Lipids hydroperoxide determination

FerrocenecarboxyUc acid, lipid hydroperoxide determination, 686-7 Ferrocenol, bis(trimethylsilyl) peroxide reactions, 798-800 Ferrocenol esters, preparation, 800 Ferrocyanide, performic acid determination, 699... 

Isolimonene, artemisinin synthesis, 277 Isoluminol, lipid hydroperoxide determination, 680, 681 Isomerization aUyhc alcohols, 789-90 y-chlordene, 728... 

Grau, A., Codony, R., Refecas, M., Barroeta, A.C., and Guardiola, F. 2000. Lipid hydroperoxide determination in dark chicken meat through a ferrous oxidation-xylenol orange method, J. Agric. Food Chem., 48(9), 4136. 

Lovaas, E. 1992. A sensitive spectrophotometric method for lipid hydroperoxide determination, JAOCS, 69(8), 111. 

The first FI-CL system for lipid hydroperoxide determination, published in 1993, was based on luminol as the CL reagent and microperoxidase as the catalyst. The optimized system was used for measuring lipid hydroperoxides in native low-density lipoprotein (LDL) (Cominacini et al. 1993). The FI-CL system consisted of two pumps, an autosampler, and a chemiluminescent detector with a T-mixing coil. Samples were injected by using an autosampler and mixed with luminescent reagent (3 (iM luminol and 1 xM microperoxidase in 0.1 M carbonate buffer, pH 10). The calibration curve was obtained using linoleic acid, and a detection limit of 3 pmol linoleic acid hydroperoxide was reached. 

This test is used for both in vitro and in vivo determinations. It involves reacting thiobarbituric acid (TBA) with malondialdehyde (MDA), produced by lipid hydroperoxide decomposition, to form a red chromophore with peak absorbance at 532 nm (Fig. 10.1). The TBARS reaction is not specific. Many other substances, including other alkanals, proteins, sucrose, or urea, may react with TBA to form colored species that can interfere with this assay. 

Luminol derivatives produce emission of light by oxidation with oxygen and hydrogen peroxide under alkaline conditions. By utilizing this reaction, peroxides such as hydrogen peroxide and lipid hydroperoxides can be determined after HPLC separation. Metal ions [e.g., iron(II), cobalt(II), etc.] catalyzing the luminol CL reaction can also be determined. 

Lipid Peroxidation Chemistry, 105, 273 overview of methods used for detecting lipid peroxidation, 105, 283 chemical methods for the detection of lipid hydroperoxides, 105, 293 comparative studies on different methods of malonaldehyde determination, 105, 299 concentrating ethane from breath to monitor lipid peroxidation in vivo, 105, 305. 

Bioxytech LPO-560 Colorimetric determination of lipid hydroperoxides based on the FOX assay . ... 

A correlation may be established between the concentration of oxidized lipids and the TEARS value, expressed as MDA equivalents, in uM units. Correction is due in some cases for the interference by dyes or other factors. For example, the presence of anthocyanins in red cabbage leaves or turbiditjf causes overestimation of lipid hydroperoxides in plant tissue by the TEARS method. TEARS was used to assert the level of endogenous peroxides in hypo- and hyperthyroidism, both conditions being characterized by low lipid and lipoprotein plasma levels and enhanced oxidative metabolism . In a procedure for determination of TEARS in edible oils, the sample is placed in a centrifuge at 12000 g before measuring at 532 nm (e = 1.56 x 10 M cm ) . A usual procedure for determination of TEARS in certain complex matrices involves steam distillation of the aldehydes responsible for the value, instead of extraction. In nitrite-cured meats, excess nitrite may cause nitrosation of MDA, thus interfering with distillation. To avoid this interference sulfanilamide is added, which is converted to a diazonium salt and... 

Hydroperoxides may be determined by measuring at 290 nm (e = 44100 M cm ) or 360 nm (e = 28000 cm ) the concentration of 13 formed in the presence of a large excess of ions. The reaction may be too slow for practical purposes, unless a catalyst is present. For example, an assay for lipid hydroperoxides conducted without a catalyst may require several measurements every 6 min until the absorbance reaches a maximum. Exclusion of air from the sample cuvette is important. The method is about 1000-fold more sensitive than thiosulfate titration The iodometric method with UVD at 360 was adopted for detecting the presence of hydroperoxides derived from protein, peptide or amino acid substrates subjected to y-radiation, after destroying the generated H2O2 with catalase. ... 

A kit in Table 2 is used to determine lipid hydroperoxides by producing Methylene Blue (91) according to equation 29 and measuring the absorbance at 675 run. The assay was applied to determine the concentration of lipid hydroperoxides in serum of patients infected with HIV . 

The CLD methods for HPLC using isoluminol (190) with microperoxidase catalysis, for determination of lipid hydroperoxides in clinical fluids, have been reviewed. Determination of phospholipids hydroperoxides by luminol (124) CL has been reviewed . A fast RP-HPLC method (retention times 1 to 2 min) for determination of hydroperoxides and other peroxide compounds includes UVD, which is not always effective, and CLD, attained on injection of luminol (124), the CL reagent (Scheme 3), hemin (75a), a catalyst, and NaOH to raise the pH of the solution. A FLD cell may act as CLD cell if the excitation source is turned off. The selectivity of CLD is of advantage over UVD in industrial analysis thus, for example, UVD of a sample from a phenol production line based on cumene oxidation (equation 13) shows peaks for cumyl hydroperoxide (27), unreacted cumene, cumyl alcohol and acetophenone, whereas CLD shows only the 27 peak. The... 

A procedure for determination of lipid hydroperoxides in human plasma is based on kinetic measurement of the CL of luminol (124) with hemin (75a) catalysis . CLD of microperoxidase-catalyzed oxidation of luminol (124) or isoluminol (190) was applied to detection and determination of amino acid hydroperoxides after exposure to UV and y-irradiation A method for determination of hydroperoxides in the phospholipids of cultured cells uses isoluminol (190) and microperoxidase as catalyst " . Simultaneous determination of phosphatidylcholine hydroperoxides and cholesteryl ester hydroperoxides in human serum is carried out by quantitative extraction of the lipids, HPLC separation by column switching and CLD using isoluminol (190) with microperoxidase catalysis . ... 

A highly selective method for determination of lipid hydroperoxides is based on the oxidation of ferrocenecarboxylic acid (201) to the corresponding ferrocenium compound (202), as shown in equation 69, followed by amperometric reduction of this complex with a GCE set at —100 mV vs. SCSE, in phosphate buffer at pH 5.5. The method is insensitive to dissolved oxygen and no interference is observed, either from reductors such as ascorbic acid (22) or uric acid (29) nor from other hydroperoxides such as H2O2 and f-BuOOH at the 1 xM concentration level. At this concentration, a slight interference is observed for cumyl hydroperoxide (27) and 2-butanone peroxide (46 4- 47). The LOD... 

Cerebral ischemia, lipid hydroperoxides, 612 Cerium(lll), hydrogen peroxide determination, 640... 

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