Determination of cadmium in urine by platform ET-AAS independent of matrix composition

1992 ◽  
Vol 343 (3) ◽  
pp. 319-323 ◽  
Author(s):  
R. Fraile ◽  
Z. A. de Benzo ◽  
M. Velosa
Keyword(s):  
Matrix Composition ◽  
Cadmium In Urine

scholarly journals Steps in Mechanotransduction Pathways that Control Cell Morphology

2019 ◽  
Vol 81 (1) ◽  
pp. 585-605 ◽  
Author(s):  
Haguy Wolfenson ◽  
Bo Yang ◽  
Michael P. Sheetz
Keyword(s):  
Tyrosine Kinases ◽  
Receptor Tyrosine Kinases ◽  
Control Cell ◽  
Matrix Composition ◽  
Cell Behavior ◽  
Repeated Testing ◽  
Cellular Functions ◽  
Rigidity Sensing ◽  
Controlled Environments

It is increasingly clear that mechanotransduction pathways play important roles in regulating fundamental cellular functions. Of the basic mechanical functions, the determination of cellular morphology is critical. Cells typically use many mechanosensitive steps and different cell states to achieve a polarized shape through repeated testing of the microenvironment. Indeed, morphology is determined by the microenvironment through periodic activation of motility, mechanotesting, and mechanoresponse functions by hormones, internal clocks, and receptor tyrosine kinases. Patterned substrates and controlled environments with defined rigidities limit the range of cell behavior and influence cell state decisions and are thus very useful for studying these steps. The recently defined rigidity sensing process provides a good example of how cells repeatedly test their microenvironment and is also linked to cancer. In general, aberrant extracellular matrix mechanosensing is associated with numerous conditions, including cardiovascular disease, aging, and fibrosis, that correlate with changes in tissue morphology and matrix composition. Hence, detailed descriptions of the steps involved in sensing and responding to the microenvironment are needed to better understand both the mechanisms of tissue homeostasis and the pathomechanisms of human disease.

scholarly journals Nanomaterial-Based Carbon Paste Electrodes for Voltammetric Determination of Naproxen in Presence of Its Degradation Products

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Hassan A. M. Hendawy ◽  
Waheed M. Salem ◽  
Mahmmoud S. Abd-Elmonem ◽  
Elmorsy Khaled
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanomaterials ◽  
Degradation Products ◽  
Phosphate Buffer Solution ◽  
Pharmaceutical Preparations ◽  
Matrix Composition ◽  
Human Blood Plasma ◽  
Carbon Paste ◽  
Carbon Paste Electrodes

The present work describes a novel, simple, and fast electroanalytical methodology for naproxen (NAP) determination in pharmaceutical formulations and biological fluids in the presence of its degradation products. Carbon paste electrodes (CPEs) modified with different carbon nanomaterials, namely, glassy carbon powder (GCE), multiwall carbon nanotubes (MWCNTs), single-walled carbon nanotubes (SWCNTs), graphene nanosheets (Gr), and graphene oxides (GO) were tested. Comprehensive studies were performed on the electrode matrix composition including the nature of the pasting liquids, pH, carbon nanomaterials, and mode of electrode modification. Two anodic oxidation peaks were recorded at 0.890 and 1.18 V in 1 × 10−1 mol·L−1 phosphate buffer solution at pH 6. Oxidation of naproxen (NAP) is an irreversible diffusion-controlled process. Calibration plots were rectilinear in the concentration ranging from 0.067 to 1.0 µg·mL−1 with correlation coefficient 0.9979. Photodegradation of NAP resulted in disappearance of the oxidation peak at 1.18 V, allowing simultaneous determination of NAP in presence of its degradation product. The achieved high sensitivity and selectivity suggest the application of the proposed protocol for naproxen determination in pharmaceutical preparations and human blood plasma.

scholarly journals Extraction-chromatographic determination of narcotic drugs and psychotropic substances in objects of complex matrix composition

2021 ◽  
Vol 65 (4) ◽  
pp. 422-430
Author(s):  
O. N. Mikhniuk ◽  
S. M. Leshchev
Keyword(s):  
Aqueous Solutions ◽  
Sharp Decrease ◽  
Chromatographic Determination ◽  
Matrix Composition ◽  
Gas Chromatography Mass Spectrometry ◽  
Maximum Efficiency ◽  
Psychotropic Substances ◽  
Matrix Components ◽  
Narcotic Drugs

A comparison of the capabilities of two methods for extraction-chromatographic determination of narcotic drugs and psychotropic substances in various objects (syrups, ointments, tablets, herbal mixtures, etc.), the screening methanol method commonly used in the practice of customs and forensic examination and the proposed extraction method based on the use of water phase (in particular, water solutions of salts) for preliminary effective separation of analytes from matrix components was made. In extraction systems of hexane–water, hexane–aqueous solutions of inorganic salts (sodium chloride, dipotassium phosphate and potassium carbonate), chloroform–water, the method of gas chromatography – mass spectrometry was used to determine the distribution constants (P) of organic bases – narcotic drugs and psychotropic substances (N-methylephedrine, methamphetamine, amphetamine, methadone, dihydrocodeine, hydrocodone, oxycodone, ketamine, cocaine zolpidem, fentanyl, harmine, harmaline). Based on the obtained extraction characteristics of analytes and matrix components, the optimal extractants and extraction conditions, which ensure the maximum efficiency of separation of analytes and matrix components, as well as the concentration of the analyte were substantiated. The use of extraction using water and aqueous solutions of salts provides both a sharp decrease in the detection limit (from 10–3 to 10–7 mol/dm3) in comparison with the methanol method and stable working of chromatographic equipment due to the removal of thermally unstable matrix components was shown.

A Polarographic Method for the Simultaneous Determination of Lead and Cadmium in Urine

AIHAJ ◽  
1967 ◽  
Vol 28 (6) ◽  
pp. 595-598 ◽  
Author(s):  
O. E. Knockaert ◽  
G. L. Maes ◽  
M. H. Faes
Keyword(s):  
Simultaneous Determination ◽  
Polarographic Method ◽  
Cadmium In Urine ◽  
Lead And Cadmium
Sign in / Sign up

Export Citation Format

Share Document