Scanning homocysteine

Wang et al. [64] proposed the use of CNTPE for the detection of homocysteine. Voltammetric experiments of 160 pM homocysteine at CNTPE showed a well defined signal at 0.28 V that reached a maximum at 0.64 V. This peak current depended linearly with the square root of the scan rate. On the contrary, at CPE only a slight increase in the oxidation current was obtained at 0.40 V, with no peak current definition. A linear relationship between the voltammetric current and homocystein concentration at 0.64 V was observed between 20 and 180 pM, with a detection limit of 17.3 pM. Amperometric experiments were also performed at a potential of 0.70 V and a linear relationship between steady-state currents and homocystein concentration was obtained... 

Figure 55-2 Multi-analyte approach to the prenatal diagnosis of methylmalonic acidemia (cb/C complementation group) by metabolite analysis in ceil-free supernatant of amniotic fluid collected at 16 weeks of gestational age. The symbol marks internal standards. A, Determination of total homocysteine by LC-MS/MS (selected reaction monitoring, SRM, transition m/z 136 to m/z 90 and m/z 140 to m/z 94 for the d -labeled internal standard). The concentration of total homocysteine was l5.7pmol/L (0.7 to 2.0pmol/L). B, Determination of methylmalonic acid by LC-MS/MS (SRM, transition m/z 231 to m/z 119 and m/z 234 to m/z 122 for the d3-labeled internal standard). The concentration of methylmalonic acid was 8.7pmol/L, the reference interval for 16 to 19 weeks of gestational age is 0.2 to 0.7)j,mol/L. C, Determination of propionylcarnitine by LC-MS/MS (parent of m/z 85 scan, the [M+H] ion of C3 is m/z 274, m/z 277 for the interna standard). The concentration was 5.6pmol/L (i.5 to l.8pmoi/L),the C3/C4 ratio was 6.9 (0.9 to 2.6).

Holter monitoring Homocysteine Isonitrile scan Lactic dehydrogenase Lipoproteins MUGA scan Myoglobin Pericardiocentesis Plethysmography arterial venous... 

Prins ND, Den Heijer T, Hofman A, Koudstaal PJ, Jolles J, Clarke R, Breteler M Rotterdam Scan Study. Homocysteine and cognitive function in the elderly the Rotterdam Scan Study. Neurology 2002 59 1375-1380. 

Vermeer SE, van Dijk EJ, Koudstaal PJ, Oudkerk M, Hofman A, Qarke R, Breteler MM. Homocysteine, silent brain infarcts, and white matter lesions The Rotterdam Scan Study. Ann Neurol 2002 51 285-289. 

Siddiqi et al. (1995) separated alpha amino acids on tin(IV) selenoarsenate layers with a mobile phase of dimethyl sulfoxide (DMSO). Petrovic and Kastelan-Macan (1995) used scanning densitometry for the validation of quantitative amino acid analysis on mixed natural zeolite—microcrystalline cellulose layers. Ohtake et al. (1995) used cellulose TLC to analyze homocysteine from dried blood spots of patients with homocystinuria. 

Fig. 15.2. Cyclic voltammograms for (I) homocysteine, (II) 0.67 mM glutathione, (III) 1.0 mM 2-mercapto ethanesulfonic acid, (IV) 10.0 mM cephalexin, at (A) BDD and (B) GC electrodes vs. Ag/AgCl in 0.1 M carbonate buffer (pH 9.2) in the presence (solid lines) and absence (dotted lines) of the analytes (scan rate, 50 mV s area of electrode, 0.07 cm ).

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