scholarly journals Fiberoptic-Coupled Spectrofluorometer with Array Detection as a Process Analytical Chemistry Tool for Continuous Flow Monitoring of Fluoroquinolone Antibiotics

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Nader Shokoufi ◽  
Maryam Vosough ◽  
Mona Rahimzadegan-Asl ◽  
Atefeh Abbasi-Ahd ◽  
Mahsa Khatibeghdami

Nowadays, there is an increasing need for sensitive real-time measurements of various analytes and monitoring of industrial products and environmental processes. Herein, we describe a fluorescence spectrometer in continuous flow mode in which the sample is fed to the flow cell using a peristaltic pump. The excitation beam is introduced to the sample chamber by an optical fiber. The fluorescence emitted upon excitation is collected at the right angle using another optical fiber and then transmitted to the fluorescence spectrometer which utilizes an array detector. The array detection, as a key factor in process analytical chemistry, made the fluorescence spectrometer suited for multiwavelength detection of the fluorescence spectrum of the analytes. After optimization of the experimental parameters, the system has been successfully employed for sensitive determination of four fluoroquinolone antibiotics such as ciprofloxacin, ofloxacin, levofloxacin, and moxifloxacin. The linear dynamic ranges of four fluoroquinolones were between 0.25 and 20 μg·mL−1, and the detection limit of the method for ciprofloxacin, ofloxacin, levofloxacin, and moxifloxacin were 81, 36, 35, and 93 ng·mL−1, respectively. Finally, the proposed system is carried out for determination of fluoroquinolones in some pharmaceutical formulations.

2010 ◽  
Vol 93 (6) ◽  
pp. 1748-1756 ◽  
Author(s):  
Tomasz Tuzimski

Abstract The application of TLC with a diode array detector (TLC-DAD) and HPLC-DAD after SPE for identification and quantitative analysis of pesticides in water samples is demonstrated. The procedures described for the determination of compounds are inexpensive and can be applied to routine analysis of analytes in water samples after preliminary cleanup and concentration by SPE. Average recoveries for four different cartridges and three solvents by the proposed HPLC-DAD method after SPE also are presented. The efficiency of the SPE procedure was evaluated using real water samples from the Zemborzycki Reservoir, near Lublin, southeastern Poland. The method was validated for precision, repeatability, and accuracy.


2016 ◽  
Vol 99 (5) ◽  
pp. 1223-1232 ◽  
Author(s):  
Hee-Jung Sim ◽  
Byungjoo Kim ◽  
Joonhee Lee

Abstract This paper describes a practical approach using an LC diode-array detector (DAD) and MS for the quantitation of B-group vitamins (thiamine, riboflavin, nicotinamide, pantothenic acid, pyridoxine, biotin, folic acid, and cyanocobalamin) in multivitamin supplements. The purpose of this study was to optimize the extraction and chromatographic conditions without application of internal standards to determine B-group vitamins in multivitamins. Chromatographic separation on a C18 column was optimized on the basis of chromatographic behavior depending on pH variation of the mobile phase. The optimized methods showed good r values, with RSD values lower than 2.44 and 3.09% for most of the B-group vitamins (except cyanocobalamin) using LC–DAD and LC-MS, respectively. The methods were also proved to be reproducible, with RSD values of 0.96 and 2.48% being obtained with LC–DAD and LC-MS, respectively. In addition, the developed analytical methods for B-group vitamins were validated using certified reference materials and were applied to commercially available multivitamin tablets.


2021 ◽  
Author(s):  
Ewelina Patyra ◽  
Krzysztof Kwiatek

AbstractFour antibiotics, oxytetracycline, tetracycline, doxycycline, and chlortetracycline were separated and quantified in medicated feed. Tetracyclines from feed samples were extracted with 0.01 M citric buffer and acetonitrile (pH 3.0) and further purified with 0.45 µm syringe filters. The purified extract was separated on commercial RP-C18 column and analyzing using liquid chromatograph (LC) with two different detectors: diode array detector (DAD) and mass spectrometry (MS). These methods provided average recoveries from 72.2 to 101.8% for high pressure liquid chromatography (HPLC) with diode array detection and from 45.6 to 87.0% for liquid chromatography with mass spectrometry. The limit of detection in medicated feed ranged from 4.2 to 10.7 mg kg−1 for HPLC–DAD and 5.6 to 10.8 mg kg−1 for LC–MS. Our experiment showed that using the same extraction mixture we do not obtain the same recovery values for the analyzed compounds using two different detection techniques such as DAD and MS.


2011 ◽  
Vol 65 (4) ◽  
Author(s):  
Katarína Maráková ◽  
Peter Mikuš ◽  
Juraj Piešťanský ◽  
Emil Havránek

AbstractThe present work illustrates the potential of the capillary zone electrophoresis (CZE) separation technique coupled with the on-capillary diode array detector (DAD) for highly reliable determination of curcuminoids (curcumin, CUR, demethoxycurcumin, DCUR, and bisdemethoxycurcumin, BCUR) in substances (commercially available plant extract) and pharmaceutical preparation (commercial pharmaceutical capsules) with minimal sample preparation; (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD) was chosen for an anionic separation of CUR and its structural analogues (DCUR and BCUR) as an appropriate complexing agent (i) providing complete resolution of the curcuminoids and (ii) reducing adsorption of these hydrophobic analytes onto the capillary wall. DAD detection was utilised for characterisation of the composition of the separated zones via differences in the corresponding UV-VIS spectra (scanned at interval of 200–800 nm). Reference and real spectra of the analytes demonstrated that the proposed separation method was sufficiently selective to produce well-separated (i.e. spectrally homogeneous) analyte zones with no interfering compounds present. Successful validation and application of the CZE-DAD method proposed here suggest its routine use in highly effective and reliable analysis of curcuminoids in pharmaceutical samples.


Author(s):  
B.A. Lapshinov ◽  
◽  
N.I. Timchenko ◽  

Spectral pyrometry was used to determine the surface temperature distribution of Si, Nb, Cu, and graphite samples when they were locally heated by continuous radiation of an Nd:YAG laser (λ = 1.064 μm). With prolonged exposure to radiation, a stationary temperature field was established in the samples. The thermal spectra were recorded with a small spectrometer in the visible range in the temperature range above 850 K. The optical fiber used to transmit the radiation spectrum to the spectrometer had an additional diaphragm with a diameter of 1 mm located at a certain distance from the fiber end, which ensured the locality of the recorded spectra. The optical fiber moved continuously along the sample, and the spectrometer recorded up to 100 spectra with a frequency of 5-10 Hz. The temperature profile of the samples was calculated based on the results of processing the spectra using the Spectral Pyrometry program.


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