A Simple and Rapid HPLC Method for the Direct Determination of Residual Monomers Released From Dental Polymeric Materials in Blood Serum and Urine

In this paper the use of cholesterol oxidase derivatized with a fluorescein derivative is proposed for the direct determination of total cholesterol in blood serum. The method is based on the changes in the fluorescence of the solution during the enzymatic reaction (λexe = 498 nm and λem 519 nm). A mathematical model which relates the analytical signal to the total cholesterol concentration was developed, and the model can also be used to obtain some of the thermodynamic constants of the process. The method has a linear response range up to 70 mg/L of cholesterol, a detection limit of 2.5 mg/L, and the precision was 1.0% (40 mg/L cholesterol, n = 10). The method was applied to total cholesterol determination in blood serum samples. The results were compared to those obtained by a commercial analyzer, and statistically similar results were obtained. The use of derivatized cholesterol oxidase makes it possible to simplify the methodology normally used in this type of determination (the indicator reaction is avoided and the number of reagents reduced), with the added advantage that the analytical signal is independent of the concentrations of O2 and cholesterol oxidase.

Download Full-text

Determination of 14 trace elements in blood, serum and urine after environmental disaster in the Doce River basin: Relationship between mining waste and metal concentration in the population

Journal of Trace Elements in Medicine and Biology ◽

10.1016/j.jtemb.2021.126920 ◽

2021 ◽

pp. 126920

Author(s):

Alice Rodrigues de Matos ◽

Márcia Cristina da Silva Faria ◽

Bruna Moreira Freire ◽

Rodrigo Mendes Pereira ◽

Bruno Lemos Batista ◽

...

Keyword(s):

Trace Elements ◽

Blood Serum ◽

Metal Concentration ◽

River Basin ◽

Mining Waste ◽

Environmental Disaster ◽

Doce River ◽

Serum And Urine

Download Full-text

Membrane Sensors for the Selective Determination of Donepezil Hydrochloride

Journal of AOAC International ◽

10.1093/jaoac/93.2.549 ◽

2010 ◽

Vol 93 (2) ◽

pp. 549-555 ◽

Cited By ~ 2

Author(s):

Gamal Abdel Hafiz Mostafa ◽

Mohamed Hefnawy ◽

Abdulrahman Al-Majed

Keyword(s):

Direct Determination ◽

Pharmaceutical Preparations ◽

Ion Association ◽

Phosphomolybdic Acid ◽

Hplc Method ◽

Pvc Membrane ◽

Selective Determination ◽

Response Characteristics ◽

Sodium Tetraphenyl Borate

Abstract The construction and electrochemical response characteristics of polyvinylchloride (PVC) membrane sensors for donepezil HCl (DP) are described. The sensing membranes incorporated ion-association complexes of DP cation and sodium tetraphenyl borate (sensor 1), phosphomolybdic acid (sensor 2), or phosphotungstic acid (sensor 3) as electroactive materials. The sensors displayed a fast, stable, and near-Nernstian response over a relatively wide DP concentration range (1 102 to 1 106 M), with cationic slopes of 53.0, 54.0, and 51.0 mV/ concentration decade over a pH range of 4.0 to 8.0. The sensors showed good discrimination of DP from several inorganic and organic compounds. The direct determination of 2.54000.0 g/mL DP showed average recoveries of 99.0, 99.5, and 98.5, and mean RSDs of 1.6, 1.5, and 1.7 at 100.0 g/mL for sensors 1, 2, and 3, respectively. The proposed sensors have been applied for direct determination of DP in two pharmaceutical preparations. The results obtained for determination of DP in tablets using the proposed sensors compared favorably with those obtained using an HPLC method. The sensors have been used as indicator electrodes for potentiometric titration of DP.

Download Full-text