Sulphoxide Solution Research Articles

Morphology transformation of thermosensitive metronidazol by spray freeze-drying

Spray freeze-drying (SFD) is an effective method for reducing the size of thermosensitive organic substances that are sparingly soluble in water. Despite the advantages of the method, its use has not yet become widespread. We aimed at studying SFD technique for metronidazole as a heat-sensitive active pharmaceutical ingredient for reducing its particle size and investigated the morphological and physical parameters of the modified drug.The obtained particles were crystalline in all cases and their sizes were two and one order of magnitude smaller using water or dimethyl sulphoxide solutions, respectively, as compared to the initial reference metronidazole. The particle size varied depending on the experimental parameters (atomization pressure, peristaltic pump speed), although, the operating parameters had a smaller effect on the size of the materials than the applied concentration of starting solution, regardless of the solvent. The as-prepared samples had a microcrystalline structure that is retained for a long time.

Studies of molar refraction and polarizability constant of 6-(4-chlorophenyl)-1,2,3,4-tetrahydro-2, 4-dioxopyrimidine-5-carbonitrile in 60% DMSO in the temperature range 298 to 313 K

Objectives: The main purpose of this study is to investigate the impact of 6-(4-chlorophenyl)-1, 2, 3, 4-tetrahydro-2, 4-dioxopyrimidine-5-carbonitrile in binary solution at different concentrations and valuable information on electronic polarizability and molecular interactions in the solution. Methods: 6-(4-chlorophenyl)-1, 2, 3, 4-tetrahydro-2, 4-dioxopyrimidine-5-carbonitrile was synthesized and purified by recrystallization technique in laboratory(1). DMSO used is of analytical reagent grade (AR) of minimum assay of 99.9%. Stock solutions of 0.02 (mol L-1) of compound were prepared by dissolving calculated amounts in 60% dimethyl sulphoxide solution. Solutions in various concentration ranges from 0.002 to 0.010(mol L-1). The pycknometer was calibrated by measuring the densities of triple distilled water. The densities of distilled organic liquids like acetone, toluene and carbon tetrachloride were evaluated with respect to density of water. Refractive index were measured by Abbe’s Refractometer (AR-56, COSLAB) having range 1.3000 to 1.7100. The desired temperature was maintained by circulating water through refractometer. Findings: In the present work we found that density, refractive index, molar refraction and polarizability constant increases the increase in concentration due to decrease in angle of refraction or increase in angle of incidence. The decrease in density with increase in temperature is due to increase in molar volume of solvent. However, the decrease in refractive index is due to the fact that the solute-solute and solute-solvent interactions weaken with increase in temperature. This can be correlated that change in these properties changes the intermolecular attraction between solute and solvent. With increase in temperature the interaction between solute and solvent weakens and hence molar refraction and polarizability decreases. Novelty: The work incorporated with the study of molar refraction and molar polarizability of 6-(4-chlorophenyl)-1, 2, 3, 4-tetrahydro-2, 4-dioxopyrimidine-5-carbonitrilehas been not studied until now. So we wish to present the systematic measurement of refractive index of 6-(4-chlorophenyl)-1, 2, 3, 4-tetrahydro-2, 4-dioxopyrimidine-5-carbonitrile in 60% DMSO in the temperature range 298 to 313 K at different concentration. From refractive index we have calculated molar refraction and molar polarizability which has provided important information regarding interactions between solute and solvent. Keywords: 6-(4-chlorophenyl)-1; 2; 3; 4-tetrahydro-2; 4-dioxopyrimidine-5-carbonitrile; refractive index; molar refraction; molar polarizability

ДОСЛІДЖЕННЯ ПЕРЕРОБКИ ПРОДУКТІВ УТИЛІЗАЦІЇ ТВЕРДОГО РАКЕТНОГО ПАЛИВА

У сучасних умовах для України актуальним екологічним питанням э утилізація споряджених корпусів двигунів (СКД) із закінченим терміном зберігання. В ході утилізації утворюється полімерна матриця (ПМ) з середнім розміром фрагментів 2 - 15 мм, до складу якої входить до 30% ціклотетраметілентетранітраміна (нітраміна), виробництво якого відсутнє в Україні, його можливо регенерувати із застосуванням диметилсульфоксида (ДМСО). Метою даної роботи є встановлення закономірностей вилучення нітраміну з ПМ за допомогою ДМСО в лабораторних умовах зі зміною такого параметра як масовий модуль (відношення ДМСО: ПМ) в залежності від вологості ПМ. На основі експериментальних даних встановлено залежності масового модуля (відношення ДМСО: ПМ) на ступінь вилучення нітраміна за допомогою ДМСО з ПМ. Найкращим масовим модулем (ставленням ДМСО: ПМ) можна вважати діапазон 2 - 3, що дозволяє досягти ступеня вилучення нітраміни 71,9% (при вологості ПМ 3%). Ідетіфікаціі вилученного з ПМ нітраміна підтверджена ІЧ-спектром і ДТА.

Structure and chain conformation characteristics of high acyl gellan gum polysaccharide in DMSO with sodium nitrate

High acyl gellan gums have been widely considered using as gelling biopolymers in colloidal products although their structure and chain conformation characteristics have been poorly understood. Five fractions of high acyl gellan gum (HG) with a molecular weight (Mw) ranging from 4.2 × 105 to 10.1 × 105, obtained by ultrasonic depolymerization from a native gellan, have been used to determine their molecular parameters and conformation characteristics in the good solvent of 50 mM NaNO3 dimethyl sulphoxide solution by using capillary viscometry and laser light scattering. The influence of ultrasound on the chemical structure and Mw of HG is investigated by GPC, FT-IR and NMR. The chain architectures of HG fractions are confirmed to be very similar to that of the native one without either deacylation or deglycerylation. Mark−Houwink equation and the relationship between radius of gyration (Rg) and Mw are established to be [η] = 1.16 × 10−3Mw0.67 (dl/g) and Rg = 2.06 × 10−2Mw0.61 (nm) for HG with a ratio of geometric to hydrodynamic radius (Rh) of 1.67 that is independent of the Mw of HG. In term of Zimm model, a relationship among these molecular parameters is founded as [η]≈4NARg2Rh/Mw. On the basis of unperturbed chain models, the conformation parameters of HG are also calculated and compared. The results indicate that HG macromolecules with an estimate of about 9 nm for persistence length Lp take the conformation of relatively extended semi-flexible chains in solution.

Red/blue shifting hydrogen bonds in acetonitrile-dimethyl sulphoxide solutions: FTIR and theoretical studies

FTIR spectra of neat acetonitrile (AN), dimethyl sulphoxide (DMSO) and their binary solutions at various mole fractions have been recorded at room temperature. Theoretical calculations have also been carried out on acetonitrile (monomer, dimer), dimethyl sulphoxide (monomer, dimer) and AN – DMSO complex molecules. 1:2 (AN:DMSO) and 2:1 complexation through the red shifting (AN)C−H⋯O=S(DMSO) and blue shifting (DMSO)C−H⋯N≡C(AN) hydrogen bonds has been identified. The experimental and theoretical studies favour the presence of both the monomer and dimer in liquid AN, but only closed dimers in DMSO. The dipole-dipole interactions existed in AN and DMSO dimers disappear in the complex molecules. Partial π bond between S and O atoms, and three lone pair of electrons on oxygen atom of DMSO have been noticed theoretically.

A selective chemosensor for fluoride ion and its interaction with Calf Thymus DNA

The amido-Schiff base 1 (N1, N3-bis (2-nitrobenzylidene)benzene-1,3-dicabohydrazide) containing a CONH group and CHN linkage has been synthesized by the condensation between isophthalic acid dihydrazide and o-nitrobenzaldehyde. This molecule can act as a fluoride ion sensor with high selectivity and sensitivity. Presence of nitro group in the phenyl ring may be responsible for the detection of fluoride ion visually with a dramatic color change from colorless to deep red in aqueous dimethyl sulphoxide solution. This Schiff base can be used as test kit for sensing of fluoride ion in the solid state. Compound 1 can detect fluoride also in commercially available toothpaste. As the compound has adequate solubility in DMSO–water mixture (7:93, v/v) and having some hydrogen bond donor and acceptor centers, we have investigated its nature of binding with Calf Thymus-DNA (CT-DNA) using theoretical molecular modelling and other experimental methods like UV–vis spectroscopy, circular dichroic and thermal melting studies. Thermodynamic parameters have been obtained using the well known Van't Hoff's equation. From both theoretical and experimental findings it has been observed that it can interact effectively with CT-DNA with binding energy −7.55kcal/mol to −7.50kcal/mol.

A Silver–Organic Frameworks Based on Flexible-Aromatic Dicarboxylate and Bipyridinyl Skeletons Coligand: Crystal Structure and Luminescence Property

Reaction between silver salt and conjugational N-hetrocyclic carboxylic acid with the presence of bipyridyl skeletons auxiliary ligand afforded a d10 metal polymer namely [(ddpp)Ag(bipy) (1)] (ddpp = 2, 5-di(2′,4′-dicarboxylphenyl)pyridine, bipy = 4,4′-bipyridine). It was characterized by elements analysis, infrared spectroscopy, single crystal X-ray diffraction and thermogravimetry studying. For the polymer 1, silver centers are three coordinated geometry with an ON2 donor set provided by ddpp and bipy. The polymer 1 is built from 1-D alternative/zig-zag chain, as the secondary building unit, and further stacks via hydrogen bonds which formed between two isophthalic moieties of ddpp ligands and weak interactions to generate a two-dimensional, 2D supramolecular layer. Moreover, the polymer 1 displays thermal stability in solid state and the luminescence behaviour is also investigated in a dimethyl sulphoxide solution at ambient temperature, and it also can be applied in design of sensors to detect of trace aluminum, zinc and calcium ion.

Acoustical Studies of some Chalcones in DMF and DMSO Solutions

This work reports densities, speeds of sound, and isentropic compressibility of the solutions of some synthesized chalcones in N,N-dimethylformamide and dimethyl sulphoxide solutions of various concentrations at 308.15 K with a view to understand molecular interactions in these solutions.

Acoustical Studies of some Chalcones in DMF and DMSO Solutions

This work reports densities, speeds of sound, and isentropic compressibility of the solutions of some synthesized chalcones in N,N-dimethylformamide and dimethyl sulphoxide solutions of various concentrations at 308.15 K with a view to understand molecular interactions in these solutions.

Colorimetric detection of in situ metal acetates and fluorides by a bipyridyl-linked Schiff base.

Here, we present a new bipyridyl moiety linked Schiff base (bipy-1) that is well characterized using spectroscopic techniques. Colorimetric and UV-vis titrations were used to study the photophysical properties of bipy-1 in the presence of various tetrabutyl ammonium salt of anions and metal salts containing different counter cations. bipy-1 showed selective recognition of dimethyl sulphoxide solution of tetrabutyl ammonium salt of F(-) ion accompanied with a UV-vis band at 529 nm and interesting binding of aqueous Co, Ni, and Cu acetates/fluorides, as confirmed by distinct color changes from fluorescent green to pink or orange and a strong band around 480-510 nm in the UV-vis spectrum. However, in the presence of Co, Ni, and Cu countercations, any form of metal acetate/fluorides was found to be able to respond to similar color changes from fluorescent green to pink or orange, showing a band around 480-510 nm. This type of output clearly indicates that the in situ formation of Co, Ni, and Cu acetates/fluorides also coordinates with bipyridyl nitrogen atoms.

Optical nonlinearities in non-peripherally substituted pyridyloxy phthalocyanines: a combined effect of symmetry, ring-strain and demetallation

The optical nonlinearities of six non-peripherally-substituted pyridyloxy phthalocyanines have been studied at 532 nm using a nanosecond Z-scan technique in a dimethyl sulphoxide solution. Ring-strain effects and the absence of a metal center were found to greatly reduce the inherent high nonlinearities expected of some of these phthalocyanine complexes. Of the six molecules investigated, 1(4),8(11),15(18),22(25)-tetrakis-(2-pyridyloxy)phthalocyaninato lead(II) 3, 1(4),8(11),15(18),22(25)-tetrakis-(2-pyridyloxy)phthalocyanine 5, and 1(4),8(11),15(18),22(25)-tetrakis-(4-pyridyloxy)phthalocyanine 6 were found to exhibit negligible nonlinear optical behavior, due to either the absence of asymmetry or central metal and/or the presence of a ring-strain effect. A two-photon absorption process was found to be the major contributor to the observed reverse saturable absorption (RSA) in 1(4),8(11),15(18),22(25)-tetrakis-(4-pyridyloxy)phthalocyaninato lead(II) 4, 1(4)-mono-(2-pyridyloxy)phthalocyaninato lead(II) 7, and 1(4)-mono-(4-pyridyloxy)phthalocyaninato lead(II) 8, with large two-photon absorption cross-section, high hyperpolarizability and high third-order susceptibility values in the range of 4.53 × 10(-43)-5.33 × 10(-42) cm(4) s per photon, 1.61 × 10(-28)-1.89 × 10(-27) esu and 9.73 × 10(-12)-7.05 × 10(-11) esu respectively.

Nonlinear optical behavior of metal octaphenoxy phthalocyanines: effect of distortion caused by the central metal

In this work, we investigated the nonlinear optical absorption properties of chloroaluminum, chlorogallium, chloroindium, zinc and lead octaphenoxy phthalocyanines in a dimethyl sulphoxide solution using 5 ns pulses at 532 nm. Using the Z-scan technique, the nonlinear optical properties and the excited state absorption cross-sections were determined by fitting the Z-scan data. The k value was the highest for Pb derivative at 211, making it the best nonlinear optical material. In terms of hyperpolarizability, Pb derivative (containing a larger central metal) also gave the largest value followed by aluminum derivative (containing a small central metal). The distortion of the ring caused by the central metal is used to explain the hyperpolarizability values. Large nonlinear absorption coefficient values, β eff , in the range of 3.558–4.763 × 10-9 cm.W-1 and low saturation fluence values, F sat between 21.5–38.5 mJ.cm-2, were obtained for these samples.

Chain extended vinyl aniline modified cyclohexanone formaldehyde resin

PurposeThe purpose of this paper was as follows. The in situ chemical oxidation (ICO) of vinyl aniline modified cyclohexanone formaldehyde resin (CFVAnR) in the presence of potassium persulphate salt (K2S2O8) was accomplished in dimethyl sulphoxide (DMSO) solutions at 35°C and 70°C. The chemical composition and structure of the oxidized CFVAnR were characterised by nuclear magnetic resonance (1H‐NMR) spectroscopy, Fourier transform infrared (FT‐IR) spectroscopy, DSC, TGA and SEM.Design/methodology/approachThe reactive vinyl and amine groups of the cyclohexanone formaldehyde resin were reacted in the presence of potassium persulphate. CFVAn resin was dissolved in DMSO inside a round bottom flask immersed in a water bath thermostated at reaction temperature of 35°C and 70°C, respectively. Solution of K2S2O8 was prepared in DMSO and this was added into the resin solution.FindingsIt was shown that the vinyl groups in the resin were reacted easily with persulphate salt to obtain chain extended CFVAnR (CECFVAnR). The oxidised 4‐vinyl aniline modified cyclohexanone‐formaldehyde resin has solublity in organic solvents.Research limitations/implicationsThe reaction mixture must be stirred continuously. Temperature should be controlled to prevent the thermal polymerisation of vinyl group and higher branching of amino groups. The persulphate ion (S2O82−) has a standard oxidation potential, but when activated by heat (40‐60°C). Furthermore, sulphate radical can react with water or hydroxide to produce hydroxyl radical (−OH). When persulphate is used for in situ chemical oxidation (ISCO) application at relatively low temperatures (e.g. <20°C), the oxidation reactions are usually less aggressive due to a slow generation rate of SO4−.Practical implicationsThis study provides technical information for the synthesis of chain extended resins. The modified resins contain vinyl groups. The chemical radical system has been used to polymerise these vinyl groups and resins with much higher molecular weight might be produced. The resins may also promote the adhesive strength of a coating and corrosion inhibition to metal surfaces of a coating.Social implicationsThis resin will be used for the preparation of AB‐ and ABA‐type block copolymers. These block copolymers may exhibit different properties due to incorporation of ketonic resins into the block copolymer structure.Originality/valueChain extended CFVAnR (CECFVAnR) was synthesised by one step reduction‐oxidation reaction, at 35°C (CECFVAnR1) and 70°C (CECFVAnR2) in the presence of potassium persulphate salt. These soluble resins may overcome difficulties in the applications of polymers and open new application areas. Therefore, the chain extended vinyl aniline modified resin may find a number of new application areas as well as existing UV curable resin and polymer applications.

Electrospun polyacrylonitrile nanofibers modified by quaternary ammonium salts

AbstractElectrospinning from a capillary is one of the methods for the production of nanofibers. The specific properties of such fibers result first of all from their large specific surface and the high porosity of the fiber mat. This article presents a process for producing functional nanofibers with antimicrobiological properties by electrospinning from polyacrylonitrile/dimethyl sulphoxide solution containing a bioactive agent based on quaternary ammonium salts (N, N, n, n,‐didecyl‐N,N‐dimethylammonium chloride, Bis‐(3‐aminopropyl)‐dodecylamine) and 2‐propanol. The structure of the nanofibers obtained and their antimicrobial activity are investigated. A 5 wt % addition of bioactive preparation to the polymer solution (concentration of active substance in solution about 1.5 wt %) makes it possible to obtain fibers showing good bactericidal properties. After 6 h in contact with these fibers, Escherichia coli are eliminated to a level of 99.84% and Staphylococcus aureus to 99.99%. The IR spectrophotometric measurements do not indicate a residue of solvent in the bioactive nanofibers and show an increase in content of CH and CH2 groups in relation to the pure nanofibers, which is connected with the presence of the biocide. Their degree of crystallinity determined by the X‐ray scattering method is 44.4%. The nanofibers obtained can be designed for medical and filtration applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Cyclic voltammetry study of the electrocatalytic reduction of sevoflurane by a cobalt(III) Schiff base complex in the presence of oxygen

The electrocatalytic reduction of sevoflurane has been carried out at a platinum electrode using cyclic voltammetry. It was found that the sevoflurane molecule is non-electroactive in the potential region between 0.5 and −2.3 V vs. Ag/AgCl (satd.) electrode in dimethyl sulphoxide (DMSO) solution. However, the results show that, in a mixture with oxygen, cobalt(III) Schiff base complex (CoLOAC), and sevoflurane, an irreversible peak appears at about −1.77 V vs. Ag/AgCl (satd) electrode. It was observed that the peak height increases linearly with sevoflurane concentration up to 7.5 mM. The detection limit is estimated to be 0.5 mM.

Scratch-Resistant, Highly Conductive, and High-Strength Carbon Nanotube-Based Composite Yarns

High-strength and conductive carbon nanotube (CNT) yarns are very attractive in many potential applications. However, there is a difficulty when simultaneously enhancing the strength and conductivity of CNT yarns. Adding some polymers into CNT yarns to enhance their strength will decrease their conductivity, while treating them in acid or coating them with metal nanoparticles to enhance their conductivity will reduce their strength. To overcome this difficulty, here we report a method to make high-strength and highly conductive CNT-based composite yarns by using a continuous superaligned CNT (SACNT) yarn as a conductive framework and then inserting polyvinyl alcohol (PVA) into the intertube spaces of the framework through PVA/dimethyl sulphoxide solution to enhance the strength of yarns. The as-produced CNT/PVA composite yarns possess very high tensile strengths up to 2.0 GPa and Young's moduli more than 120 GPa, much higher than those of the CNT/PVA yarns reported. The electric conductivity of as-produced composite yarns is as high as 9.2 × 10(4) S/m, comparable to HNO(3)-treated or Au nanoparticle-coated CNT yarns. These composite yarns are flexible, lightweight, scratch-resistant, very stable in the lab environment, and resistant to extremely humid ambient and as a result can be woven into high-strength and heatable fabrics, showing potential applications in flexible heaters, bullet-proof vests, radiation protection suits, and spacesuits.

ChemInform Abstract: Ring Transformations of 5-Chloro-1,2,3-thiadiazole-4-carbaldehyde with Amines, Hydrazines and Hydroxylamine.

5-Chloro-1,2,3-thiadiazole-4-carbaldehyde, prepared in four steps from 1,3-dichloroacetone, reacts with alkyl- and aryl-amines in alcohol solution to give 1,2,3-triazole-4-thiocarboxamides 9a–f. Similarly, hydrazine and N-aminomorpholine furnish the 1,2,3-triazole-4-thiohydrazides 9g and 9h, whereas phenylhydrazine and hydroxylamine yield unrearranged products 8i and 8j. These, however, are transformed into 1,2,3-triazole-4-carboxylic acids 14i and 14j upon storage in dimethyl sulphoxide solution. The mechanism of the rearrangement is discussed.

Properties of Polymer Electrolyte Membranes Based on Poly(Aryl Ether Benzimidazole) and Sulphonated Poly(Aryl Ether Benzimidazole) for High Temperature PEMFCs

AbstractMembranes based on poly[2,2′‐(p‐oxydiphenylene)‐5,5′‐bibenzimidazole] (OPBI) and their sulphonated derivatives (SOPBI) were prepared and first investigated for high temperature proton exchange membrane fuel cells. OPBI and SOPBI membranes with good chemical stability were prepared by casting from their dimethyl sulphoxide (DMSO) solution and then impregnated in phosphoric acid baths to obtain H3PO4 (PA)‐doped membranes. The properties of PA‐doped OPBI membranes, including phosphoric acid uptake, swelling ratio, mechanical properties and thermal properties, were fully investigated and compared with PA‐doped SOPBI membranes. The fuel cell performances of PA‐doped OPBI and SOPBI membranes at different temperatures were first evaluated. When doped in different concentrations of H3PO4 solution, OPBI membranes adsorb more acid than SOPBI membranes. SOPBI membranes exhibit obviously lower swelling ratio in thickness direction than that of OPBI membranes. With an acid uptake of ∼110 wt.‐%, corresponding doping level around 5, PA‐doped OPBI and SOPBI membranes keep reasonably high tensile strength. PA‐doped OPBI membranes exhibit peak power density of 0.78 W cm–2 at 170 °C and 0.25 MPa. With the same acid uptake, PA‐doped SOPBI membranes displayed similar fuel cell performance to that of PA‐doped OPBI membranes.

Synthesis and Characterisation of Sulphonated Poly(arylene sulphone) Terpolymers with Triphenylphosphine Oxide Moieties for Proton Exchange Membrane Fuel Cells

AbstractFor application in fuel cells, a series of sulphonated poly(phenylene sulphone) terpolymers with triphenylphosphine oxide moieties as constitutional units in the polymer backbone have been prepared. The synthesis of the terpolymers represents a two‐step process including: (i) an aromatic nucleophilic substitution polycondensation of three difluoro monomers with varying ratios, i.e. 3,3′‐disulphonate‐4,4′‐difluorodiphenylsulphone, 4,4′‐difluorodiphenylsulphone and bis(4‐fluorophenyl)phenyl phosphine oxide (BFPPO), with 4,4′‐thiobisbenzenethiol yielding sulphonated poly(phenylene sulphide) terpolymers (sPPSPO) and (ii) their following oxidation with hydrogen peroxide in acidic solution to yield sulphonated poly(phenylene sulphone) terpolymers (sPPSO2PO). The structures and molecular compositions were confirmed by 1H and 13C NMR spectroscopy. The ion exchange capacity (IEC) was adjusted at will choosing the appropriate ratio of sulphonated and unsulphonated monomers. Terpolymers with 1.72 ≤ IEC ≤ 2.32 have been obtained. Sulphonated poly(arylene) ionomers containing only sulphone (–SO2–) linkages and phosphine oxide (–PO–) units rather than ether or sulphide in the backbone reveal a high thermal and oxidative stability. Membranes were cast either from dimethylformamide (DMF) or from dimethyl sulphoxide (DMSO) solutions. For all terpolymers some general characteristic trends were observed, such as an increase of the proton conductivity with increasing IEC, water uptake and temperature. The series of sPPSO2PO membranes offered high conductivities at high humidification, however, their performance strongly depends on the relative humidity.The mechanical properties of sulphonated poly(phenylene sulphone)s have been considerably improved by means of terpolymerisation with phenylene oxide moieties. Even under high humidification the terpolymers form clear, flexible membranes the stress at break of some membranes exceeds that of Nafion® under the same conditions by 40%.

Investigation on an evanescent wave fiber-optic absorption sensor based on fiber loop cavity ring-down spectroscopy

An improved ring-down measurement principle for optical waveguides is presented. Fiber loop ring-down spectroscopy allows for measurement of minute optical losses in high-finesse fiber-optic cavities and immunity to the fluctuation of laser source. The evanescent wave absorption losses dependent on the absorption and the refractive index of ambient solution have been theoretically analyzed. The complex refractive index is introduced into our model and extinction coefficient can be calculated accurately through finite element analysis by setting the boundaries of the fiber and the ambient conditions. Using this method, the refractive index of environment can be taken into consideration. Our principle is validated by the highly-sensitive measurement of evanescent wave absorption loss. By chemically processing the surface of sensing segment along an extending ring-down cavity, the concentration of small volume Diethyl Sulphoxide solution where the etched fiber immersed into has been successfully measured and discussed.