Detection Of Methylglyoxal Research Articles

Intrinsic Raman signal amplification for rapid identification and detection of methylglyoxal in manuka honey

Methylglyoxal (MGO) is the primary material basis for the non-peroxide antibacterial activity (NPA) of manuka honey from New Zealand. Therefore, it is necessary to identify the quality or discriminate the grade of honey because no all manuka honeys on the market display the NPA. The current routine method employed for the detection of MGO involves high-performance liquid chromatography (HPLC) test. However, it requires long time (∼8 h) for sample derivatization. Herein, we report an intrinsic Raman signal amplification strategy for the rapid identification and detection of MGO by using silver-coated gold nanoparticles (Au@Ag NPs) along with a high selective surface-enhanced Raman scattering (SERS) probe 8-thioguanosine (8-TG). 8-TG is synthesized via the derivatization of 8-bromoguanosine (8-BG) with thiourea, and its Raman peak assignments were confirmed by computer simulation. The detection is performed through the Raman intensity ratio (I631/I700) variation of N2-(1-carboxyethyl)-thioguanosine (CETG) formed by the reaction between 8-TG and MGO on surface of Au@Ag NPs, where one CETG Raman intensity at 631 cm−1 increases while the other one at 700 cm−1 decreases oppositely. The opposite change not only yields an intrinsic Raman signal amplification, but also provides built-in correction. As a result, the proposed SERS method exhibits high sensitivity and accuracy. In addition, the whole analytical test is achieved within ∼20 min. The method can be used for the fast detection of MGO in manuka honey and discrimination of the honey grade.

Nanohybrid sensor for simple, cheap, and sensitive electrochemical recognition and detection of methylglyoxal as chemical markers

We successfully designed a nanohybrid sensor based on carboxyl-functionalized multi-walled carbon nanotubes (MWCNTs-COOH) co-functionalized with both carboxymethyl cellulose (CMC) and chitosan nanosphere (CSN) for a simple, low-cost, highly-sensitive voltammetric recognition and determination of Methylglyoxal (MG) as chemical marker of New Zealand Manuka honey. Morphology and structure revealed that CSN-CMC was adhered onto MWCNTs-COOH surface. Interactions between modifying layers and both reduction potential and response mechanism of MG were confirmed by theoretical calculations. The nanohybrid sensor displayed large electrochemical effective area, excellent electrocatalytic activity, a wide linear range of 5×10−8–8×10−4mol/L, a low detection limit of 9.6×10−9mol/L, and good stability as well as selectivity under the optimal conditions. The applicability of the fabricated sensor was assessed using three Chinese honeys and one New Zealand Manuka honey. This work will put forward a new strategy for electrochemical recognition and detection of MG as chemical markers of many agricultural production, processing, products and food and a new alternative tool for assessing economically motivated fraud and counterfeit issues in Chinese honey markets using electrochemical nanohybrid sensor.

Electron Attachment Reaction Ionization of Gas-Phase Methylglyoxal.

Methylglyoxal (MGLY) plays a significant role in atmospheric chemistry by serving as a key contributor to the formation of active free radicals, ozone, and secondary organic aerosol. Detection of MGLY by traditional chemical ionization such as proton-transfer reaction has several shortcomings such as parent molecule fragmentation. In this study, an electron attachment reaction (EAR) ionization method has been developed for the effective detection of MGLY. Almost no fragmentation was observed during the EAR. The generation of MGLY- anion in the EAR was further confirmed by cryogenic photoelectron imaging spectroscopy. The concentration of MGLY can be calibrated by using dibromomethane (CH2Br2) as reference gas. The detection sensitivity of MGLY was estimated to be (100 ± 2) mV/ppbv (parts per billion by volume). The O2, H2O, CO2, and trace gases in ambient air have no obvious effects on the detection of MGLY- anion by the EAR ionization method.

Determination of methylglyoxal in Manuka honey of New Zealand by high performance liquid chromatography

An HPLC method was developed for the determination of methylglyoxal in Manuka honey of New Zealand. The honey sample was dissolved in water and mixed with o-phenylenediamine solution for derivatization. After the reaction for at least 8 h in the dark at room temperature, the solution was filtered with 0.22 microm membrane and injected into an HPLC system for analysis. The separation was carried out on a Kromasil reversed phase column with gradient elution. The mobile phases were methanol and 0. 1% (v/v) acetic acid aqueous solution. The detection wavelength was 318 nm. The external standard method was used for quantitation. The linear range of methylglyoxal was 1-50 mg/L with a correlation coefficient of 0. 999 9. The LOD (S/N = 3) and LOQ (S/N = 10) were 0.02 mg/L and 0.06 mg/L, respectively. The recoveries at the spiked levels of 50, 100, 200 mg/kg were 98.3%-101.5% and the RSDs (n = 5) were less than 5%. The derivative of methylglyoxal was stable within 24 h. The results showed that the pretreatment of this method is simple and the sensitivity, the recovery and repeatability are good. This method can be used for the quality control of Manuka honey of New Zealand, and also for the detection of methylglyoxal in Chinese honey.

Voltammetric detection of the α-dicarbonyl compound: Methylglyoxal as a flavoring agent in wine and beer

A simple, rapid and highly selective method for the determination of the most abundant α-dicarbonyl compound in wine and beer has been developed for the first time by employing square wave voltammetry. A novel electrochemical sensor, based on the electrodeposition of platinum nanoparticles onto single wall carbon nanotubes that were cast on a glassy carbon electrode (GCE) substrate, is presented in this paper. This modified electrode exhibited excellent catalytic activity in the electroreduction of methylglyoxal, showing much higher peak currents than those measured on an unmodified GCE. The effects of different experimental and instrumental parameters, such as solution pH and square wave frequency, were examined. The reduction peak current showed a linear range of from 0.1×10−6 to 100×10−6M with a 0.9979 correlation coefficient; and a low detection limit of 2.8×10−9M was also obtained. The proposed methodology was successfully applied to the quantitative analysis of methylglyoxal in wine and beer samples. The developed sensor possesses advantageous properties such as a high active surface area, stability, and rapid electron transfer rate, which cumulatively demonstrate high performance toward the electrocatalytic reduction and detection of methylglyoxal.

Detection of Methylglyoxal as a Degradation Product of DNA and Nucleic Acid Components Treated with Strong Acid

The 1,2-diaminobenzene derivatization assay for methylglyoxal in biological systems involves the use of perchloric acid, both as a deproteinizing agent and to prevent the spontaneous formation of methylglyoxal from glycolytic pathway intermediates. However, while using a modification of the standard literature assay to measure methylglyoxal in Chinese hamster ovary cells, we found that oxidation of nucleic acids and related compounds by perchloric or trichloroacetic acid results in the formation of methylglyoxal. Compounds containing 2-deoxyribose gave higher levels of methylglyoxal than those containing ribose; purine nucleotides and deoxynucleotides gave more methylglyoxal than did the pyrimidines. Nucleic acids were the most susceptible to degradation, with 12-fold more methylglyoxal being formed from DNA than RNA. Oxidation of nucleic acids increased with higher temperatures and with decreasing nucleic acid fragment size. Another product of nucleic acid oxidation was 2,3-butanedione, the 1,2-diaminobenzene derivative of which is sometimes used as an internal standard during methylglyoxal measurement. Unless accounted for during the assay procedure, the generation of methylglyoxal and 2,3-butanedione due to the oxidation of nucleic acids may lead to substantial errors in the determination of methylglyoxal concentrations in biological systems.

Rubber. XVII. Detection of Methylglyoxal and the Ozone Cleavage of Rubber

Abstract Since the work of Harries, the question whether methylglyoxal is found in the ozone cleavage of rubber has played an important part in explaining the constitution of this hydrocarbon. Since Harries found no methylglyoxal, he assumed a cyclic formation of isopentene, —CH2.C(CH 3):CH.CH2—, residue sand the absence of a corresponding —CH:C(CH3).CH:CH2 end group, which would necessarily yield methylglyoxal. Nevertheless, in view of the probability that a very long open chain is present in the rubber molecule, the necessity again arose of trying to identify methylglyoxal as n product of the ozone cleavage. This involved the problem of detecting extremely small quantities, since the length of the chain might be very great. Provided that no secondary reaction takes place, the yield of methylglyoxal, if formed, should give information about the length of the chains. If, for example, in the cleavage 0.1 per cent of the carbon skeleton were to appear as methylglyoxal, it might be concluded from the three carbon atoms that the chain length is 1000 times greater, viz., 3000 carbon atoms, or 600 isoprene units. These investigations have been undertaken as a conclusion of our earlier work on the ozone cleavage of rubber, in which approximately 90 per cent of the cleavage products were obtained as compounds of the levulinic aldehyde (acid) series.