Recent Advances of Sensitive Electrochemical Sensing Platforms for Rapid Detection of Phthalate Acid Esters

As a kind of plasticizer,phthalic acid esters(PAEs)are often added to plastics to enhance elasticity,transparency,durability and prolong service life.However,it does not chemically bind to plastics and is easy to migrate to the environment.It is difficult to degrade in the environment,and it is also enriched in the human body through the food chain and respiration,which will lead to obvious adverse reactions such as decreased learning and memory function and neurobehavioral disorders.Due to the toxicity,universality and low concentration limitations of PAEs in the environment and food,it is essential to achieve rapid and sensitive detection of PAEs in soil,atmosphere,water and food.Electrochemical(EC)sensors have the advantages of simplicity,fast,low cost,portability,easy operation,high specificity and high sensitivity,so they are applied for the detection of PAEs.Although there are a large number of studies on the detection of PAEs by EC sensors,there is no review on this aspect.In this review,we introduce the detection of PAEs from classical EC sensors,electrochemiluminescence(ECL)sensors and photo-electrochemical(PEC)sensors in the past five years.This review is beneficial to understanding the construction of EC sensors and the detection mechanism of PAEs.We also propose that the development of rapid,accurate and real-time detection methods of PAEs is key to assessing risk and preventing related diseases.

Adsorption of Phthalic Acid Esters by Humic Acid and Its Research Progress

Humic acid is rich in highly electronegative oxygen-containing organic functional groups,so it has high reactivity and can adsorb phthalic acid ester(PAEs)in the environment to reduce the risk of environmental pollution from PAEs.In this paper,the extraction,characterization and adsorption models of humic acid were reviewed,and the research status of adsorption of PAEs by humic acid was further summarized.Based on these,the feasibility and observable application prospect of humic acid as a cheap adsorbent were analyzed.

Abiotic degradation of four phthalic acid esters in aqueous phase under natural sunlight irradiation

Abiotic degradability of four phthalic acid esters （PAEs） in the aquatic phase was evaluated over a wide pH range 5-9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunlight irradiation for evaluating the degradation rate via hydrolysis or photolysis plus hydrolysis, respectively, at ambient temperature for 140 d from autumn to winter in Osaka, Japan. The efficiency of abiotic degradation of the PAEs with relatively short alkyl chains, such as butylbenzyl phthalate （BBP） and di-nbutyl phthalate （DBP）, at neutral pH was significantly lower than that in the acidic or alkaline condition. Photolysis was considered to contribute mainly to the total abiotic degradation at all pH. Neither hydrolysis nor photolysis of di-ethylhexyl phthalate （DEHP） proceeded significantly at any pH, especially hydrolysis at neutral pH was negligible. On the other hand, the degradation rate of di- isononyl phthalate （DINP） catalyzed mainly by photolysis was much higher than those of the other PAEs, and was almost completely removed during the experimental period at pH 5 and 9. As a whole, according to the half-life （t1/2） obtained in the experiments, the abiotic degradability of the PAEs was in the sequence： DINP （32-140 d） 〉 DBP （50-360 d）, BBP （58-480 d） 〉 DEHP （390-1600 d） under sunlight irradiation （via photolysis plus hydrolysis）. Although the abiotic degradation rates for BBP, DBP, and DEHP are much lower than the biodegradation rates reported, the photolysis rate for DINP is comparable to its biodegradation rate in the acidic or alkaline condition.

Biodegradability of four phthalic acid esters under anaerobic condition assessed using natural sediment

Biodegradability of di-n-butyl phthalate （DBP）, butylbenzyl phthalate （BBP）, di-ethylhexyl phthalate （DEHP）, and di-isononyl phthalate （DINP） under an anaerobic condition was evaluated using three natural sediment microcosms obtained from ponds in Osaka, which had not been significantly polluted by the chemicals. The degradabilities of the four phthalic acid esters（PAEs） were analyzed by a first-order kinetic model with a lag phase and ranked as DBP〉BBP〉〉DEHP〉DINP. The PAEs with shorter alkyl-chains, DBP and BBP, were degraded with quite short lag phases near to zero and short half-lives of a few days. The PAEs with longer alkyl-chains, DEHP and DINP, were degraded with lag phases of 5-30 d and the quite long half-lives of a couple of hundred days. Although no data was available on the anaerobic biodegradability of D1NP before this study, it was clarified that DINP can be degraded with slow degradation rates. The fact that all the three intact sediments were capable of biodegradation of the PAEs suggests that potential of anaerobic biodegradation of PAEs is widespread in the aquatic environment.

Synthesis and Primary Research on Antitumor Activity of Three New Panaxadiol Fatty Acid Esters

For making use of Ginseng resources that exhibit an antitumor activity and for finding new anticancer drugs, three new fatty acid ester compounds： 3/β-acetoxy panaxadiol （ Ⅰ ）, 3β-palmitic acid aceloxy panaxadiol （ Ⅱ ） , and 3β-octadecanoic acid aceloxy panaxadiol（ Ⅰ , Ⅱ, and m） were synthesized with panaxadiol, diacetyl oxide, palmityl chloride and stearyl chloride, and their structures were determined via MS, ^13C NMR, IR, TLC, and so on. The molar yields of the three compounds are 75.14%, 79. 08%, and 72. 57%, respectively. Meanwhile, the antitumor activity of the three new panaxadiol fatty acid ester derivatives and panaxadiol was compared by using the method of MTT. Tumor cell used was Vero cell line. Positive control was 5-FU, blank was an RPMI1640 culture medium, negative control was an RPMI1640 culture medium and the solvent for drugs to be tested. Compound Ⅰ has the strongest antitumor activity followed by panaxadiol; compounds Ⅱ and Ⅲ have similar and weakest antitumor activities. Furthermore, the antitumor activities of the panaxadiol fatty acid ester derivatives show positive correlation with the concentration of the test group, but show no relationship with the molecular weight of fatty acid. The methods that are used to synthesize the three compounds with high yields and strong antitumor activities are simple and show a great potential for meeting the needs of industrial manufacture of these drugs.

Two New Phenolic Carboxylic Acid Esters from Opuntia vulgaris

Two new phenolic carboxylic acid esters n-butyl eucomate(1) and methyl eucomate (2) and six known compounds eucomic acid(3), 3-β-acetyl-taraxerol (4), friedelin(5),lupenone(6),methyl linoleate(7) and methyl oleate(8) were isolated from the stems of Opuntia vulgaris Mill(Cactaceae). Their structures were determined on the basis of spectral methods. Compounds 3,4,6,7,8 were isolated for the first time from this plant.

Novel Phosphonoacetic Acid Derivatives.Synthesis of N-(Ethoxycarbonylmethylphosphonyl)-α-Amino Esters and-α-Amino Phosphonic Acid Esters and Their Bioactivities

A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride with amino acid ester hydrochlorides or amino phosphonates in the presence of a base. The preliminary bioassay shows that some compounds show significant anti-viral activity against tobacco mosaic virus (TMV)

QSPR Analysis of the Physicochemical Properties for Phthalic Acid Esters

Based on quantitative structure-property relationship （QSPR） of organic compounds, the molecular connectivity indices of 21 phthalic acid ester compounds were extracted. Relationship between the physicochemical properties （n-octanol/air partition coefficient, vapor pressure, water solubility） and the molecular connectivity indices of phthalic acid ester compounds have been established by multiple linear regression （MLR） method. The results showed that the zero-order valence connectivity index （0Xu） is the topology parameter which affects octanol/water partition coefficient and water solubility, and the topology parameter which affects vapor pressure is the first-order connectivity index （1X）. This indicated to a certain extent_that the molecular connectivity indices can be well used to express the quantitative relationship between the physicochemical properties and structure descriptions of phthalic acid ester compounds. The models constructed have good robustness and highly predictive capability.

Catalytic Hydrolysis of Lipophilic Amino Acid Esters by Metallomicelles as Carboxypeptidase A Models

Lipophilic complexes of macrocyclic 12-membered dioxotetraamine ligand bearing bis-hydroxy groups as functional pendants are effective catalysts for the hydrolysis of amino acid esters in micellar media, and the rate enhancement of more than 10-fold were observed.

NMR Studies of a New Binding Mode of the Amino Acid Esters by Porphyrinatozinc(Ⅱ)

The binding mode of the amino acid ethyl esters(guest) by 5 (2 carboxylphenyl) 10,15,20 triphenylporphyrinatozinc(Ⅱ)(host 1) was studied by means of 1H NMR spectra. The binding mode is the hydrogen bonding between the amino group of the guest and the carboxyl group of host 1 plus the coordination between the zinc atom of porphyrinatozinc(Ⅱ) and the carbonyl group of the guest. This is a novel binding mode of the metalloporphyrin to amino acid derivatives.

Synthesis of Macrocyclic Arsinous Acid Esters

The reactions of the his (dimethylamino) alkylarsine with dids lead to the formations ofmacrocyclic arsinous acid esters. The synthesis of title compounds was described and theirslructures were characterized by elemental analysis, IR, 1HNMR, and MS.

Anticancer Activities of Substituted Cinnamic Acid Phenethyl Esters on Human Cancer Cell Lines

Caffeic acid phenethyl ester (CAPE) and sixteen substituted cinnamic acid phenethyl esters were prepared via conventional procedures in order to test their in vitro anticancer activities by either MTT assay or SRB assay on six different human cancer cell lines. The results indicated that in the concentration of 10 μmol·L -1 the lead compound CAPE possessed anticancer activities against human HL 60, Bel 7402, and Hela cell lines, and two other compounds possessed potent anticancer activities against Bel 7402 and Hela cell lines.

Concentration and source identification of polycyclic aromatic hydrocarbons and phthalic acid esters in the surface water of the Yangtze River Delta,China

The pollution from polycyclic aromatic hydrocarbons（PAHs） and phthalic acid esters（PAEs） in the surface water of the rapidly urbanized Yangtze River Delta region was investigated.Fourteen surface water samples were collected in June 2010.Water samples were liquid-liquid extracted using methylene chloride and analyzed by gas chromatography-mass spectrometry.Concentrations of PAHs and PAEs ranged 12.9-638.1 ng/L and 61-28550 ng/L,respectively.Fluoranthene,naphthalene,pyrene,phenanthrene,di-2ethylhexyl phthalate,and di-n-butyl phthalate were the most abundant compounds in the samples.The water samples were moderately polluted with benzo[a]pyrene according to China＇s environmental quality standard for surface water.The two highest concentrations of PAHs and PAEs occurred in samples from Taihu Lake,Wuxi City and the western section of Yangchenghu Lake.Potential sources of pollution at S7 were petroleum combustion and the plastics industry,and at Yangchenghu Lake were petroleum combustion and domestic waste.Pollution in samples from the Beijing-Hangzhou Grand Canal originated from diesel engines.There were no obvious sources of pollution for the other water samples.These results can be used as reference levels for future monitoring programs of pollution from PAHs and PAEs.

Effect of dicarboxylic acid esters on the lubricity of aviation kerosene for use in CI engines

To reduce their fuel related logistic burden,North Atlantic Treaty Organization(NATO)Armed Forces are advancing the use of a single fuel for both aircraft and ground equipment.To this end,F-34(the commercial equivalent is Jet A-1)is replacing distillate diesel fuel in many applications.However,tests conducted with this kerosene type on high frequency reciprocating rig showed that this type of fuel causes unacceptable wear.This excessive wear is caused by the poor lubricity of aviation fuel.In order to make this type of fuel compatible with direct injection compression engines,seven di-carboxylic acid esters have tested to improve the lubricity of kerosene.Tribological results showed that all esters tested in this series of experiments seem to be suitable for increasing the kerosene lubricity to a satisfactory level.

Distribution and sources of polycyclic aromatic hydrocarbons and phthalic acid esters in water and surface sediment from the Three Gorges Reservoir

After the impoundment of the Three Gorges Reservoir（TGR）, the hydrological situation of the reservoir has changed greatly. The concentration and distribution of typical persistent organic pollutants in water and sediment have also changed accordingly. In this study, the concentration, distribution and potential sources of 16 polycyclic aromatic hydrocarbons（PAHs） and 6 phthalic acid esters（PAEs） during the water drawdown and impoundment periods were investigated in water and sediment from the TGR. According to our results, PAHs and PAEs showed temporal and spatial variations. The mean ΣPAH and ΣPAE concentrations in water and sediment were both higher during the water impoundment period than during the water drawdown period. The water samples from the main stream showed larger ΣPAH concentration fluctuations than those from tributaries. Both the PAH and PAE concentrations meet the Chinese national water environmental quality standard（GB 3838-2002）. PAH monomers with 2–3 rings and 4 rings were dominant in water, and 4-ring and 5–6-ring PAHs were dominant in sediment. Di-n-butyl phthalate（DBP） and di-2-ethylhexyl phthalate（DEHP）were the dominant PAE pollutants in the TGR. DBP and DEHP had the highest concentrations in water and sediment, respectively. The main source of PAHs in water from the TGR was petroleum and emissions from coal and biomass combustion, whereas the main sources of PAHs in sediments included coal and biomass combustion, petroleum, and petroleum combustion. The main source of PAEs in water was domestic waste, and the plastics and heavy chemical industries were the main sources of PAEs in sediment.

Abiotic association of phthalic acid esters with humic acid of a sludge landfill

The abiotic association between phthalic acid esters （PAEs） and humic substances （HS） in sludge landfill plays an important role in the fate and stability of PAEs. An equilibrium dialysis combined with 14C-labeling was used to study the abiotic association of two abundant PAEs （diethyl phthalate and di-n-butyl phthalate） with humic acid （HA） isolated from a sludge landfill with different stabilization times and different molecular weights. Ele- mental analysis and Fourier Transform Infrared Spectro- photometer （FTIR） suggested that high KA value of HA was related to the high aromatic content and large molecular weight of HA. The results indicated that the association strength of PAEs with HA depended on both the properties of the PAEs and the characteristics of HA. The KA values of the association were strongly dependent on solution pH, and decreased dramatically as the pH was increased from 3.0 to 9.0. The results suggested that non- specific hydrophobic interaction between PAEs and HA was the main contributor to the association of the PAEs with HA. The interactive hydrogen-bonds between the HA and the PAEs molecules may also be involved in the association.

Perspectives on ecological risks of microplastics and phthalate acid esters in crop production systems

Microplastics(MPs)and phthalate acid esters(PAEs)co-occur as emerging contaminants of global importance.Their abundance in soil is of increasing concern as plastic-intensive practices continue.Mulching with plastic films,inclusion in fertilizers,composts,sludge application,and wastewater irrigation are all major and common sources of MPs and PAEs in soil.Here,we review studies on the concentration and effects of MPs and PAEs in soil.While there is limited research on the interactions between MPs and PAEs in agroecosystems,there is evidence to suggest they could mutually affect soil ecology and plant growth.Therefore,we propose new research into 1)establishing an efficient,accurate,and simple method to quantify different types of microplastics in soils and plants;2)exploring the behavior and understanding the mechanisms of co-transfer,transformation,and interactions with soil biota(especially in vegetable production systems);3)assessing the risk and consequences of combined and discreet impacts of MPs and PAEs on plants and soil biota,and 4)preventing or reducing the transfer of MPs and PAEs into-and within-the food chain.

Mapping the structure-activity relationship of β-sitosteryl fatty acid esters in condensing phospholipid monolayers

Abstract The phase behavior of twelve synthesized β- sitosteryl fatty acid esters with acyl moieties with different chain lengths （C2：0-C18：0） and different degrees of unsaturation （C18：1-C18：3） were investigated in pure and mixed Langmuir monolayers with phospholipids. The surface-pressure isotherms showed that short chain fl- sitosteryl fatty acid esters gave smaller mean molecular areas and had decreased monolayer stability and the long chain steryl esters did not produce collapsed plateaus. All the steryl esters displayed strong condensing effects, but there was a pronounced structural dependency： medium chain esters （C8 and C 10） were less efficient than short and long chain esters. Atomic force microscopy imaging demonstrated that monolayers mixed with dipalmitoyl phosphatidylcholine （DPPC） displayed both DPPC-rich and steryl lipid-rich domains. However, the height and area differences between the two phases and the roughness and morphologic patterns were very dependent on the steryl lipid concentrations as well as the length, the degree of unsaturation and the molecular conformations of the acyl segments. These findings not only provide a better understanding of the interactions between phytosteryl hydrophobic derivatives and biomembranes, but also may be of general use for the design and engineering of phytosterol structural derivations for specific food and pharmaceutical applications.

Efficient synthesis of thiohydantoin derivatives from amino acid esters and isothiocyanates in alkaline Al_2O_3

Various amino acid esters were reacted with different isothiocyanates in alkaline Al2O3 at room temperature for 1 h affording thiohydantoins in moderate to excellent yields.