Effects of cosolvents on CO_(2) displacement of shale oil and carbon storage

Molecular dynamics method was used to establish composite wall/inorganic nanopores of three pore sizes, three shale oil systems, five CO_(2)-cosolvent systems, and pure CO_(2) system. The process of CO_(2)-cosolvent displacement of crude oil in shale nanopores and carbon storage was simulated and the influencing factors of displacement and storage were analyzed. It is shown that the attraction of the quartz wall to shale oil increases with the degree of hydroxylation. The higher the degree of quartz hydroxylation, the more difficult it is to extract the polar components of shale oil. Nanopore size also has a great impact on shale oil displacement efficiency. The larger the pore size, the higher the shale oil displacement efficiency. The closer the cosolvent molecules are to the polarity of the shale oil, the higher the mutual solubility of CO_(2) and shale oil. The more the non-polar components of shale oil, the lower the mutual solubility of CO_(2) and shale oil with highly polar cosolvent. Ethyl acetate is more effective in stripping relatively high polar shale oil, while dimethyl ether is more effective in stripping relatively low polar shale oil. Kerogen is highly adsorptive, especially to CO_(2). The CO_(2) inside the kerogen is not easy to diffuse and leak, thus allowing for a stable carbon storage. The highest CO_(2) storage rate is observed when dimethyl ether is used as a cosolvent, and the best storage stability is observed when ethyl acetate is used as a cosolvent.

Solubility and sorption of petroleum hydrocarbons in water and cosolvent systems

The solubility and sorption of oil by uncontaminated clay loam and silt loam soils were studied from water and cosolvent/water solutions using batch techniques. The data obtained from the dissolution and sorption experiments were used to evaluate the applicability of the cosolvent theory to oil as a complex mixture. Aqueous solubility and soil-water distribution coeffcients (Kd,w, L/kg) were estimated by extrapolating from cosolvent data, with a log-linear cosolvency model, to the volume fraction of cosolve...

Measurement and correlation study of silymarin solubility in supercritical carbon dioxide with and without a cosolvent using semi-empirical models and back-propagation artificial neural networks

The solubility data of compounds in supercritical fluids and the correlation between the experimental solubility data and predicted solubility data are crucial to the development of supercritical technologies. In the present work, the solubility data of silymarin(SM) in both pure supercritical carbon dioxide(SCCO2) and SCCO2 with added cosolvent was measured at temperatures ranging from 308 to 338 K and pressures from 8 to 22 MPa. The experimental data were fit with three semi-empirical density-based models(Chrastil, Bartle and Mendez-Santiago and Teja models) and a back-propagation artificial neural networks(BPANN) model. Interaction parameters for the models were obtained and the percentage of average absolute relative deviation(AARD%) in each calculation was determined. The correlation results were in good agreement with the experimental data. A comparison among the four models revealed that the experimental solubility data were more fit with the BPANN model with AARDs ranging from 1.14% to 2.15% for silymarin in pure SCCO2 and with added cosolvent. The results provide fundamental data for designing the extraction of SM or the preparation of its particle using SCCO2 techniques.

Cosolvent Effect on the Tautomerism of Ethyl Acetoacetate in Supercritical CO_2

The effect of cosolvent cyclohexane, chloroform, and acetonitrile on the keto-enol tautomeric equilibrium of ethyl acetoacetate in supercritical CO2 was studied by UV-Vis spectroscopy over the pressure range from 76 to 110 bar at 308.15 K. It was found that the equilibrium constant decreases with increasing polarity of the cosolvents.

Transdermal Delivery of Gabapentin: Effect of Cosolvent and Microemulsion on Permeation through the Rat Skin

The objective of the present study was to examine the influence of cosolvent system and micro-emulsion formulation on in-vitro skin permeation of gabapentin, furthermore, to characterize the physicochemical properties of drug-loaded oil-in-water (o/w) and water-in-oil (w/o) cremophor 40-based microemulsions in comparison to the blank counterparts. The cosolvent system prepared by homogenous mixing is composed of ethanol-water and propylene glycol-water mixture (90:10, 80:20, 70:30 v/v) respectively. The microemulsion consisted of coconut oil, water and mixture of cremophor 40 (surfactant) and ethanol (cosurfactant) and was prepared by aqueous phase titration method. Physicochemical properties of microemulsions were determined using reported procedures. Transdermal flux for gabapentin was studied in-vitro using modified Franz diffusion cells. The physicochemical properties of drug-loaded microemulsions and their blank counterparts were generally alike, however, slight variation in pH and viscosity was observed probably due to the intrinsic properties of the drug. The ethanol-water system (70:30 v/v) gave higher flux for gabapentin when compared to propylene glycol-water system (70:30 v/v). The w/o microemulsion formulations resulted in, higher flux for gabapentin when compared to o/w formulations. FTIR spectra of the untreated stratum corneum, when compared to cosolvent system and microemulsion treated stratum corneum, suggest the mechanism of permeation to be disruption of lipid bilayers and keratin denaturation of the stratum corneum. The results show that incorporation of gabapentin into microemulsions did not change the microemulsion type. The in vitro permeation data obtained from experimental work suggest that the cosolvent system (ethanol-water 70:30 v/v) and w/o microemulsion formulations respectively, can be successfully used as potential vehicles in developing transdermal therapeutic systems for gabapentin.

Investigating the effect of cosolvents on P3HT/O-IDTBR film-forming kinetics and film morphology

The morphology of active layer in bulk heterojunction(BHJ) organic solar cells is decisive to the device performance. Previous works have shown that the solvent engineering is an effective method to optimize the morphology of active layer. However, screening the proper solvent is a tedious task, and we know very little about how to select a proper solvent for a particular system, especially for polymer/nonfullerene blend systems. Here, we combined the spectroscopic analysis in various solvent mixtures during film-forming process to reveal the relationship among the cosolvent characteristics, film-forming kinetics and film morphology. In this article, P3 HT/O-IDTBR blend was selected as model system due to being facile synthesized under a large-scale. Chlorobenzene(CB) was selected as main solvent, and the cosolvents were grouped into three categories according to its boiling point(bp) compared to CB.The cosolvents with lower bp, like chloroform(CF), can facilitate a faster film-forming process, reducing the domain size but sacrificing the crystallinity of both components. For the cosolvents with higher bp,like o-dichlorobenzene(DCB) and 1,2,4-trichlorobenzene(TCB), the self-organization process of P3 HT and O-IDTBR is separated and its duration was extended, constructing highly crystalline nanointerpenetrating network. However, the cosolvents with very high bp, such as chlornaphthalene(CN),would residue in film and keep P3 HT and O-IDTBR self-organizing for longer time, leading to larger phase separation. This work systematically investigated the effect of cosolvent on the film-forming kinetics, and proposed a guideline of how to select a proper cosolvent according to the crystallinity and domain size of active layer.

Effect of Cosolvent in a Nucleophilic Substitution Reaction Using Organoclay in Triphase Catalytic System

A remarkable rate enhancement technique has been devised for a typical nucleophilic displacement reaction by using triphase catalytic materials based on tetraoctylammonium exchange forms of hectorite clay. Pseudo-first order rate constants (kobs) for the conversion of 1-bromobutane to the corresponding chloride under triphase conditions using the clay catalyst in the presence of various polar cosolvents have been observed. The results here have shown that the addition of a cosolvent increases the catalytic activity of the triphase system by several fold. In addition, the results have demonstrated that each cosolvent has a unique concentration for achieving an optimum reaction rate.

Prediction of Dermal Permeability Coefficient of Nevirapine—Effect of Cosolvents, Anionic, Nonionic and Cationic Surfactants

Transdermal drug delivery not only has contributed immensely to medical practice, but has enjoyed enormous interest in the field of cosmetic and pharmaceutical industries. Nevirapine, a non‐nucleoside reverse transcriptase inhibitor (NNRTI) is used clinically for the treatment of HIV‐ 1 infection. The aim of the present study is to investigate the influence of cosolvents (glycerol, propylene glycol, ethanol, polyethylene glycol 400) and surfactants (polysorbate 20, polysorbate 80, sodium lauryl sulfate, sodium cholate and cetrimide) on the dermal permeability coefficient of nevirapine by utilizing established and recognized mathematical model that employs partition coefficient as one of its molecular descriptors. The partition coefficient of nevirapine is determined in chloroform-water system at room temperature using the shake flask method. The results show that all the cosolvents used in this study decrease the partition coefficient of nevirapine. The same decrease in the partition coefficient of nevirapine is observed with all the surfactants investigated. The order of dermal enhancement potential of the vehicles studied based on the predicted permeability coefficient is glycerol > propylene glycol > ethanol > polyethylene glycol 400 for the cosolvents while tween 20 > tween 80 > sodium lauryl sulfate > sodium cholate > cetrimide for the surfactants. The maximum predicted flux through skin was obtained by multiplying the predicted permeability coefficient and the drug aqueous solubility. As the rate of penetration into the skin is quantitatively assessed by the use of permeability coefficient, the findings suggest that for dermal formulation of nevirapine, glycerol and tween 20 are the most preferred vehicles out of the vehicles investigated. Furthermore, the results of the correlation coefficients obtained by plotting permeability coefficient or maximum predicted flux, versus logarithm partition coefficient indicate that permeability coefficient can be a more reliable parameter to predict transdermal absorption of nevirapine than flux.

Implementation of a choline bis(trifluoromethylsulfonyl)imide aqueous electrolyte for low temperature EDLCs enabled by a cosolvent

We report a carbon/carbon capacitor based on micro/mesoporous carbon electrodes with cost-effective and eco-friendly aqueous choline bis(trifluoromethylsulfonyl)imide(Ch TFSI)electrolyte with a cosolvent enabling low-temperature operation down to-30℃.For this purpose,a Mg O-templated hierarchical carbon(MP98B)with an average mesopore diameter of 3.5 nm was prepared by pyrolysis of magnesium citrate hydrate at 900℃.To reach lower temperatures,the melting point and viscosity of the aqueous electrolyte were reduced by mixing water(W)with an organic solvent(methanol,M,or isopropanol,I)of high dielectric constant and low viscosity.5 mol kg^(-1)(5 m)Ch TFSI in an optimized volume fraction of cosolvent,M_(0.75)W_(0.25),and I_(0.75)W_(0.25),showed the highest conductivity;the higher conductivity in M_(0.75)W_(0.25)(22.8 and 3.1 m S cm^(-1) at 20 and-30℃,respectively)than in I_(0.75)W_(0.25)(8.5 and0.5 m S cm^(-1)at 20 and-30℃,respectively)is attributed to the lower viscosity of the M_(0.75)W_(0.25)solution.The electrochemical stability window(ESW)of 5 m Ch TFSI in M_(0.75)W_(0.25)and I_(0.75)W_(0.25)(1.6 V)on an MP98B electrode was determined by applying the S-method.Meanwhile,by adjusting the mass ratio of the two electrodes,a MP98B/MP98B capacitor using the 5 m electrolyte in M_(0.75)W_(0.25)could operate with a good life span up to 1.6 V while exhibiting a better charge propagation,greater specific capacitance,and higher specific energy than in I_(0.75)W_(0.25).

Micronization of Griseofulvin by Ress in Supercritical CO_2 with Cosolvent Acetone

Griseofulvin (GF) is an antifungal drug whose pharmaceutical activity can be improved by reducing particle size. In this study the rapid expansion of supercritical solution (RESS) was employed to micronize GF.Carbon dioxide with cosolvent acetone was chosen as a supercritical mixed solvent. The solubility of GF in super-critical CO2 with cosolvent acetone was measured using a dynamic apparatus at pressures between 12 and 32 MPa,temperatures at 313, 323 and 333 K and cosolvent concentration at 1.5, 3.0, 4.5 and 6.0% (by mole). The effect of pre-expansion pressure, extraction temperature, spraying distance, nozzle size and concentration of cosolvent on the precipitated particles was investigated. The results show that the mean particle size of griseofulvin precipitated by RESS was less than 1.2μm. An increase in pre-expansion pressure, extraction temperature, spraying distance and concentration of cosolvent resulted in a decrease in particle size under the operating condition studied. With the decrease of nozzle diameter the particle size reduces. The crystallinity and melting point of the original material and the processed particle by RESS were tested by X-ray diffraction (XRD) and differential scanning calorimetry (DSC).No evident modification in the crystal habit was found under the experimental conditions tested. The morphology of particles precipitated was analyzed bY scanning electron microscopy (SEM).

Aqueous Solubility Enhancement of Mirtazapine: Effect of Cosolvent and Surfactant

The poor aqueous solubility of drugs is a challenging problem faced by pharmaceutical scientists in drug formulation. Cosolvency and micellization techniques have been severally used to enhance the solubility of poorly aqueous soluble drugs. Mirtazapine, a tetracyclic antidepressant used for the treatment of moderate to severe depression and anxiety, has very poor aqueous solubility. The objective of the study was to investigate the effect of solubilizing agents (cosolvents and surfactants) on the aqueous solubility of mirtazapine while envisaging that any significant improvement in its aqueous solubility could contribute towards alleviating the withdrawal symptoms often associated with the drug. The solubility of mirtazapine was determined at room temperature in aqueous mixtures of cosolvents (propylene glycol and polyethylene glycol 400) and surfactants (polysorbate 20, polysorbate 80 and sodium lauryl sulfate). An exponential increase in mirtazapine solubility was observed when total drug solubility in water-cosolvent system was plotted against cosolvent fraction volume. Polyethylene glycol 400 gave larger solubilization capacity (σ) when compared to propylene glycol. With the surfactants, linear relationship between the total solubility of the drug in water-surfactant mixtures and surfactant concentration was noted. Sodium lauryl sulfate showed the largest solubilization power (k) when compared to the nonionic surfactants (polysorbate 20 and polysorbate 80 respectively). A linear relationship between standard free energy and partition coefficient was also observed. The result of the study shows that aqueous solubility of mirtazapine is significantly improved by cosolvency and micellization and therefore there exists the possibility of improving the withdrawal symptoms often experienced with the drug. It also suggests that large free energy is required for drugs with high partition coefficients to permeate the biological membrane.

Preparation and emission characteristics of ethanol-diesel fuel blends

The preparation of ethanol-diesel fuel blends and their emission characteristics were investigated. Results showed the absolute ethanol can dissolve in diesel fuel at an arbitrary ratio and a small quantity of water(0.2%) addition can lead to the phase separation of blends. An organic additive was synthesized and it can develop the ability of resistance to water and maintain the stability of ethanol-diesel-trace amounts of water system. The emission characteristics of 10%, 20%, and 30% ethanol-diesel fuel blends, with or without additives, were compared with those of diesel fuel in a direct injection(DI) diesel engine. The experimental results indicated that the blend of ethanol with diesel fuel significantly reduced the concentrations of smoke, hydrocarbon(HC), and carbon monoxide(CO) in exhaust gas. Using 20% ethanol-diesel fuel blend with the additive of 2% of the total volume, the optimum mixing ratio was achieved, at which the bench diesel engine testing showed a significant decrease in exhaust gas. Bosch smoke number was reduced by 55%, HC emission by 70%, and CO emission by 45%, at 13 kW/1540 r/min. However, ethanol-diesel fuel blends produced a few ppm acetaldehydes and more ethanol in exhaust gas.

Universal production of functionalized 2D nanomaterials via integrating glucose-assisted mechanochemical exfoliation and cosolvent-intensified sonication exfoliation

Two-dimensional(2D)nanomaterials have aroused immense attention in extensive applications due to their intriguing physical and chemical properties.However,there is a formidable challenge to prepare few-layered and functionalized 2D nanomaterials in an effective and universal way.Herein,we developed an integrated strategy of glucose-assisted mechanochemical exfoliation and cosolvent-intensified sonication exfoliation to effectively exfoliate and functionalize 2D materials.Taking exfoliation of boron nitride(BN)as an example,the production yield and functionalization ratio of BN nanosheets(BNNSs)reached 47.5%and 25.8 wt.%,188%and 16%higher than that of BNNSs without sonication exfoliation,respectively.The introduction of glucose not only augmented the friction force between adjacent BN layers to promote the efficiency of ball-milling-driven exfoliation supported by density functional theory calculation,but also reacted with active edges of BNNSs for functionalization.Afterwards,cosolventintensified sonication exfoliation strongly stabilized exfoliated BNNSs,obviously boosting the exfoliation yield.This proposed method is universal for preparing various 2D nanomaterials like molybdenum disulfide,tungsten disulfide,and graphene nanosheets.The thin plate structure and high functionalization ratio enabled the release of property superiorities of 2D nanomaterials.Our work offers a promising prototype to realize mass production of functionalized 2D nanomaterials.

Effects of cosolvent on formation and morphology of microspheres in precipitation polymerization of divinylbenzene in supercritical carbon dioxide

Precipitation polymerizations of divinylbenzene（DVB） in pure supercritical carbon dioxide,and parallel runs with presence of a cosolvent were carried out.The results showed that use of acetone as the cosolvent contributed greatly to the formation of the monodisperse microspheres.PDVB microspheres,with obviously higher uniformity than reported up to date,were achieved using 6-7 mL of acetone in a reactor of 50 mL with DVB concentration of 0.4 mol/L under 16 MPa,a much lower pressure than previously reported without use of cosolvent.

5-(二甲氨基)-2-甲基-5-氧戊酸甲酯在超临界二氧化碳流体染色中的应用

为提高部分分散染料在超临界二氧化碳流体(ScCO 2)中上染率,补全ScCO 2分散染料染色色谱,以5-(二甲氨基)-2-甲基-5-氧戊酸甲酯作为分散染料ScCO 2染色助溶剂,通过实验探究了染料与助溶剂质量比、染色温度、染色压力对分散染料上染率的影响,并对染色后涤纶纱线的力学性能、耐摩擦色牢度、耐日晒色牢度以及耐皂洗色牢度进行表征。结果表明:纱线得色深度明显提高,且未对纱线色相、饱和度产生明显影响;分散黄163、分散蓝60染料滤饼上染率分别为21.61%、34.25%;加入助溶剂后,分散黄163、分散蓝60的ScCO 2染色上染率分别可达57.62%、70.97%;染色纱线得色深度显著提高,染色后纱线的K/S值分别由4.5、5.9提升至12.0、12.2;最佳染色工艺为:染料与助溶剂质量比1∶20,染色温度130℃,染色压力27 MPa;加入助溶剂后染色纱线的力学性能、色牢度符合生产需求。

醚类助溶剂在超临界二氧化碳中的浊点压力及对二氧化碳-C_(16)混相压力的影响

助溶剂和CO_(2)对提高原油采收率有着协同增效作用。研究超临界CO_(2)-助溶剂体系的浊点压力和与原油的混相压力,对于CO_(2)提高原油采收率及CO_(2)埋存有着重要意义。使用改进的CO_(2)相平衡实验装置,采用根据光敏原理改进的测量方法,研究了3种助溶剂二乙二醇二甲醚(DDME)、三乙二醇二甲醚(TEDM)、四乙二醇二甲醚(TGDE)在CO_(2)中的浊点压力,考察了温度、助溶剂加量、助溶剂类型的影响;然后将这3种醚类助溶剂和常见的助溶剂乙醇对比,研究其降低CO_(2)-C_(16)混相压力的效果。结果表明,随着温度的升高,DDME、TEDM、TGDE的浊点压力逐渐升高,且呈现出低临界会溶温度(LCST)相行为。随着加量的增大,DDME、TEDM、TGDE的浊点压力逐渐升高,但增幅较小。DDME、TEDM、TGDE的极性越来越大,其与CO_(2)之间的分子间作用力逐渐减弱,导致浊点压力依次升高。在3种结构相似的醚类助溶剂中,DDME的浊点压力最低,TGDE的浊点压力最高。当DDME的质量分数为3.0%、温度为60℃时,浊点压力仅为10.14 MPa。DDME降低CO_(2)-C_(16)混相压力的效果最好,在50℃时,1.0%DDME可使混相压力的降幅达到11.25%,高于乙醇的10.62%。在温度低于50℃时,TEDM的作用效果优于乙醇,但高温下乙醇效果略优于TEDM和TGDE。DDME具有较低的浊点压力和较好的降低混相压力的能力,与CO_(2)具有较好的配伍性,也适用于地层压力较低的油藏。

有机溶剂和聚电解质提升MHET水解酶催化性能

聚对苯二甲酸乙二醇酯(PET)是一种广泛应用的塑料,但由于其难以自然降解导致严重的污染问题.PET水解酶和对苯二甲酸单乙二醇酯水解酶(MHETase)被认为是级联降解PET的关键酶,但尚未实现工业应用,本文针对MHETase开展稳定性研究以促进其工业开发.首先,选用4种不同的水溶性有机溶剂二甲基亚砜(DMSO)、N,N-二甲基甲酰胺、异丙醇和乙腈构建反应体系探寻最佳的MHETase反应条件,随后进一步研究有机溶剂和聚电解质预处理对MHETase催化活力和稳定性的影响.结果表明,当反应体系DMSO含量不高于10%时MHETase的活力几乎不受影响,其他条件下有机溶剂均会抑制MHETase活性,但这种抑制作用是可逆的,即该抑制可以通过去除有机溶剂来恢复.此外,低浓度的有机溶剂预处理能够提高MHETase的催化活力,且DMSO预处理能够提升MHETase的储存稳定性及热稳定性,MHETase在4℃下10%DMSO中储存96 h后的活力为原有活力的113%,在30℃下10%DMSO中孵育6 h后也能保持原有活力的103%.研究发现,MHETase活力可以通过阴、阳离子聚电解质孵育来提升,与等量阴、阳离子聚电解质共孵育的MHETase在4℃下10%DMSO中储存144 h也能保持118%的活力,但与DMSO预处理相比,聚电解质预处理对MHETase活力提升程度有限.本研究系统考察了有机溶剂和聚电解质对MHETase催化性能的影响,并指出DMSO和聚电解质的预处理有助于MHETase在常温下的储存和应用,为MHETase的工业应用提供了更多参考.

超临界二氧化碳流体中SCFX-AYRL染料的溶解性研究

染料在超临界二氧化碳流体(SCF-CO_(2))中的良好溶解性是超临界无水染色技术应用的前提和基础。采用研制的超临界流体溶解度测试装置,研究了活性分散红SCFX-AYRL专用染料在SCF-CO_(2)中的溶解性,并分别从流体处理时间、温度、系统压力和助溶剂应用方面对该专用染料溶解性的影响进行了探讨。研究表明当系统压力为20 MPa、温度为80~130℃时,SCF-CO_(2)中该染料在30~60 min可达到溶解平衡,在一定范围内升高流体温度和系统压力可提高专用染料的溶解性;加入助溶剂可显著改善染料的溶解行为,提高其溶解度及溶解速率,降低温度、压力等系统因素的影响;Chrastil经验模型可实现对SCF-CO_(2)和SCF-CO_(2)/助溶剂体系中该专用染料溶解行为的良好关联和预报。

一种兽用地美硝唑预混剂的制备及稳定性研究

以地美硝唑为主成分原料,以聚乙二醇6000、倍他环糊精作为主成分的助溶剂,地美硝唑和辅料经过过筛、混合后进行粉碎制得地美硝唑预混剂。该配方的组合为:质量比M(地美硝唑):M(倍他环糊精):M(聚乙二醇6000)=2:2:6。研究表明地美硝唑预混剂的溶解度良好,溶解度可达8.0%;按地美硝唑预混剂的质量标准要求检测,合格。该配方组合可以同时实现药物的饮水和拌料给药。在密闭条件下保存,长期试验2年,产品的性状和外观几乎没有改变;地美硝唑含量从初始的100.1%下降至97.5%,有效成分含量下降幅度未超过地美硝唑标示量百分含量的10%。产品质量稳定,符合兽药典的要求。地美硝唑预混剂的配方合理、生产操作简单,产品24个月质量稳定,有效期可暂定为24个月。

高效液相-纳克级激光计数检测器联用法测定注射用兰索拉唑中葡甲胺的含量

目的建立高效液相-纳克级(水凝粒子)激光计数检测器(HPLC-NQAD)联用法测定注射用兰索拉唑中助溶剂辅料葡甲胺的含量。方法采用HPLC-NQAD联用,色谱柱使用CAPCELL PAK CR 1∶4(2.0 mm×150 mm,5μm);以流动相(A)(5 mmol·L^(-1)甲酸铵-2%乙腈)和流动相(B)(50 mmol·L^(-1)甲酸铵-50%乙腈)梯度洗脱;流速0.3 mL·min^(-1);柱温40℃;进样量5μL;NQAD参数设定:蒸发温度35℃,雾化温度30℃,氮气压力30 psi。结果供试品中的葡甲胺和其他成分能够良好分离,在1.0~100.0μg·mL^(-1)范围内,葡甲胺的浓度与峰面积呈良好线性关系,相关系数r=0.9998,平均回收率为99.96%,精密度RSD为1.01%。结论该方法结果准确,重复性好,可实现注射用兰索拉唑中无紫外吸收辅料葡甲胺的高灵敏检测。