Dispersive Liquid-liquid Microextraction Method Research Articles

Separation and Determination of Copper in Bottled Water Samples by Combination of Dispersive Liquid–Liquid Microextraction and Microsample Introduction Flame Atomic Absorption Spectrometry

A new and simple method for the determination of trace amounts of Cu(II) was developed by combination of dispersive liquid-liquid microextraction (DLLME) preconcentration and microsample introduction flame atomic absorption spectrometry. In this method, ethanol and chloroform were chosen as disperser and extraction solvents, respectively, and 1-nitroso-2-naphthol was used as the complexing agent. The factors affecting the extraction efficiency and determination of Cu(II), including extraction and disperser solvent nature and volume, concentration of the complexing agent, pH of the solution, extraction time, and matrix ions, were investigated. Under optimal conditions, the LOD for Cu(II) was 0.95 microg/L with a preconcentration factor of 70. The RSD was 1.9%. The accuracy of the developed DLLME method was verified by determination of Cu(II) in a certified reference material (NRCC-SLRS-4 river water). The relative error was -3.31%. The developed preconcentration procedure was successfully applied to the analysis of bottled drinking water samples.

Assessment of dispersive liquid–liquid microextraction for the simultaneous extraction, preconcentration, and derivatization of Hg2+ and CH3Hg+ for further determination by GC–MS

This work reports the development of a dispersive liquid-liquid microextraction method for the simultaneous extraction, preconcentration, and derivatization of Hg(2+) and CH3Hg(+) species from water samples for further determination by GC-MS. Some parameters of the proposed method, such as volume and type of disperser and extraction solvent, and Na[B(C6H5)4] concentration were investigated using response surface methodology. Suitable recoveries were obtained using 80 μL C2 Cl4 (as extraction solvent), 1000 μL ethanol (as disperser solvent), and 300 μL 2.1 mmol/L Na[B(C6H5)4] (as derivatizing agent). Accuracy was evaluated in terms of recovery and ranged from 87 to 99% with RSD values <7%. In addition, a certified reference material of water (NIST 1641d) was analyzed and agreed with the certified value about 107% (for Hg(2+)), with RSD values <8.5%. LODs were 0.3 and 0.2 μg/L, with enrichment factors of 112 and 115 for Hg(2+) and CH3Hg(+), respectively. The optimized method was applied for the determination of Hg(2+) and CH3Hg(+) in tap, well, and lake water samples.

Concerted derivatization and concentration method with dispersive liquid–liquid microextraction for liquid chromatographic analysis of 5-hydroxyindoles in human serum

We developed a concerted derivatization and concentration method based on dispersive liquid-liquid microextraction (DLLME) for the liquid chromatography (LC) determination of 5-hydroxyindoles (5-HIs; serotonin, 5-hydroxyindole-3-acetic acid, N-acetylserotonin, and 5-hydroxytryptohol). Concerted derivatization and concentration could be affected by adding a mixture of an ionic liquid (1-hexyl-3-methylimidazolium hexafluorophosphate, extraction solvent), methanol (disperser), and water containing fluorescence derivatization reagents [benzylamine and potassium hexacyanoferrate(III)] into the sample. The resulting sedimented phase was injected into a reversed-phase LC column using a mixture of acetonitrile and 250 mM acetate buffer (pH 4.3) as the mobile phase for gradient elution, and the derivatives obtained were fluorometrically detected at excitation and emission wavelengths of 345 nm and 452 nm, respectively. The derivatization (reagent concentrations and pH) and extraction (extraction and disperser solvent type) conditions were optimized simultaneously. The limits of detection of the 5-HIs were in the range of 0.08-0.33 nM. The method was validated for 10 and 50 pmol/mL human serum levels, and the recovery of 5-HIs was between 66% and 98%, within a relative standard deviation of 9.5%. The proposed method is well suited for the highly sensitive analysis of trace amounts of 5-HIs in human serum samples.

Comparison of two ultrasound‐enhanced microextractions combined with HPLC for determining acaricides in water

An ultrasound-enhanced in situ solvent formation microextraction has been developed first time and compared with ultrasound-enhanced ionic-liquid-assisted dispersive liquid-liquid microextraction for the HPLC analysis of acaricides in environmental water samples. A ionic liquid ([C8MIM][PF6]) was used as the green extraction solvent through two pathways. The experimental parameters, such as the type and volume of both of the extraction solvent disperser solvent, ultrasonication time, and salt addition, were investigated and optimized. The analytical performance using the optimized conditions proved the feasibility of the developed methods for the quantitation of trace levels of acaricides by obtaining limits of detection that range from 0.54 to 3.68 μg/L. The in situ solvent formation microextraction method possesses more positive characteristics than the ionic-liquid-assisted dispersive liquid-liquid microextraction method (except for spirodiclofen determination) when comparing the validation parameters. Both methods were successfully applied to determining acaricides in real water samples.

A Simple Device for Collection of Extraction Phase in Dispersive Liquid-Liquid Microextraction Method Based on Solidification of Floating Organic Droplet for Sensitive Determination of Curcumin in Human Serum

A narrow neck glass tube was used for simple and rapid collection of organic phase from the sample surface in dispersive liquid-liquid microextraction method based on solidification of floating organic droplet (DLLME-SFO) after its centrifugation and cooling in a water bath. The method was used for preconcentration and sensitive determination of curcumin in human serum. In the designed method, curcumin was extracted from a mixture of serum and acetone (disperser solvent) into 50 ml 1-dodecanol (organic solvent) after its rapid injection into 4.5 mL of an aqueous medium. Factorial design and central composite design methods were used for optimization of the effects of ionic strength, extraction and disperser solvents’ volumes and pH. Spectrophotometric determinations of the extracts at 419 nm were used during the optimization, but for the serum samples the extracts were injected into an HPLC column for final determinations. In the optimized conditions, quantitative extraction of curcumin from serum samples was achieved with a mean recovery of 95.5 % and an RSD of 8.0 % for six replicates. The calibration curve for the HPLC method was linear up to 4 mg mL−1 with a correlation coefficient of 0.990. Enrichment factors exceeding 25.3 was obtained for curcumin. The detection limit of the method was calculated from 3 s to be as low as 1.2 ng mL−1. The method was applied to the determination of curcumin in several human serum samples with satisfactory results.

Determination of phthalate esters in bottled water using dispersive liquid–liquid microextraction coupled with GC–MS

Dispersive liquid-liquid microextraction method was developed for the determination of the amount of phthalate esters in bottled drinking water samples and dispersive liquid-liquid microextraction samples were analyzed by GC-MS. Various experimental conditions influencing the extraction were optimized. Under the optimized conditions, very good linearity was observed for all analytes in a range between 0.05 and 150 μg/L with coefficient of determination (R²) between 0.995 and 0.999. The LODs based on S/N = 3 were 0.005-0.22 μg/L. The reproducibility of dispersive liquid-liquid microextraction was evaluated. The RSDs were 1.3-5.2% (n = 3). The concentrations of phthalates were determined in bottled samples available in half shell. To understand the leaching profile of these phthalates from bottled water, bottles were exposed to direct sunlight during summer (temperature from 34-57°C) and sampled at different intervals. Result showed that the proposed dispersive liquid-liquid microextraction is suitable for rapid determination of phthalates in bottled water and di-n-butyl, butyl benzyl, and bis-2-ethylhexyl phthalate compounds leaching from bottles up to 36 h. Thereafter, degradation of phthalates was observed.

Surfactant-enhanced liquid-liquid microextraction coupled to micro-solid phase extraction onto highly hydrophobic magnetic nanoparticles

We are presenting a simplified alternative method for dispersive liquid-liquid microextraction (DLLME) by resorting to the use of surfactants as emulsifiers and micro solid-phase extraction (μ-SPE). In this combined procedure, DLLME of hydrophobic components is initially accomplished in a mixed micellar/microemulsion extractant phase that is prepared by rapidly mixing a non-ionic surfactant and 1-octanol in aqueous medium. Then, and in contrast to classic DLLME, the extractant phase is collected by highly hydrophobic polysiloxane-coated core-shell Fe2O3@C magnetic nanoparticles. Hence, the sample components are the target analyte in the DLLME which, in turn, becomes the target analyte of the μ-SPE step. This 2-step approach represents a new and simple DLLME procedure that lacks tedious steps such as centrifugation, thawing, or delicate collection of the extractant phase. As a result, the analytical process is accelerated and the volume of the collected phase does not depend on the volume of the extraction solvent. The method was applied to extract cadmium in the form of its pyrrolidine dithiocarbamate chelate from spiked water samples prior to its determination by FAAS. Detection limits were brought down to the low μg L−1 levels by preconcentrating 10 mL samples with satisfactory recoveries (96.0–108.0 %).

Dispersive liquid–liquid microextraction for the high performance liquid chromatographic determination of aldehydes in cigarette smoke and injectable formulations

A dispersive liquid–liquid microextraction method (DLLME) combined with high performance liquid chromatography (HPLC) was developed for the extraction and determination of some aldehydes, such as benzaldehyde (BzA), butyraldehyde (BuA) and furfural (Fur) in mainstream cigarette smoke as well as BzA in injectable formulations. After trapping of combustion smoke into sulfuric acid with a laboratory-made smoking machine, aldehydes were converted into their hydrazone derivatives by the reaction with 2,4-dinitrophenylhydrazine (DNPH), and then rapidly extracted by DLLME. The effects of various experimental parameters on the derivatization and extraction were studied and optimized. Under the optimum extraction conditions, linear calibration curves in the range 0.025 to 1.0μg/mL with correlation coefficients of 0.9980–0.9996 were obtained for studied aldehydes. Limit of detections (LODs) for BzA, BuA and Fur were found to be 14.2, 21.3 and 7.92μg/L, respectively. The relative standard deviations (RSDs) for inter–and intra–day assays were lower than 8.50%. Average recoveries for spiked samples were in the range 88.0–109%. The proposed method was successfully applied to the determination of aldehydes in different real samples.

Combination of saponification and dispersive liquid–liquid microextraction for the determination of tocopherols and tocotrienols in cereals by reversed-phase high-performance liquid chromatography

A simple sample preparation technique coupled with reversed-phase high-performance liquid chromatography was developed for the determination of tocopherols and tocotrienols in cereals. The sample preparation procedure involved a small-scale hydrolysis of 0.5g cereal sample by saponification, followed by the extraction and concentration of tocopherols and tocotrienols from saponified extract using dispersive liquid–liquid microextraction (DLLME). Parameters affecting the DLLME performance were optimized to achieve the highest extraction efficiency and the performance of the developed DLLME method was evaluated. Good linearity was observed over the range assayed (0.031–4.0μg/mL) with regression coefficients greater than 0.9989 for all tocopherols and tocotrienols. Limits of detection and enrichment factors ranged from 0.01 to 0.11μg/mL and 50 to 73, respectively. Intra- and inter-day precision were lower than 8.9% and the recoveries were around 85.5–116.6% for all tocopherols and tocotrienols. The developed DLLME method was successfully applied to cereals: rice, barley, oat, wheat, corn and millet. This new sample preparation approach represents an inexpensive, rapid, simple and precise sample cleanup and concentration method for the determination of tocopherols and tocotrienols in cereals.

Highly sensitive and selective organophosphate screening in twelve commodities of fruits, vegetables and herbal medicines by dispersive liquid–liquid microextraction

The article describes a simple sample pretreatment procedure for the analysis of ten organophosphorus pesticides using dispersive liquid–liquid microextraction (DLLME) followed by gas chromatography–mass spectrometry (GC–MS) in three distinctively different types of matrices: fresh fruits, fresh vegetables and dried herbs. The method was carefully developed, focusing on the chemistry of various dispersive solvents, to achieve simultaneous, comprehensive extraction and preconcentration in a great span of selected matrices. According to matrix-matched validation study, the set of optimized DLLME conditions has been proven robust to determine target OPPs within a wide linear range from 0.1 to 1000μgL−1. With limited usage of organic extractants, remarkable enrichment factors up to 100-fold were obtained, enabling ultra-trace pesticide quantification down to sub-ppt levels at 0.12–4.92ngkg−1. Practical application of the method was illustrated by quantitative recovery (70–119%) and good precision (2.6–10% R.S.D.) in a representative range of three fruits and four vegetable commodities featured by the CODEX Alimentarius classification as well as their unique matrix compositions. A careful selection of dried herbs was further classified based on their morphological structures to validate analytical ruggedness of the method. Compared with existing methods for food analysis vis-à-vis OPPs, the present method is superior in terms of high sample throughput, minimal solvent consumption, and small sample size requirement. An additional, significant aspect of this universal DLLME method is that it models sample pretreatment methods with wide coverage of analytical matrices that are more effective, more comprehensive, and more flexible than those currently being used.

Determination of priority pollutants in aqueous samples by dispersive liquid–liquid microextraction

A dispersive liquid–liquid microextraction (DLLME) method followed by high-performance liquid chromatography–triple quadrupole mass spectrometry has been developed for the simultaneous determination of linear alkylbenzene sulfonates (LAS C10, C11, C12, and C13), nonylphenol (NP), nonylphenol mono- and diethoxylates (NP1EO and NP2EO), and di-(2-ethylhexyl)phthalate (DEHP). The applicability of the method has been tested by the determination of the above mentioned organic pollutants in tap water and wastewater. Several parameters affecting DLLME, such as, the type and volume of the extraction and disperser solvents, sample pH, ionic strength and number of extractions, have been evaluated. Methanol (1.5mL) was selected among the six disperser solvent tested. Dichlorobenzene (50μL) was selected among the four extraction solvent tested. Enrichment factor achieved was 80. Linear ranges in samples were 0.01–3.42μg L−1 for LAS C10–13 and NP2EO, 0.09–5.17μgL−1 for NP1EO, 0.17–9.19μgL−1 for NP and 0.40–17.9μgL−1 for DEHP. Coefficients of correlation were higher than 0.997. Limits of quantitation in tap water and wastewater were in the ranges 0.009–0.019μgL−1 for LAS, 0.009–0.091μgL−1 for NP, NP1EO and NP2EO and 0.201–0.224μgL−1 for DEHP. Extraction recoveries were in the range from 57 to 80%, except for LAS C10 (30–36%). The method was successfully applied to the determination of these pollutants in tap water and effluent wastewater from Seville (South of Spain). The DLLME method developed is fast, easy to perform, requires low solvent volumes and allows the determination of the priority hazardous substances NP and DEHP (Directive 2008/105/EC).

Comparison of air-agitated liquid–liquid microextraction technique and conventional dispersive liquid–liquid micro-extraction for determination of triazole pesticides in aqueous samples by gas chromatography with flame ionization detection

Two micro-extraction methods, air-agitated liquid–liquid microextraction (AALLME) and dispersive liquid–liquid microextraction (DLLME), have been compared with each other by applying them for the analysis of five triazole pesticides (penconazole, hexaconazole, diniconazole, tebuconazole and triticonazole) in aqueous samples by gas chromatography with flame ionization detection (GC-FID). In the AALLME method, which excludes any disperser solvent, much less volume of organic solvent is used. In order to form fine and dispersed organic droplets in the aqueous phase, the mixture of aqueous sample solution and extraction solvent is repeatedly aspirated and dispensed with a syringe. In the DLLME method, an appropriate mixture of extraction solvent and disperser solvent is rapidly injected by a syringe into the aqueous sample. Effect of the pertinent experimental factors on DLLME (i.e. identity and volume of the extraction and disperser solvents and ionic strength) and on AALLME (identity and volume of the extraction solvent, number of agitations, and ionic strength) were investigated. Under optimal conditions, limits of detection for the five target pesticides obtained by AALLME-GC-FID and DLLME-GC-FID ranged from 0.20 to 1.1ngmL−1 and 1.9 to 5.9ngmL−1, respectively. The relative standard deviations (RSDs, n=5) were in the range of 1–4% and 3–5% with the enrichment factors of 449–504 and 79–143 for AALLME-GC-FID and DLLME-GC-FID, respectively. Both of the compared methods are simple, fast, efficient, inexpensive and can be applied to the analysis of the five pesticides in different aqueous samples in which penconazole and hexaconazole were found. For spiked samples, the recoveries were in the ranges of 92–105%, and 92–104% for AALLME and DLLME, respectively.

Rapid determination of α‐tocopherol in cereal grains using dispersive liquid–liquid microextraction followed by HPLC

The traditional for the determination of α-tocopherol in cereal grains includes saponification of a sample followed by liquid-liquid extraction, and it is time- and solvent consuming. In this study, a dispersive liquid-liquid microextraction (DLLME) method was developed to extract α-tocopherol in situ from the saponified grain sample solution. The DLLME experimental parameters including the type and volume of extractants, the volume of dispersers, the addition of salt and the extraction/centrifuging time were examined and optimized. The recommended analytical procedure showed excellent precision (relative SDs of the α-tocopherol amount of 3.1% over intraday and 7.2% over interday), high sensitivity (the detection limit of 1.9 ng/mL), and strong recovery values (88.9-102.5%). In addition, statistical analyses showed no significant difference between the detected amounts of α-tocopherol found by the standardized method and this new procedure. The method was successfully applied to determining the amounts and distribution of α-tocopherol in 14 cereal grain samples.

Determination of pesticide residues in ginseng by dispersive liquid–liquid microextraction and ultra high performance liquid chromatography–tandem mass spectrometry

A procedure involving acetonitrile-based extraction combined with dispersive liquid-liquid microextraction (DLLME) and detection by ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used for determination of 39 pesticides in ginseng. The extraction of pesticide residues in ginseng was performed with acetonitrile, applying QuEChERS methodology, and the extract was further disposed by DLLME method before analyzed by UHPLC-MS/MS. The average recoveries ranged from 70 to 120% for 82% of the analytes with RSD lower than 15%. The calibration curves obtained with blank matrices were linear with a correlation coefficient of over 0.99. The limits of detection were between 0.01 and 1.0μg/kg. Matrix effects were studied by comparing solvent calibration curves and matrix-matched calibration curves. The results indicate the feasibility of this method for the determination of 39 pesticides in ginseng.

Dispersive liquid-liquid microextraction of phenolic compounds using solidified floating organic droplets, and their determination by HPLC

We have developed a simple and efficient method for dispersive liquid-liquid microextraction of 4-nitrophenol, 2-naphthol and bisphenol A in real water samples. It is making use of solidified floating organic droplets of 1-dodecanol which has low density and a proper melting point. The type and volume of extraction solvent and dispersive solvent, the effect of salts, pH value and extraction time were optimized and resulted in enrichment factors of 84 for 4-nitrophenol, 123 for 2-naphthol, and 97 for bisphenol A. The limits of detection by HPLC are 1.50, 0.10 and 1.02 ng · mL−1, respectively. Excellent linearity is observed in the concentration range from 10 to 800 ng · mL−1, with coefficients of correlation ranging from 0.9988 to 0.9999. The relative standard deviations (for n = 5) are from 3.2 to 5.3 %, and relative recoveries for the three phenols in tap, river and spring water range from 85.0 to 105.0 %, 98.3 to 110.0 %, and 98.6 to 109.0 %, respectively.

Anin situIonic Liquid Dispersive Liquid-Liquid Microextraction Method for the Detection of Pyrethroids by LC-UV in Environmental Water Samples

An in situ ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) method was developed as a new approach for the detection of four pyrethroid pesticides in environmental water samples. The method is fast, simple, accurate and environmentally friendly. The hydrophobic ionic liquid, [C8MIM]-NTf2, formed by the water-soluble ionic liquid [C8MIM]Cl and the ion exchange reagent LiNTf2 was used as the extraction solvent. The experimental parameters affecting the extraction efficiency, including the amount of the IL, the extraction and the centrifugation times and the salt concentration were investigated and optimized using an orthogonal array design (OAD). A suitable molar ratio of LiNTf2 to [C8MIM]Cl on the recoveries of analytes was determined after OAD optimization. The method showed a good linear response in the range of 0.5 to 500 µg L-1 with correlation coefficients (R2) above 0.9998. The relative standard deviation (RSD) varied from 0.6 to 1.9%. The enrichment factor, the limit of detection and recovery ranged from 134 to 153, 0.02 to 0.18 µg L-1 and 89.7 to 95.6%, respectively. For water samples, the RSD ranged from 0.02 to 2.34% and the recovery ranges from 91.4 to 99.9%.

Optimization and validation of a new pesticide residue method for cucumber and tomato using acetonitrile-based extraction-dispersive liquid–liquid microextraction followed by liquid chromatography-tandem mass spectrometry

A multiclass and multi-residue method was optimized and validated for analysis of 19 pesticides of 16 chemical classes in greenhouse cucumber and tomato followed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). In this study a dispersive liquid–liquid microextraction (DLLME) technique was applied for extraction and pre-concentration of pesticide residues from QuEChERS (quick, easy, cheap, effective, rugged and safe) extracts. The DLLME method was carried out using carbon tetrachloride as the extraction solvent and QuEChERS extract as the dispersive solvent. The main parameters affecting DLLME efficiency including the type and volume of extraction solvent and the volume of dispersive solvent and salt addition were optimized for the proposed method. To validate this developed method, recovery studies were carried out at two concentration levels, yielding mean recovery rates in the range of 86 to 104% with relative standard deviations below 12%. Good linearity and precision, with relative standard deviations generally below 10%, were obtained for all 19 pesticides. The method limits of detection (LOD) between 3.4 and 10.4 μg kg−1 and method limits of quantification (LOQ) in the range of 11.2–34.5 μg kg−1 were obtained for the proposed method. Recovery rates and method LODs and LOQs of the validated method were compared with those of the routine QuEChERS method and results indicated the efficiency of the proposed method for routine analysis of 19 pesticide residues in cucumber and tomato.

Determination of Trace Amounts of Lead with ETAAS After Single Drop Microextraction and Dispersive Liquid Liquid Microextraction Methods

Two liquid-phase microextraction procedures, single-drop microextraction (SDME) and dispersive liquid–liquid microextraction (DLLME), have been developed for the determination of lead by electrothermal atomic absorption spectrometry (ETAAS). Both methods were based on the formation of lead iodide-Rhodamine B complex which is in phosphoric acid medium. In the presence of KI, anionic lead iodide was complexed with Rhodamine B as an ion-association complex. Several factors that may be affected on the SDME and DLLME methods were optimized. In the optimum experimental conditions, the limit of detection (3s) and the enhancement factor were 0.008 μgL −1 and 152 for SDME and 0.0129 μgL −1 and 89 for DLLME respectively. The relative standard deviation (RSD) for eight replicate determinations of 0.25 μgL −1 Pb was 4.6% for SDME and 0.5 μgL −1 Pb was 2.9% for DLLME. The developed methods were validated by the analysis of certified reference materials, and applied successfully to the determination of lead in several water and food samples.

Ultrasound-Assisted Ion-Pair Dispersive Liquid–Liquid Microextraction of Trace Amounts of Lead in Water Samples Prior to Graphite Furnace Atomic Absorption Spectrometry Determination

A new ion-pair dispersive liquid-liquid microextraction method is described for separation and preconcentration of trace amounts of lead in different water samples. Graphite furnace atomic absorption spectrometry was used for determination of lead. The ion association complex between lead and iodide ions that forms is PbI4(-2)-tetradecyl-dimethylbenzylammonium, which is extracted into fine droplets of chlorobenzene. In order to reach the optimized experimental conditions, the influence of different parameters, such as concentration of KI, nature and volume of extraction solvents, pH effect, extraction time, and the period and speed of sonication and centrifugation, were optimized. The LOD was 0.08 ng/mL and the linear dynamic range was 0.20-8.0 ng/mL in initial solution with a correlation coefficient of 0.9985. Under the optimum conditions, the enrichment factor was 555.5. The proposed method was successfully applied for separation and determination of lead in sea, rain, river, and drinking water samples.

Selective preconcentration of silver by one-step displacement dispersive liquid–liquid microextraction and determination by graphite furnace atomic absorption spectrometry

A simple and rapid one-step displacement dispersive liquid–liquid microextraction method (D-DLLME) was developed for the selective preconcentration of silver followed by graphite furnace atomic absorption spectrometry determination. In the proposed method, Cu was reacted with diethyldithiocarbamate (DDTC) to form a Cu–DDTC complex, and it was used as a chelating agent instead of DDTC for dispersive liquid–liquid microextraction (DLLME) of silver. Because the stability of Ag–DDTC is higher than that of Cu–DDTC, Ag can displace Cu from the Cu–DDTC complex and be preconcentrated in a single DLLME procedure. Potential interference from co-existing metal ions with lower DDTC complex stability was largely eliminated as they cannot displace Cu from the Cu–DDTC complex, and the tolerance limits for these ions were improved by a long way compared with the conventional DLLME method. Under the optimal conditions, the limit of detection of this method was 16 ng L−1 (3σ) for silver, and an enhancement factor of 82 was achieved with a sample volume of 5.0 mL. The proposed method was successfully applied for the determination of trace silver in some environmental and biological samples with satisfactory results.