Study On The Quality Evaluation Of Moxa Based On Thermal Behavior Analysis And Its Correlation With Lignin

BackgroundMoxibustion therapy refers to a method of igniting moxa floss and placing it on acupoints or specific parts of the body to stimulate the menstrual energy to adjust the disordered physiological functions,thereby achieving the purpose of preventing and curing diseases.At present,most researches on the quality of moxa are focused on the volatile oil of moxa and the components of moxa smoke.The volatile oil and smoke are collected and analyzed independently by extraction and separation technology.These methods are more accurate for the determination of volatile substances released during the combustion,but it is more difficult to accurately determine the semi-volatile and difficult-to-volatile substances that are closely related to the temperature and sufficiency of moxa burning.In addition,for some ingredients that work through transdermal absorption and other methods,it is inevitable to be insufficient to analyze only volatile oil and smoke.Thermogravimetric analysis(TGA)and Pyrolysis-Gas chromatography-Mass spectrometry(Py-GC/MS)are common methods in the field of material analysis.The thermogravimetric analysis method can provide physical properties and chemical properties of the relevant substances by observing and measuring the change in mass of the sample as the temperature increases and the time increases And solid-gas reaction and other related information.Pyrolysis means that under an inert atmosphere,the chemical bond in a substance is broken by a very strong input heat flow,causing it to decompose under heat,and a large amount of chemical components are precipitated in a very short time.The main advantage of pyrolysis technology is that it can fully release the chemical components in the material,and the overall grasp of the type and content of the product through different pyrolysis forms or heating rates.Lignin is the main compound that forms the plant cell wall,and it has an impact on various physical and chemical properties of plant fibers.However,the complexity,diversity and variability of the structure of lignin make its research in the field of medicinal plants scarce.The research on moxa-related lignin is almost zero.Through the team's previous research,we found that some characteristics of lignin have many similarities with moxa,so this article intends to discuss it from the perspective of lignin.ObjectivesThis subject takes moxa made in different years and different proportions and commercially available moxa as the research objects.Through thermogravimetric analysis and pyrolysis studies,it provides new methods for the quality evaluation of moxa.At the same time,The subject uses lignin,a new indicator,to introduce the quantitative analysis and thermal behavior analysis results of lignin into the moxa quality rating system to further improve the moxa quality evaluation method and standardize the moxa market.Methods1.Sample collection and preparation.A total of nine different moxa samples were collected,three of which were machine-made moxa(hereinafter referred to as moxa moxa)manufactured by Henan Nanyang Lvying Wormwood Biological Products Co.,Ltd.,and six samples Commercially available moxa purchased online.The manufacturing process of the moxa wormwood is to take three years of wormwood,pick up the stems,put them into the crusher and crash them into the drum screen,and use the wind of the hair dryer to push the wormwood crushed material through the deflector.Deposited on the bottom,the upper part is the finished moxa.The storage period of the three mechanism moxa samples is three years,and the processing ratios are 3:1,10:1 and 30:1.The six commercially available moxa samples were purchased from major e-commerce platforms,with different origins,storage years,and processing ratios.All samples were dried at 100?,stored at room temperature and protected from light until use.2.Thermogravimetric analysis(TGA).The thermogravimetric analyzer used in the experiment is SDT Q600(TA Company,USA),repeat the experiment 3 times to eliminate system errors,and add a group of blank experiments to calibrate the results.The temperature is controlled by temperature programming and the thermobalance is weighed and recorded continuously.Taking the temperature as the abscissa and the mass and mass change rate of the ordinate,the TG and DTG curves of the sample are obtained.3.Pyrolysis-GC/MS.The Pyroprobe 6150 pyrolyzer produced by the US CDS company and the Clarus 680-SQ 8T gas chromatograph mass spectrometer produced by PerkinElmer were used in the experiment.Refer to the relevant information in the NIST and MAINLIB databases and use manual analysis to determine the chemical name and structure of the compounds in the test sample.Then use the peak area normalization method to obtain each peak The area percentage of each is used to derive the relative content of each cracked product.4.Extraction and characterization of lignin.Place the moxa sample in a vibrating ball mill and ball mill at room temperature for 6 hours until it is crushed to a powder of 80-100 mesh.Weigh the sample powder and add acetone to soak overnight.Place in a round bottom flask and add 300 ml of 9:1(v/v)dioxane/water solution,place in an electronic temperature control heating mantle,boil at 220?,maintain at 180? and heat at reflux for 10 hours.The filtrate was collected by rotary evaporation,and when concentrated to 15 ml,10 times volume of deionized water was added,and crude lignin was obtained after centrifugation.Pyridine,acetic acid,and deionized water were mixed at a ratio of 9:1:4,mixed with crude lignin and allowed to stand for 1 hour.Use a separatory funnel and chloroform for extraction.The extract is rotary evaporated to 5-10 ml and 15 times the volume of ether is added.After centrifugation,diethyl ether was added to the solid and washing was repeated 5 times until there was no pyridine smell in the precipitate.After drying,moxa lignin was obtained.Dissolve lignin in 5 ml dioxane/water(v/v8:2)solution,and prepare lignin standard with the same dioxane/water solution as standard solution,UV spectrophotometer 200-500 Scan at nm.5.Quantitative study of lignin.Weigh 0.5g sample into the volumetric flask,the mass is recorded as M,add acetone and soak overnight.The sample was transferred to a crucible and suction filtered in a cold leaching device until colorless.Place on a fiber extractor,heat and boil for 1 hour,then suction filter until no foam.Place in a cold leaching device and rinse twice with acetone.Add 72%sulfuric acid to soak for 3 hours,then rinse until no acid.Place in a vacuum desiccator to dry,weigh after balancing,and the mass is recorded as M105 ?.Put it in a muffle furnace for ashing,weigh after balance,and the mass is recorded as M510?.Lignin content calculation formula:(M105?-M510?)/M × 100%.6.Inductively coupled plasma mass spectrometry(ICP-MS).Weigh 0.2 g of sample into the digestion tank,add 5 mL of concentrated nitric acid and 2 ml of hydrogen peroxide and digest.Put the completely digested sample on the electronic temperature-controlled heating plate.When the yellow-brown smoke has evaporated completely and the liquid has 2-3 ml remaining,remove it and transfer it to a 50 ml volumetric flask.Solution.Results1.The thermal weight loss of moxa floss is generally within a wide temperature range.In the main weightlessness stage of moxa floss,a high proportion of samples in moxa floss have a higher weight loss rate and worse thermal stability.Under the same conditions,it is easier to decompose and the pyrolysis components are more abundant.Among the commercially available moxa samples,the long-year samples have a higher weight loss rate and poorer thermal stability,but there is no obvious rule in the processing ratio.2.Nine samples of pyrolysis of moxa were detected for Sarcosine and Methyl acetoacetate(MAA),and their relative content was very high.The total ratio of the two was more than a quarter,and the mechanism was The content of sarcosine and MAA in cashmere samples increased with the increase of processing ratio;linoleic acid/linoleic acid,palmitic acid(Hexadecanoic acid)and nicotinic acid were detected in several samples)Etc.;Hypotaurine(Hypotaurine)was detected in 30:1 mechanism moxa;acetic acid(Acetic acid)and acetic anhydride(Acetic anhydride)were basically detected in 9 samples,the relative content was basically above 8%.In addition,phenol(Phenol)and hydroquinone(Hydroquinone)were detected in the three mechanism moxa samples,both of which decreased with the increase of processing ratio.The catechol(Catechol)and p-methylphenol(Mequinol)were also detected in the 3:1 sample.In addition to the above ingredients,among the three three-year commercially available moxa samples,benzene(Bezene)was detected in two samples 1,2 and toluene(Toluene)was detected in two samples 1,3.3.This study integrates and improves the existing methods of other industries or crops,and innovatively proposes the extraction method of lignin from lignin,and it is characterized as lignin by ultraviolet absorption spectrum analysis,which is typical Benzene ring absorption peak.4.3:1 mechanism lignin content in linter is 11.6%,10:1 is 14.8%,30:1 is lignin content is 24.3%.The lignin content of the six commercially available moxa samples was around 10%.5.The experiment found that the thermal behavior of lignin extracted from different proportions of moxa was not significantly different,and the range of thermal weight loss was between 200? and 480?.The lignin sample has a series of overlapping weightlessness peaks between 149?-500?,which is its main weightlessness stage.6.Experiment analyzed the contents of five heavy metal elements in arsenic(As),chromium(Cr),cadmium(Cd),mercury(Hg),and lead(Pb).Among them,Cr,As,The Pb element content is within the specified value,the Hg element exceeding standard rate is 11.1%,and the Cd element exceeding standard rate is 44.4%.Conclusion1.Generally speaking,moxa wool,with high processing ratio and long storage year under the same conditions is easier to decompose and is more conducive to the decomposition and release of its chemical components,and the lower percentage and more short-term moxa wool impurities.Under the same conditions,commercially available moxa is more difficult to decompose than mechanical moxa and contains more impurities.2.Moxa floss with a higher processing ratio has a lower component safety than moxa,and the harmful substances produced by combustion are less in terms of types and contents.The harmful components detected in the commercially available moxa samples are higher in type and content than the mechanical moxa samples,and there is a large gap in safety from the moxa samples.3.The improved and innovative lignin extraction method is reliable and the results are stable.The extracted lignin has a high degree of retention of the natural lignin structure and can be used for subsequent thermogravimetric analysis and pyrolysis experiments.4.The results showed that the lignin content of the moxa moxa samples increased with the increase of the processing ratio,the lignin content of 3:1 moxa was the lowest,and the content of 30:1 was the highest.The lignin content difference between the 3:1 and 10:1 samples is small,but it is very different from the 30:1 sample.Combined with the results of pyrolysis,it is speculated that the effective ingredients and the onset of moxa may be related to lignin.further research.5.The main weightlessness stages of lignin and moxa almost completely overlap,which runs through the whole pyrolysis process of moxa.All kinds of effective substances in moxa are generated and released during their main weightlessness stage,which is also the main stage where lignin undergoes side chain and aryl ether bond breakage and separation and generates various phenols,aldehydes and alcohols.6.Artemisia argyi has a certain enrichment capacity for heavy metal cadmium,but in general its heavy metal content is within the specified range,and its safety is better.