Research On Oxidation Behavior And Mechanism Of Hypochlorous Acid On Phospholipids At Air-Liquid Interface

Inorganic chlorine-containing disinfectants with sodium hypochlorite as the main component have been widely used in disinfection in many industries for many years,and the discharge of hypochlorous acid generated by cleaning activities makes sodium hypochlorite cleaning and disinfection activities a potential source of atmospheric environmental pollution.As we all know,hypochlorous acid is produced in the body by myeloperoxidase catalyzing the oxidation of hydrogen peroxide and chloride.It is the main strong oxidant produced by cells to kill bacteria and other invading pathogens.At present,the research on the reaction of hypochlorous acid and phospholipids in the body phase has become mature,but there are very few studies on the reaction of hypochlorous acid to the air-liquid interface of phospholipids in the environment.Therefore,exploring the oxidation reaction process of hypochlorous acid to phospholipids under interface conditions and deriving the reaction mechanism have important reference value for evaluating the harmfulness of hypochlorous acid.This topic uses a small ultrasonic transducer with a diameter of 10 mm,a frequency of 40 k Hz,and an emission wavelength of 8.65 mm(25℃)to build an ultrasonic levitation device.Provide a basis for the research of gas-liquid interface reaction.The constructed acoustic levitation device can suspend samples with a diameter less than 4 mm(half wavelength),providing a reaction platform for the study of the oxidation of phospholipids by hypochlorous acid at the air-liquid interface.The platform has good applicability for the study of interface reactions,and its reaction parameters are optimized to achieve the best interface reaction efficiency.The nanoelectrospray ion source was selected,and the acoustic suspension-nanoelectrospray mass spectrometry was constructed to detect and analyze the oxidation reaction,and explore the oxidation reaction of hypochlorous acid on the phospholipid at the air-liquid interface.Using acoustic levitation-nano-electrospray mass spectrometry,the oxidation status of DPPE,POPG,and DOPG at different exposure times of hypochlorous acid was explored in negative mode.By studying the changes of the non-equilibrium dynamic system whose properties change with time,the reaction rate of hypochlorous acid on the chemical oxidation process of phospholipids at the air-liquid interface is calculated.The changes of the reaction substrate and main reaction products over time are analyzed,the reaction order and reaction rate constant of the reaction are explored,the gas absorption coefficient of suspended phospholipid droplets is calculated,and the gas absorption coefficient of other solutions is compared to measure the gas-The rate of oxidation of phospholipids by hypochlorous acid at the liquid interface.Finally,through the mass spectrometry data collection of the reaction solution and the secondary mass spectrometry analysis of the reactants and reaction products,the oxidation behavior and mechanism of hypochlorous acid at the air-liquid interface on three different phospholipids,DPPE,POPG,and DOPG,were studied in detail.The mechanism of the reaction between HOCl and C=C bond is given,which is also applicable to the collision of HOCl with different lipid membrane suspension droplets.From the three aspects of the sensitivity of saturated alkyl lipid chain,whether the C=C bond is oxidized and whether the oxygen functional group is increased,and whether the double bond is broken to form small molecules such as acid and aldehyde when the lipid is densely packed,the difference between HOCl and lipid The interface characteristics of the qualitative material are compared with O3 and ·OH which are generally present in the gas phase,and it is concluded that the oxidation behavior of HOCl and lipids is significantly different from that of O3 and ·OH.The acoustic levitation device has well formed the gas-liquid interface conditions,which provides a good platform for the research of the gas-liquid interface reaction.Combined with nano-electrospray mass spectrometry,the reaction was detected accurately and highly sensitively,and the kinetic analysis of the oxidation reaction of hypochlorous acid on different phospholipids at the gas-liquid interface was completed.Using the second-level mass spectrometry analysis,the interface reaction mechanism was inferred.The field of health impact assessment caused by the increase of hypochlorous acid content in the environment has important reference value.