Biomedical subjects

Rahel Girmai Bokretsion

Publications and source records attributed to Rahel Girmai Bokretsion.

5 recordsLinked to original sources

PubMed2006

Simultaneous detection of creatine and creatinine using a sequential injection analysis/biosensor system.

Carbon paste based biosensors for the determination of creatine and creatinine have been integrated into a sequential injection system. Applying the multi-enzyme sequence of creatininase (CA), and/or creatinase (CI) and sarcosine oxidase (SO), hydrogen peroxide has been detected amperometrically. The linear concentration ranges are of pmol/L to nmol/L magnitude, with very low limits of detection. The proposed SIA system can be utilized reliably for the on-line simultaneous detection of creatine and creatinine in pharmaceutical products, as well as in serum samples, with a rate of 34 samples per hour and RSD values better than 0.16% (n=10).

Amidohydrolases↗

PubMed2003

Simultaneous determination of L- and D-methotrexate using a sequential injection analysis/amperometric biosensors system.

A sequential injection analysis (SIA) is proposed for the simultaneous determination of L- and D-methotrexate (Mtx) using amperometric biosensors as detectors. A SIA system is proposed due to the highest precision and accuracy and lower consumption of sample and buffer. The amperometric biosensors used as detectors in SIA system were based on L-amino acid oxidase (L-AAOD) or/and L-glutamate oxidase (L-Glox) and horseradish peroxidase (HRP) for the assay of L-Mtx and D-amino acid oxidase (D-AAOD) and HRP for the assay of D-Mtx were selected. The linear concentration ranges are of pmol/l to nmol/l magnitude order, with very low limits of detection. The SIA/biosensors system can be used reliably on-line in synthesis process control, for the simultaneous assay of L- and D-Mtx with a frequency of 34 samples per hour.

Amino Acid Oxidoreductases↗

PubMed2003

Simultaneous determination of L- and D-carnitine using a sequential injection analysis/amperometric biosensors system.

A sequential injection analysis (SIA) system is described for the simultaneous determination of L-and D-carnitine using amperometric biosensors as detectors. The SIA system was used, because of its high precision, accuracy and low sample and buffer consumption. The biosensors were designed using physical and chemical immobilization of L-amino acid oxidase and horseradish peroxidase (HRP) for the assay of L- carnitine, and D-amino acid oxidase and HRP for the assay of D-carnitine. The linear concentration ranges are in the pmol/l to nmol/l magnitude order, with very low limits of detection. The biosensors/SIA system was used reliably for on-line process control of the enantiopurity of carnitine with a frequency of 34 samples per hour.

Biosensing Techniques↗

PubMed2003

Diamond paste based immunosensor for the determination of azidothymidine.

An amperometric immunosensor, based on diamond paste (diamond powder and paraffin oil), has been constructed for the assay of azidothymidine (AZT). The diamond paste is impregnated with anti-AZT. The immunosensor can be used reliably for the assay of azidothymidine in its pharmaceutical formulations. The potential used for azidothymidine assay was + 240 mV vs. Ag/AgCl electrode. The surface of the immunosensor can be regenerated by simply polishing, thereby obtaining fresh immunocomposite ready to be used in a new assay. The new amperometric immunosensor, based on diamond paste, gives reliable results for the assay of AZT as raw material and from its pharmaceutical formulation.

Diamond↗

PubMed2003

Biosensors for the determination of ortho-acetyl-L-carnitine. Their utilization as detectors in a sequential injection analysis system.

In order to determine ortho-acetyl-L-carnitine, two biosensors were proposed. The biosensors were designed using physical immobilization of L-amino acid oxidase (L-AAOD) and horseradish peroxidase (HRP). Electrode characteristics were obtained and compared for the two carbon paste (graphite powder and paraffin oil) biosensors. The linear concentration ranges for the proposed biosensors were in the ranges of fmol/L to nmol/L, magnitude order with low limits of detection. Due to their reliability, the biosensors were used as detectors in a sequential injection analysis system, and gave reliable results for on-line assay of ortho-acetyl-L-carnitine in synthesis process control with a frequency of 75 samples per hour.

Acetylcarnitine↗