.
A simple microwave-assisted synthesis of cobalt ferrite nanoparticles and its application for the determination of lead ions in rooibos (Aspalathus linearis) tea
(Elsevier, 2023) Fırat Ayyıldız, Merve; Karaman, Devrim Nur; Kartoğlu, Bedrihan; Şaylan, Meltem; Chormey, Dotse Selali; Bakırdere, Sezgin
In this study, a magnetic sorbent assisted dispersive solid phase extraction (DSPE) method was used to preconcentrate lead ions from rooibos tea samples for determination by slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS). Cobalt ferrite magnetic nanoparticles (CoFe2O4 MNPs) were synthesized by microwave assisted digestion. Limits of detection and quantification were calculated as 5.3 and 17.6 µg/L, respectively, in a linear dynamic range of 20–800 µg/L. The enhancement factor of the developed method was found to be 80- folds when compared to the detection limit of the regular FAAS system. The percent recoveries obtained for rooibos tea samples spiked at different concentrations were in the range of 77 – 125%, with high repeatability as indicated by low standard deviations. The findings of the study demonstrated that the CoFe2O4 MNPs-based extraction method is a straightforward, fast, affordable, safe, and eco-friendly approach to qualifying/quantifying lead with high precision in the selected beverage sample.
Determination of carnosic acid by a novel HPLC-UV method in human plasma and application to a prototype pharmacokinetic study
(Oxford Academic, 2024) Ceylan, Burhan; Tırıs, Gizem; Kepekçi Tekkeli, Şerife Evrim
An HPLC method with UV detection was developed for the determination of carnosic acid in human plasma and applied to a pharmacokinetic study after oral administration of Rosemary extract to a healthy volunteer. Sample preparation depends on liquid-liquid extraction with hexane. Chromatographic separation was achieved with C18 column (150 mm × 4.6 mm × 5 μm), at 25°C with isocratic elution, mobile phase composed of solution A (methanol), and solution B (2% o-phosphoric acid in water) (90:10, v/v) at flow rate of 1.0 mL/min. The analyte was detected at 230 nm. The retention time is 4.20 ± 0.03 min. The method was validated in terms of accuracy, precision, specificity, robustness and detection and quantification limits, in accordance with European Medicines Agency guidelines. LOD and LOQ were found to be 0.075 and 0.25 ng/mL, respectively. The method was applied to the analysis of carnosic acid in human plasma with good recovery as 91.7%. The plasma concentration-time profile and pharmacokinetic parameters: AUC0-t, AUC0-∞, Cmax, tmax, t1/2 were calculated according to the assays. The method can certainly be used for routine analysis of carnosic acid in human plasma after oral administration of Rosemary extract, and for phase I clinical studies and bioavailability-bioequivalance studies as well.
Analysis of capsaicinoids in chilli sauce with ultra fast liquid chromatography
(Bezmialem Vakıf Üniversitesi, 2022) Ceylan, Burhan; Önal, Cem; Önal, Armağan
Objective: In current study, quantification of the capsaicinoids in chilli sauces based on a sensitive ultra fast liquid chromatography method and derivatization with dansyl chloride (DNS-Cl) was described. Capsaicinoids are biosynthesized as secondary metabolites by chilli sauces. The major components of capsaicinoids are capsaicin (CPS) and dihydrocapsaicin (DCPS). Methods: Phenol groups within the CPS and DCPS are suitable for derivatization reaction using DNS-Cl (chemically named as 5-(dimethylamino) naphthalene-1-sulfonyl chloride) at pH 10 with 0.5 M sodium bicarbonate which leads formation of a derivative highly fluorescent properties that can be measured at 520 nm following excitation at 360 nm wavelength. Separation of the compounds was conducted on a chromatographic system having a mobile phase formed by a combination of acetic acid (0.5 M, pH 7.0 with NaOH) solution and acetonitrile under solvent programming on a consistent flow rate of 0.4 mL. min-1 using a C18 column. Results: Method validation was evaluated as per the regulations described in International Conference on Harmonization Guidelines. The calibration graph for CPS and DCPS was linear between 0.2 and 200 µg mL-1. Conclusion: The proposed analytical procedure represents a simple, time and cost effective method with a suitable selectivity regarding quantification of capsaicinoids in chilli sauces.
Determination of apigenin in cosmetics containing chamomile by high-performance liquid chromatography with ultraviolet detection (HPLC-UV)
(Taylor & Francis, 2023) Serim, Ecem; Ceylan, Burhan; Kepekçi Tekkeli, Şerife Evrim
A simple, rapid, and precise high performance liquid chromatography (HPLC) method was developed to determine the flavonoid apigenin in cosmetic products containing chamomile extracts. A C18 column was used as stationary phase and 70:30 ethanol:water was used as mobile phase with a 1 mL/min flow rate and isocratic elution. The temperature was stabilized at 25 degrees C during the separation. The injection volume was 50 mu L. The apigenin peak was eluted at 4.15 +/- 0.4 min. The method was validated according to International Conference on Harmonisation (ICH) criteria in terms of linearity, limit of detection, limit of quantitation, selectivity, sensitivity, robustness, accuracy, and precision. The limits of detection and quantitation were 0.060 and 0.2 mu g/mL respectively. The linear range was from 0.2 to 20 mu g/mL. The relative standard deviation values for intraday and interday analyses were less than 1.64%. The developed procedure was applied to the analysis of various cosmetic products. It is expected that the method is suitable for routine analysis, quality control and standardization of cosmetic products for apigenin.
Nickel hydroxide nanoflower-based dispersive solid-phase extraction of copper from water matrix
(Wiley, 2023) Şaylan, Meltem; Demirel, Rabia; Fırat Ayyıldız, Merve; Chormey, Doste Selali; Çetin, Gülten; Bakırdere, Sezgin
In this work, a dispersive solid-phase extraction method based on Ni(OH)2 nanoflowers (Ni(OH)2-NFs-DSPE) was developed to separate and preconcentrate copper ions from tap water samples for determination by flame atomic absorption spectrometry (FAAS). Ni(OH)2-NFs was synthesized using a homogeneous precipitation technique and used as sorbent for copper preconcentration. X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy were used to characterize the synthesized sorbent. All experimental variables were carefully optimized to achieve a high enhancement factor of 107.5-folds with respect to the detection sensitivity of the conventional FAAS. The proposed method's analytical parameters including LOD, LOQ, and linear range were determined as 1.33 μg/L, 4.42 μg/L, and 3.0-40 μg/L, respectively. To assess the applicability and reliability of the developed method, optimal conditions were applied to tap water samples and satisfactory percent recoveries (94-103%) were obtained for the samples spiked at 20 and 30 μg/L. This validated the accuracy and feasibility of the developed method to real samples. The developed method can be described as a simple, efficient, and rapid analytical approach for the accurate determination of trace copper ions in water samples.
Microwave assisted effective synthesis of CdS nanoparticles to determine the copper ions in artichoke leaves extract samples by flame atomic absorption spectrometry
(Academic Press Inc., 2023) Şaylan, Meltem; Metin, Berfin; Akbıyık, Hilal; Turak, Fatma; Çetin, Gülten; Bakırdere, Sezgin
In this study, an accurate and sensitive analytical strategy based on cadmium sulfide nanoparticles assisted dispersive solid phase extraction (CdS-NPs-DSPE) was developed for the preconcentration/separation of copper ions in the extract of artichoke leaves. The CdS-NPs-DSPE method was combined with slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS) for the first time. The CdS-NPs were synthesized using microwave-assisted reaction as a new and rapid synthesis method for the CdS precursor solution. The morphology and structure of the synthesized sorbent were characterized using SEM, XRD, and FT-IR. The optimum conditions of the method were as follows: 40 mL sample volume, 0.10 mL of pH 4.0 buffer solution, 7.5 mg CdS NPs, 30 s sonication period, and 100 µL of concentrated HNO3. According to the experimental results, the calibration plot was linear in the concentration range of 2.5–30 µg/L, with a detection limit of 0.71 µg/L. The enhancement in detection power was calculated as 162-folds based on LOD comparison. The reliability and applicability of the proposed method were validated by spiking artichoke leave extracts at different concentrations. The percent recoveries calculated for 50 and 150 µg/L piked samples were 87 ± 12.6 % and 116.8 ± 3.2 %, respectively. These findings verify that the proposed method can be used for accurate and precise determination of copper ions in artichoke leaves.
An UPLC method for the determination of sorafenib in human plasma by fluorimetric detection with pre-column derivatization and application to a pharmacokinetic study
(Editura Academiei Romane, 2022) Tırıs, Gizem; Kepekçi Tekkeli, Şerife Evrim; Önal, Cem; Ceylan, Burhan; Önal, Armağan
This research presents a new, sensitive and selective UPLC method with fluorometric detection for the determination of sorafenib in human plasma and application of the method to a pharmacokinetic study. Sorafenib was precolumn derivatized with 7-chloro-4-nitrobenzofurazan (NBD-Cl) and the separation of the fluorescent derivative was performed with a C18 column (50 mm x 2.1 mm, 1.7 µm) at 40ºC using a mobile phase composed of acetonitrile - 0.1% trifluoroacetic acid in water (60:40, v/v) by isocratic elution with flow rate of 0.5 mL min−1 . The injection volume was 7 µL. The method depends on the measurement of the derivative using fluorescence detection (λex = 398 nm, λem = 425 nm). The retention time of sorafenib was 3.10 ± 0.02 min. The novel method was validated in accordance with ICH criteria by studying on the parameters such as specificity, linearity, precision, accuracy and robustness. The method was determined to be linear in a concentration range of 0.25-10 µg mL−1 with the correlation coefficient of 0.9995. Limit of detection and quantitation were found to be 0.075 and 0.25 µg mL−1 , respectively. Intraday and interday RSD values were less than 5.48%. The plasma concentration–time profile and pharmacokinetic parameters such as AUC0–t , AUC0–∞, Cmax, tmax, t1/2 were measured according to the assays. The proposed method is feasible to investigate the bioequivalence and bioavailability and routine analysis of the drug in plasma.

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