جستجوی مقالات مرتبط با کلیدواژه « biological samples » در نشریات گروه « شیمی »

In this study, a dispersive magnetic solid phase extraction (DMSPE) was described by combining graphene oxide (GO) with Fe3O4 and CuO (Fe3O4@CuO&GO) for extraction and preconcentration of aspirin (ASP) in biological samples. The morphology and structure of the prepared nanocomposite was characterized and analyzed by XRD, SEM and FTIR techniques. Ion mobility spectrometry (IMS) method equipped to a corona discharge ionization source was exploited to determine ASA. The extraction parameters (desorption solvent, pH, adsorbent amount, extraction time and temperature) and also the operational parameters of IMS were investigated and optimized. Under the optimum conditions, the DMSPE–IMS method provided a linear range 6.0–40.0 ng for ASA with coefficient of determination R2 = 0.99. The LOD and LOQ values were 0.9 and 3.0 ng for ASA, respectively. The repeatability of developed method was evaluated as relative standard deviation (RSD% = 2.7). The proposed method was also used to determine ASA in human plasma and serum as biological samples, which recovery results were within 89.0–100.0%.

The current research examines the designation of an electrochemical sensor for the simultaneous measurement of morphine and methadone using graphene oxide /multi-walled carbon nanotube/zinc oxide nanorods/polypyrrolenanocomposite, coated on the surface of the graphite electrode reinforced by a hollow fiber.Its performance was investigated by voltammetry methods while the nanocomposite structure was confirmed by FTIR, EDX, XRD, and SEM techniques.To optimize the effectual factors, the Taguchi test designing method with L27(3x7) orthogonal array was applied. Thevoltammetricanalysisshowed that two irreversible oxidation peaks appeared at the potentials of 0.81 V and 0.41 V for methadone and morphine, respectively. Furthermore, the electrochemical investigations showed that the oxidation process of morphine and methadone wasunder the control of the diffusion phenomenon and two electrons and two protons had been exchanged on the surface of the electrode for bothanalytes. Chronoamperometry was used to measure the diffusion coefficients of drugs which were found for morphine and methadone to be 5.31×10-6 cm2s-1 and 1.19×10-6 cm2 s-1. Under optimal conditions, for morphine, two linear concentration ranges of 0.04-10 μM and 10.0-100 μM and a detection limit of 0.01 μM were noted whereas for methadone, two linear ranges were observed in 0.06-8.0 μM and 8.0-100 μM and the detection limit was 0.02 μM. The designed sensor can be well used for the simultaneous measurement of the drugs with relative recovery percentages in the range of 98.80-100.22%for morphine and in the range of 98.14-100.58% for methadone.

Clopidogrel with trade name plavix, is used effectively to reduce the incidence of ischaemic strokes, heart attacks and claudication. In this study, an ion mobility spectrometry (IMS) method was proposed for the clopidogrel determination in analytical and bio-analytical fields. Under experimental conditions, the analytical validation parameters of the proposed method were calculated and reported. The calibration graph was linear in range 30.0–2000.0 µg mL-1 for clopidogrel with two orders of magnitude and a goodness of fit, R > 0.99. The coefficient of variation (precision, n=10) was found to be within 7.5–8.6%, and also the concentration levels of 3.0 and 10.0 µg mL-1 from analyte were obtained for the limits of detection and quantification, respectively. The developed IMS method was successfully applied to determine clopidogrel with accurate recovery range (90.0–103.7%) in different matrices. The validation studies showed that the applied IMS was a simple, rapid, sensitive and reliable method for the clopidogrel analysis in the pharmaceutical and biological samples.