Determination of sub-micromolar amounts of sulfide by standard free anodic stripping voltammetry and anodic stripping voltammetric titration

A novel electrochemical methods namely standard free anodic stripping voltammetry and anodic stripping voltammetric titration are proposed for determination of dissolved sulfide concentration. 2Ag⁺ + S²⁻ → Ag₂S reaction is used to provide the information. The anodic stripping voltammetric response of unreacted silver-ions at the glassy carbon electrode is used as analytical signal. Results reliability and accuracy are confirmed by analysis of model solutions, spiked natural and tap waters and recovery study, with a recovery of 100 ± 5% (n = 7) obtained. The approaches show the detection limit (3σ_blank) of 2-5 × 10⁻¹⁰ mol L⁻¹ and the relative standard deviation of 2-5% for repeated measurements.     

Polymeric ionic liquid as a dynamic coating additive for separation of basic proteins by capillary electrophoresis

A simple and economical capillary electrophoresis method has been developed for the analysis of four model basic proteins by employing a polymeric ionic liquid (PIL), poly(1-vinyl-3-butylimidazolium) bromide, as the dynamic coating additive. When a small amount of PIL was present in the background electrolyte, a cationic coating on the inner surface of fused-silica capillary was established. These PIL modified capillaries not only generated a stable reversed electroosmotic flow, but also effectively eliminated the wall adsorption of proteins. Several important parameters such as the PIL concentration in the background electrolyte, pH values and concentrations of the background electrolyte were optimized to improve the separation of basic proteins. Consequently, under the optimum conditions, a satisfied separation of basic proteins with peak efficiencies ranging from 247,000 to 540,000 (plates m⁻¹) had been accomplished within 11 min. The run-to-run RSDs (n = 3) of the migration times for the four basic proteins were all less than 0.37%.     

Selective and specific detection of sulfate-reducing bacteria using potentiometric stripping analysis

A fast, sensitive and reliable potentiometric stripping analysis (PSA) is described for the selective detection of the marine pathogenic sulfate-reducing bacterium (SRB), Desulforibrio caledoiensis. The chemical and electrochemical parameters that exert influence on the deposition and stripping of lead ion, such as deposition potential, deposition time and pH value were carefully studied. The concentration of SRB was determined in acetate buffer solution (pH 5.2) under the optimized condition (deposition potential of −1.3 V, deposition time of 250 s, ionic strength of 0.2 mol L⁻¹ and oxidant mercury (II) concentration of 40 mg L⁻¹). A linear relationship between the stripping response and the logarithm of the bacterial concentration was observed in the range of 2.3 × 10 to 2.3 × 10⁷ cfu mL⁻¹. In addition, the potentiometric stripping technique gave a distinct response to the SRB, but had no obvious response to Escherichia coli. The measurement system has a potential for further applications and provides a facile and sample method for detection of pathogenic bacteria.     

The versatility of salicylaldehyde thiosemicarbazone in the determination of copper in blood using adsorptive stripping voltammetry

The adsorptive cathodic stripping voltammetry technique (AdCSV) is used to determine copper(II) using salicylaldehyde thiosemicarbazone (N, S- donor) as a complexing agent on hanging mercury drop electrode at pH 9.3. Variable factors affecting the response, i.e. the concentration of ligand, pH, adsorption potential and adsorption time are assessed and optimized. The adsorbed complex of copper(II) and salicylaldehyde thiosemicarbazone gives a well defined cathodic stripping peak current at −0.35 V, which has been used for the determination of copper in the concentration range of 7.85 × 10⁻⁹ to 8.00 × 10⁻⁶ M with accumulation time of 360 s at −0.1 V versus Ag/AgCl. This technique has been applied for the determination of copper in various digested samples of whole blood at trace levels.     

Application of SiO2-poly(dimethylsiloxane) hybrid material in the fabrication of amperometric biosensor

A highly sensitive adsorptive stripping voltammetric protocol for measuring trace beryllium, in which the preconcentration is achieved by adsorption of the beryllium-arsenazo-I complex at a preplated mercury-coated carbon-fiber electrode, is described. Optimal conditions were found to be a 0.05 M ammonium buffer (pH 9.7) containing 5 μM arsenazo-I, an accumulation potential of 0.0 V (versus Ag/AgCl) and a square-wave voltammetric scan. The new procedure obviates the need for renewable mercury-drop electrodes used in early stripping protocols for beryllium. A linear response is observed over the 10-60 μg l⁻¹ concentration range (90 s accumulation), along with a detection limit of 0.25 μg l⁻¹ beryllium (10 min accumulation). A 15-s electrochemical cleaning enables the same mercury film to be used for a prolonged operation. High stability is thus indicated from the reproducible response of a 100 μg l⁻¹ beryllium solution (n = 60; RSD = 3.3%) over a 2.5-h operation. Applicability to a seawater sample is illustrated. The attractive behavior of the new sensor holds great promise for on-site environmental and industrial monitoring of beryllium. Preliminary data in this direction using mercury-coated screen-printed electrodes are encouraging.     

Determination of traces of cobalt in the presence of nioxime and cetyltrimethylammonium bromide by adsorptive stripping voltammetry

A sensitive method of Co(II) determination by adsorptive stripping voltammetry is presented. The method exploits the enhancement of cobalt peak current observed in the system Co(II)-nioxime-cetyltrimethylammonium bromide-piperazine-N,N′-bis(2-ethanesulfonic acid). The calibration plot for an accumulation time of 60 s is linear from 5 × 10⁻¹¹ to 3 × 10⁻⁹ mol L⁻¹. The relative standard deviation is 3.8% for Co(II) determination at concentration 1 × 10⁻⁹ mol L⁻¹. The detection limit is 1.7 × 10⁻¹¹ mol L⁻¹. The validation of the method is performed by the analyses of certified reference materials and comparing the result of Co(II) determination in river water sample by the proposed method with those obtained by ET AAS. The main advantage of this new system is the micro-trace Co(II) determination by adsorptive stripping voltammetry, as compared to those described before, a low concentration of the supporting electrolyte used, and so commercially available reagents without additional purification can be used.     

Near-infrared fluorimetric determination of nucleic acids by shifting the ion-association equilibrium between tetracarboxy aluminum phthalocyanine and tetra-N-hexadecylpyridiniumyl porphyrin

A new method was developed for determination of micro amounts of nucleic acids based on near-infrared (near-IR) fluorescence recovery, employing a two-reagent system which is composed of an anionic tetracarboxy aluminum phthalocyanine (AlC₄Pc) and a cationic tetra-N-hexadecylpyridiniumyl porphyrin (TC₁₆PyP). The fluorescence of the AlC₄Pc, with the maximum emission wavelength at 701 nm, could be quenched by TC₁₆PyP at its proper concentration, but recovered by adding nucleic acids. Under optimal conditions, the recovered fluorescence is proportional to the concentration of nucleic acids. The calibration graphs are linear over the range of 1-200 ng mL⁻¹ for fish sperm DNA (FS DNA) and 2-400 ng mL⁻¹ for calf thymus DNA (CT DNA). The corresponding detection limits are 0.59 ng mL⁻¹ for FS DNA and 0.82 ng mL⁻¹ for CT DNA, respectively. Four synthetic and three real nucleic acid samples were determined with satisfactory results.     

Voltammetric determination of Imatinib (Gleevec) and its main metabolite using square-wave and adsorptive stripping square-wave techniques in urine samples

The voltammetric behaviour of Imatinib (STI 571) and its main metabolite (N-demethylated piperazine derivative) were studied by square-wave techniques, resulting in to two methods for their determination in aqueous and urine samples at pH 2. The application of the square-wave (SW) without the adsorptive accumulation and voltammetric stripping (AdSV) exhibit a peak at a reduction potential of −0.70 V for an accumulation potential of −0.45 V. The sensitivity was higher for the stripping technique because a signal four times higher than that provided by the square-wave method without the previous accumulation was obtained. Due to the fact that Imatinib and its metabolite show the same voltammetric reduction process, some experiments were performed in order to compare the voltammetric response of Imatinib and its main metabolite in a similar ratio than that of the therapeutic concentration. The calibration curve for Imatinib in urine was linear in the range from 1.9 × 10⁻⁸ to 1.9 × 10⁻⁶ M in stripping mode with an accumulation time (t_acc) of 10 s. The relative standard deviations obtained for concentration levels of Imatinib as low as 2.0 × 10⁻⁷ M for square-wave was 2.17% (n = 9) and for stripping square-wave was 2.65% (n = 9) in the same day. The limits of detection for square-wave and stripping square-wave were 5.55 × 10⁻⁹ and 5.19 × 10⁻⁹ M, respectively. Thus, the presented method are straightforward, rapid and sensitive and has been applied to the determination of Imatinib and its main metabolite altogether in urine samples from real patients.     

Tuning the selectivity of polymeric ionic liquid sorbent coatings for the extraction of polycyclic aromatic hydrocarbons using solid-phase microextraction

A new generation polymeric ionic liquid (PIL), poly(1-4-vinylbenzyl)-3-hexadecylimidazolium bis[(trifluoromethyl)sulfonyl]imide (poly(VBHDIm⁺ NTf₂⁻)), was synthesized and is shown to exhibit impressive selectivity towards the extraction of 12 polycyclic aromatic hydrocarbons (PAHs) from aqueous samples when used as a sorbent coating in direct-immersion solid-phase microextraction (SPME) coupled to gas chromatography (GC). The PIL was imparted with aromatic character to enhance π–π interactions between the analytes and the sorbent coating. For comparison purposes, a PIL with similar structure but lacking the π–π interaction capability, poly(1-vinyl-3-hexadecylimidazolium bis[(trifluoromethyl)sulfonyl]imide) (poly(HDIm⁺ NTf₂⁻)), as well as a commercial polydimethylsiloxane (PDMS) sorbent coating were evaluated and exhibited much lower extraction efficiencies. Extraction parameters, including stir rate and extraction time, were studied and optimized. The detection limits of poly(VBHDIm⁺ NTf₂⁻), poly(HDIm⁺ NTf₂⁻), and PDMS coatings varied between 0.003–0.07 μg L⁻¹, 0.02–0.6 μg L⁻¹, and 0.1–6 μg L⁻¹, respectively. The partition coefficients (log K_fs) of eight PAHs to the three studied fiber coatings were estimated using a static SPME approach. This study represents the first report of analyte partition coefficients to any PIL-based material.     

Voltammetric behaviour of the synthetic pyrethroid lambda-cyhalothrin and its determination in soil and well water

The pyrethroid lambda-cyhalothrin is a common insecticide which is widespread in the environment. A study of the electrochemical reduction of the pesticide on a hanging mercury drop electrode (HMDE) was performed as basis for the development of a sensitive analytical method for determination of lambda-cyhalothrin in natural samples. Two electrochemical techniques—cyclic voltammetry (CV) and differential pulse voltammetry (DPV)—were applied. The study was performed in the pH range 2-13 using Britton-Robinson (B-R) buffer to control the pH of the measuring solutions and tetrabutylammonium chloride (TBAC) salt as supporting electrolyte. In DPV, a single reduction peak was observed at both pH<4.0 and pH>10.5 while two cathodic peaks were produced in the pH range 4.0-10.5. The results showed that the reduction of lambda-cyhalothrin in the measuring solution is irreversible. The limiting current was found to be diffusion-controlled and free of adsorption of the electroactive species to HMDE over the whole pH range tested. For the analytical DPV method running at pH 2 the relationship between peak current and lambda-cyhalothrin concentration was linear up to 500 μg l⁻¹ (1.1×10⁻⁶ mol l⁻¹) with a detection limit of 2.5 μg l⁻¹. The repeatability in terms of relative standard deviation (n=10) was in the order of 3.5% at concentration levels of 5 and 10 μg l⁻¹. A DPV method for determining lambda-cyhalothrin in the agrochemical formulation Karate, spiked soil and well water was developed. The recovery was about 94% in well water and 92% in soil samples at concentration range of 0.05-0.5 μg l⁻¹ and 0.05-0.5 μg g⁻¹, respectively.     

Determination of aluminium in water samples by adsorptive cathodic stripping voltammetry in the presence of pyrogallol red and a quaternary ammonium salt

A fast, sensitive and selective method for the determination of aluminium based on the reaction of the metal with pyrogallol red (PR) in the presence of tetrabutylammonium tetrafluoroborate (TBATFB) to form an Al(PR)₃x9TBATFB complex which is adsorbed on the mercury electrode is presented. Under these conditions complexation of aluminium is rapid and no waiting period or heating of the sample is required. The reduction current of the accumulated complex is measured by scanning the potential in the cathodic direction. The variation of peak current with pH, adsorption time, adsorption potential, ligand and quaternary ammonium salt concentration, and some instrumental parameters, such as stirring rate in the accumulation stage, and step amplitude, pulse amplitude and step duration while obtaining the square wave voltamperograms were optimized. The best experimental parameters were pH 8.5, (NH₄Ac-NH₃ buffer), C_PR = 25 μmol L⁻¹, C_TBATFB over 75 μmol L⁻¹, t_ads = 60 s, and E_ads = −0.60 V versus Ag/AgCl. A linear response is observed over the 0.0-30.0 μg L⁻¹ concentration range, with a detection limit of 1.0 μg L⁻¹. Reproducibility for 9.0 μg L⁻¹ aluminium solution was 2.3% (n = 6). Synthetic sea water and sea water reference material CRM-SW were used for validation measurements. Aluminium in urine samples of a volunteer who ingested 800 mg of Al(OH)₃ was analyzed.     

Determination of trace aluminium by adsorptive stripping voltammetry on a preplated bismuth-film electrode in the presence of cupferron

This work reports the use of adsorptive stripping voltammetry (AdSV) for the determination of aluminium on a rotating-disc bismuth-film electrode (BiFE). Al(III) ions in the non-deoxygenated sample were complexed with cupferron and the complex was accumulated by adsorption on the surface of the preplated BiFE. The stripping step was carried out by using a square-wave (SW) potential-time voltammetric excitation signal. The experimental variables as well as potential interferences were investigated and the figures of merit of the method were established. Using the selected conditions, the 3σ limit of detection for aluminium was 0.5 μg l⁻¹ at a preconcentration time of 240 s and the relative standard deviation was 4.2% at the 5 μg 1⁻¹ level for a preconcentration time of 120 s (n = 8). The accuracy of the method was established by analysing water and metallurgical samples.     

Voltammetry and determination of metronidazole at a carbon fiber microdisk electrode

The electrochemistry of metronidazole, 1-(hydroxyethyl)-2-methyl-5-nitroimidazole, was investigated at a carbon fiber microdisk electrode in pH 9 Britton Robinson buffer. Under these conditions, the reduction of metronidazole is controlled by both mass transport to the microdisk and adsorption with an equilibrium constant of 4 × 10³ mol⁻¹ dm³ and a saturation coverage of 0.88 × 10⁻⁸ mol cm⁻². The adsorption and accumulation of metronidazole on the surface of the carbon fiber allows its determination at low concentrations by square wave adsorptive stripping voltammetry. A detection limit for metronidazole of 5 × 10⁻⁷ mol dm⁻³ and a R.S.D. of 3.7% at 1 × 10⁻⁶ mol dm⁻³ (n = 4) were obtained with a two electrode system with no stirring during the accumulation step. Based on this method, a simple procedure for the determination of metronidazole in urine is described which requires no pre-treatment of the sample before analysis.     

A chelating resin containing S, N and O atoms: Synthesis and adsorption properties for Hg(II)

A novel chelating resin containing S, N and O atoms (PSME-EDA) was synthesized by using poly(2-hydroxyethylmercaptomethylstyrene) (PSME) and diethanolamine (EDA) as materials. Its structure was characterized by elemental analysis, Fourier transform-infrared spectra (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The adsorption of the resin for Hg²⁺ was investigated. The saturated adsorption capacity of PSME-EDA for Hg²⁺ could reach to about 1.1 mmol/g at 25 °C when the initial Hg²⁺ concentration was 0.02 mol/l. Some factors affecting the adsorption such as temperature, reaction time and ion concentration were also studied. The results showed that adsorption was controlled by liquid film diffusion. The increasing of temperature was beneficial to adsorption. The Langmuir model was better than the Freundlich model to describe the isothermal process. The values of ΔG, ΔH, and ΔS calculated at 25 °C were −7.99 kJ mol⁻¹, 22.5 kJ mol⁻¹ and 34.4 J mol⁻¹ K⁻¹, respectively. The adsorption mechanism of PSME-EDA resin for Hg(II) was confirmed by X-ray photoelectron spectroscopy (XPS).     

Simultaneous determination of nickel(II) and cobalt(II) by square wave adsorptive stripping voltammetry on a rotating-disc bismuth-film electrode

This works reports the use of square-wave adsorptive stripping voltammetry (SWAdSV) for the simultaneous determination of Ni(II) and Co(II) on a rotating-disc bismuth-film electrode (BFE). The metal ions in the non-deoxygenated sample were complexed with dimethylglyoxime (DMG) and the complexes were accumulated by adsorption on the surface of the BFE. The stripping step was carried out by using a square-wave potential-time voltammetric excitation signal. Electrochemical cleaning of the bismuth film was employed, enabling the same bismuth film to be used for a series of measurements. The experimental variables (choice of the working electrode substrate, the presence of oxygen, the DMG concentration, the buffer concentration, the preconcentration potential, the accumulation time, the rotation speed and the SW parameters) as well as potential interferences were investigated and the figures of merit of the methods were established. Using the selected conditions, the 3σ limits of detection were 70 ng l⁻¹ for Co(II) and 100 ng l⁻¹ for Ni(II) (for 300 s of preconcentration) and the relative standard deviations were 2.3% for Co(II) and 3.9% for Ni(II) at the 2 μg l⁻¹ level (n = 8). Finally, the method was applied to the determination of nickel and cobalt in real samples with satisfactory results.     

Determination of palladium in various samples by atomic absorption spectrometry after preconcentration with dimethylglyoxime on silica gel

A preconcentration method based on the adsorption of palladium-dimethylglyoxime (DMG) complex on silica gel for the determination of palladium at trace levels by atomic absorption spectrometry (AAS) has been developed. The retained palladium as Pd(DMG)₂ complex was eluted with 1 mol l⁻¹ HCl in acetone. The effect of some analytical parameters such as pH, amount of reagent and the sample volume on the recovery of palladium was examined in synthetic solutions containing street dust matrix. The influence of some matrix ions on the recovery of palladium was investigated by using the developed method when the elements were present both individually and together. The results showed that 2500 μg ml⁻¹ Na⁺, K⁺, Mg²⁺, Al³⁺ and Fe³⁺; 5000 μg ml⁻¹ Ca²⁺ ; 500 μg ml⁻¹ Pb²⁺; 125 μg ml⁻¹ Zn²⁺; 50 μg ml⁻¹ Cu²⁺ and 25 μg ml⁻¹ Ni²⁺ did not interfere with the palladium signal. At the optimum conditions determined experimentally, the recovery for palladium was found to be 95.3±1.2% at the 95% confidence level. The relative standard deviation and limit of detection (3s/b) of the method were found to be 1.7% and 1.2 μg l⁻¹, respectively. In order to determine the adsorption behaviour of silica gel, the adsorption isotherm of palladium was studied and the binding equilibrium constant and adsorption capacity were calculated to be 0.38 l mg⁻¹ and 4.06 mg g⁻¹, respectively. The determination of palladium in various samples was performed by using both flame AAS and graphite furnace AAS. The proposed method was successfully applied for the determination of palladium in the street dust, anode slime, rock and catalytic converter samples.     

Determination of trace heavy metals in herbs by sequential injection analysis-anodic stripping voltammetry using screen-printed carbon nanotubes electrodes

A method for the simultaneous determination of Pb(II), Cd(II), and Zn(II) at low μg L⁻¹ concentration levels by sequential injection analysis-anodic stripping voltammetry (SIA-ASV) using screen-printed carbon nanotubes electrodes (SPCNTE) was developed. A bismuth film was prepared by in situ plating of bismuth on the screen-printed carbon nanotubes electrode. Operational parameters such as ratio of carbon nanotubes to carbon ink, bismuth concentration, deposition time and flow rate during preconcentration step were optimized. Under the optimal conditions, the linear ranges were found to be 2-100 μg L⁻¹ for Pb(II) and Cd(II), and 12-100 μg L⁻¹ for Zn(II). The limits of detection (S_bl/S = 3) were 0.2 μg L⁻¹ for Pb(II), 0.8 μg L⁻¹ for Cd(II) and 11 μg L⁻¹ for Zn(II). The measurement frequency was found to be 10-15 stripping cycle h⁻¹. The present method offers high sensitivity and high throughput for on-line monitoring of trace heavy metals. The practical utility of our method was also demonstrated with the determination of Pb(II), Cd(II), and Zn(II) by spiking procedure in herb samples. Our methodology produced results that were correlated with ICP-AES data. Therefore, we propose a method that can be used for the automatic and sensitive evaluation of heavy metals contaminated in herb items.     

Adsorption of a protein-porphyrin complex at a liquid-liquid interface studied by total internal reflection synchronous fluorescence spectroscopy

Interfacial analysis has attracted more and more attention owing to its fundamental and biological importance. Total internal reflection fluorescence (TIRF) spectroscopy is a useful method to study interfacial properties. The synchronous scanning fluorescence technique provides a selective tool to analyze a specific component in a complex system. The interaction and adsorption of bovine serum albumin (BSA) and meso-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) at toluene-water interface were studied successfully by the coupling technique of total internal reflection synchronous fluorescence (TIRSF). New methods are provided for the determination of the critical micelle concentration (cmc), apparent adsorption equilibrium constant (K_ad) and maximum amount of adsorption (f_max) at the liquid-liquid interface. The results indicated that BSA could adsorb onto the toluene-water interface as a complex of BSA-TPPS in a ratio of 1:1 ratio based on Langmuir adsorption isothermal model. The cmc, apparent K_ad and f_max for BSA at pH 3.1 were determined to be 1.0 × 10⁻⁴ mol L⁻¹, 1.15 × 10⁵ L mol⁻¹ and 1.14 × 10⁻⁹ mol cm⁻², respectively.     

Simple hollow fiber renewal liquid membrane extraction method for pre-concentration of Cd(II) in environmental samples and detection by Flame Atomic Absorption Spectrometry

A hollow fiber renewal liquid membrane (HFRLM) extraction method to determine cadmium (II) in water samples using Flame Atomic Absorption Spectrometry (FAAS) was developed. Ammonium O,O-diethyl dithiophosphate (DDTP) was used to complex cadmium (II) in an acid medium to obtain a neutral hydrophobic complex (ML₂). The organic solvent introduced to the sample extracts this complex from the aqueous solution and carries it over the poly(dimethylsiloxane) (PDMS) membrane, that had their walls previously filled with the same organic solvent. The organic solvent is solubilized inside the PDMS membrane, leading to a homogeneous phase. The complex strips the lumen of the membrane where, at higher pH, the complex Cd-DDTP is broken down and cadmium (II) is released into the stripping phase. EDTA was used to complex the cadmium (II), helping to trap the analyte in the stripping phase. A multivariate procedure was used to optimize the studied variables. The optimized variables were: sample (donor phase) pH 3.25, DDTP concentration 0.05% (m/v), stripping (acceptor phase) pH 8.75, EDTA concentration 1.5 × 10⁻² mol L⁻¹, extraction temperature 40 °C, extraction time 40 min, a solvent mixture N-butyl acetate and hexane (60/40%, v/v) with a volume of 100 μL, and addition of ammonium sulfate to saturate the sample. The sample volume used was 20 mL and the stripping volume was 165 μL. The analyte enrichment factor was 120, limit of detection (LOD) 1.3 μg L⁻¹, relative standard deviation (RSD) 5.5% and the working linear range 2-30 μg L⁻¹.     

Determination of water pollutants by direct-immersion solid-phase microextraction using polymeric ionic liquid coatings

The determination of a group of eighteen pollutants in waters, including polycyclic aromatic hydrocarbons and substituted phenols, is conducted in direct-immersion solid-phase microextraction (SPME) using the polymeric ionic liquid (PIL) poly(1-vinyl-3-hexadecylimidazolium) bis[(trifluoromethyl)sulfonyl]imide as a novel coating material. The performance of the PIL fiber coating in the developed IL-SPME-gas chromatography (GC)–mass spectrometry (MS) method is characterized by average relative recoveries of 92.5% for deionized waters and 90.8% for well waters, average precision values (as relative standard deviations, RSD%) of 11% for deionized waters and 12% for well waters, using a spiked level of 5 ng mL⁻¹. The detection limits oscillate from 0.005 ng mL⁻¹ for fluoranthene to 4.4 ng mL⁻¹ for 4-chloro-3-methylphenol, when using an extraction time of 60 min with 20 mL of aqueous sample. The extraction capabilities of the PIL fiber have been compared with the commercial SPME coatings: polydimethylsyloxane (PDMS) 30 μm, PDMS 100 μm and polyacrylate (PA) 85 μm. The PIL fiber is superior to the PDMS 30 μm for all analytes studied. A qualitative study was also carried out to compare among the nature of the coating materials by normalizing the coating thickness. The PIL material was shown to be more efficient than the PDMS material for all analytes studied. The PIL coating was also adequate for nonpolar analytes whereas the PA material was more sensitive for polar compounds.