A flow-batch lab-in-syringe foam microextraction platform for the simultaneous preconcentration and in situ membraneless gas-liquid separation of mercury prior to cold vapor atomic absorption spectrometry.

Herein, the proof-of-concept of a novel lab-in-syringe (LIS) foam microextraction platform is presented as a front-end to cold vapor atomic absorption spectrometry (CVAAS) for the simultaneous preconcentration and membraneless gas-liquid separation (GLS) of inorganic mercury in biological samples. The proposed method is based on the on-line formation of the ammonium pyrrolidine dithiocarbamate complex with mercury that was retained in the pores of polyurethane foam immobilized on the piston of the LIS system. Metal complex elution and in situ mercury vapor generation are accomplished inside the microsyringe in a flow-batch format, while the separation of vapor species is achieved via the membraneless GLS found at the top of the syringe's barrel. Under optimized operation conditions, for 90 s preconcentration time, the limit of detection was 0.02 µg L-1 and the repeatability (RSD) was 3.8% (at the 0.5 µg L-1 concentration level), within a working range extending up to 4.0 µg L-1. The practicality of the novel manifold was demonstrated using the Blue Applicability Grade Index, while the accuracy of the method was evaluated using certified reference materials and spiked samples.

Dual Lab-in-Syringe Flow-Batch Platform for Automatic Fabric Disk Sorptive Extraction/Back-extraction as a Front End to Inductively Coupled Plasma Atomic Emission Spectrometry.

A novel dual lab-in-syringe flow-batch (D-LIS-FB) platform for automatic fabric-disk-in-syringe sorptive extraction followed by oxidative back-extraction as a front end to inductively coupled plasma atomic emission spectrometry (ICP-AES) is presented for the first time. Sol-gel poly(caprolactone)-poly(dimethylsiloxane)-poly(caprolactone)-coated polyester fabric disks were packed at the top of the glass barrel of a microsyringe pump as an alternative to column preconcentration. Herein lie multiple significant advantages including effectiveness, compactness, lower back-pressure, and lower time of analysis. Copper, lead, and cadmium were used as model analytes for the exploration of the capabilities of the developed platform. The online retained metal-diethyldithiophosphate complexes were eluted using diisopropyl ketone prior to atomization. Undesirable incompatibility of organic solvents for direct injection into the ICP-AES system was overcome ingeniously in a flow manner by oxidative back-extraction of the analytes utilizing a second lab-in-syringe setup. Following its optimization, the D-LIS-FB platform showed excellent linearity, in combination with good method precision (i.e., RSD < 3.4%) and trueness. Moreover, the limits of detection were 0.25 µg L-1 for Cd(II), 0.13 µg L-1 for Cu(II), and 0.37 µg L-1 for Pb(II), confirming the applicability of the proposed system for metal analysis at trace levels. As a proof-of-concept, the developed versatile system was utilized for the analysis of different environmental, food, and biological samples.

A novel automatic flow-batch extraction induced by emulsion breaking platform for on-line copper determination in edible oil samples by atomic absorption spectrometry.

A novel automatic flow-batch platform coupled with atomic spectrometry for on-line acidic extraction induced by emulsion breaking with heating (FB-EIEBH) for metal determination in edible oils (corn, sunflower and olive oil), was developed for the first time. The proposed system was demonstrated for copper determination in conjunction with flame atomic absorption spectrometry. The extraction of metal is accomplished after the oil emulsification with an aqueous solution consisted of Triton X-114 and nitric acid, in an on-line programmed manner. All the main parameters affecting the extraction procedure, such as oil dilution, type and concentration of surfactant and nitric acid as well as temperature and time for the emulsion breaking and phase separation, have been investigated and optimized. A mixture of oil/xylene at 10:2 proportion was found to be appropriate to use in the flow manifold. Optimum conditions were verified employing 8.0 mL of oil sample, 990 µL of extractant solution containing 10.0% m/v Triton X-114 and 10.0% v/v HNO3. Emulsion breaking and phases separation were completed at temperature 90 °C, and time 300 s. The detection and quantification limit for copper determination was found to be 5.8 µg L-1 and 19.3 µg L-1, employing aqueous standards, which are proved to produce similar performance characteristics with oil-based standards. Recovery tests were executed by appropriate additions of oil-based standard solution of copper and the recoveries ranged between 94.2 and 102.4%.

Automatic pressure-assisted dual-headspace gas-liquid microextraction. Lab-in-syringe platform for membraneless gas separation of ammonia coupled with fluorimetric sequential injection analysis.

A novel pressure-assisted dual-headspace lab-in-syringe microextraction technique is presented as an alternative approach for automatic on-line membraneless gas separation of volatile compounds. The developed gas-liquid microextraction procedure is based on the lab-in-syringe (LIS) concept by using two independent micro-syringe pumps which are connected to each other for the application of negative and positive pressure inside the common headspace area of the syringe barrels. The adoption of reduced and increased pressure conditions is facilitated by the programmable LIS strategy resulting in increased extraction rates. The analytical process includes the in-situ ammonia vapor generation in the headspace of the first microsyringe, under reduced pressure environment, and its subsequent transportation into the headspace of the second microsyringe. Then, positive pressure is applied inside the second microsyringe enabling the ammonia vapor dissolution into the extraction solution to produce a fluorescent product (isoindol-1-sulfonat). The reaction is time and temperature affected, thus after an optimized time of delay inside the thermostated syringe barrel at 60 °C, it is delivered into the flow-cell of the miniSIA system where it is quantified at 425 nm (excitation wavelength, 365 nm). The proposed preconcentration system has been fully tested and optimized regarding the relevant parameters affecting the generation of gaseous ammonia, its effective transportation into the headspace of the second syringe barrel and its quantitative dissolution and reaction with the extraction solution. For a sample volume of 3000 µL, the sample frequency is 8 h-1, the precision expressed as relative standard deviation (RSD) is 3.6 (at 5.0 µg L-1) and a detection limit (3s) of 0.05 µg L-1 for ammonium is obtained. The detection is linear in the concentration range of 0.15 and 10.0 µg L-1 with a correlation coefficient of 0.9987. The accuracy of the proposed method has been evaluated by analyzing a standard reference material (relative error: 3.8%) as well as using the Certified Method (relative error < 5.5%) for ammonium determination. The potential of this novel schema has been demonstrated for ammonia determination in natural water samples.

An automatic stirring-assisted liquid-liquid microextraction system based on lab-in-syringe platform for on-line atomic spectrometric determination of trace metals.

A novel simple fully automatic on-line magnetic stirring-assisted liquid-liquid microextraction method, based on the lab-in-syringe (LIS) concept, has been developed as an alternative approach for sample pretreatment and atomic spectrometric assays. The analytical process includes the in-syringe reaction of the metal ion with the chelating reagent, the analyte micro-extraction and the subsequent transportation of the extractant to the detection system for electrothermal atomic absorption spectrometric (ETAAS) quantification. This novel platform has been demonstrated for trace silver determination in various types of water samples. The method is linear from 19 to 450ngL-1 using a small volume of extraction solvent of 120µL. The entire procedure is accomplished within 240s resulting in a sampling frequency of 15h-1. The enhancement factor is 80, while the detection limit and the precision are 5.7ngL-1 and 3.3%, respectively. The developed method was evaluated by analyzing standard reference materials and spiked water samples with satisfactory recoveries.

Automatic On-line Solid-phase Extraction-Electrothermal Atomic Absorption Spectrometry Exploiting Sequential Injection Analysis for Trace Vanadium, Cadmium and Lead Determination in Human Urine Samples.

A fully automated sequential injection column preconcentration method for the on-line determination of trace vanadium, cadmium and lead in urine samples was successfully developed, utilizing electrothermal atomic absorption spectrometry (ETAAS). Polyamino-polycarboxylic acid chelating resin (Nobias chelate PA-1) packed into a handmade minicolumn was used as a sorbent material. Effective on-line retention of chelate complexes of analytes was achieved at pH 6.0, while the highest elution effectiveness was observed with 1.0 mol L(-1) HNO3 in the reverse phase. Several analytical parameters, like the sample acidity, concentration and volume of the eluent as well as the loading/elution flow rates, have been studied, regarding the efficiency of the method, providing appropriate conditions for the analysis of real samples. For a 4.5 mL sample volume, the sampling frequency was 27 h(-1). The detection limits were found to be 3.0, 0.06 and 2.0 ng L(-1) for V(V), Cd(II) and Pb(II), respectively, with the relative standard deviations ranging between 1.9 - 3.7%. The accuracy of the proposed method was evaluated by analyzing a certified reference material (Seronorm(TM) trace elements urine) and spiked urine samples.

An automatic countercurrent liquid-liquid micro-extraction system coupled with atomic absorption spectrometry for metal determination.

A novel and versatile automatic sequential injection countercurrent liquid-liquid microextraction (SI-CC-LLME) system coupled with atomic absorption spectrometry (FAAS) is presented for metal determination. The extraction procedure was based on the countercurrent flow of aqueous and organic phases which takes place into a newly designed lab made microextraction chamber. A noteworthy feature of the extraction chamber is that it can be utilized for organic solvents heavier or lighter than water. The proposed method was successfully demonstrated for on-line lead determination and applied in environmental water samples using an amount of 120 µL of chloroform as extractant and ammonium diethyldithiophosphate as chelating reagent. The effect of the major experimental parameters including the volume of extractant, as well as the flow rate of aqueous and organic phases were studied and optimized. Under the optimum conditions for 6 mL sample consumption an enhancement factor of 130 was obtained. The detection limit was 1.5 µg L(-1) and the precision of the method, expressed as relative standard deviation (RSD) was 2.7% at 40.0 µg L(-1) Pb(II) concentration level. The proposed method was evaluated by analyzing certified reference materials and spiked environmental water samples.

Magnetic materials as sorbents for metal/metalloid preconcentration and/or separation. A review.

The use of magnetic materials in solid phase extraction has received considerable attention in recent years taking into account many advantages arising from the inherent characteristics of magnetic particles. Magnetic solid phase extraction (MSPE) methodology overcomes problems such as column packing and phase separation, which can be easily performed by applying an external magnetic field. The use of magnetic particles in automatic systems is growing over the last few years making the on-line operation of MSPE a promising technique in the frame of green chemistry. This article aims to provide all recent progress in the research of novel magnetic materials as sorbents for metal preconcentration and determination coupled with different detection systems as well as their implementation in sequential injection and microfluidic systems. In addition, a description of preparation, characterization as well as applications of various types of magnetic materials, either with organic or inorganic coating of the magnetic core, is presented. Concluding remarks and future trends are also commented.

Pressure-driven mesofluidic platform integrating automated on-chip renewable micro-solid-phase extraction for ultrasensitive determination of waterborne inorganic mercury.

A dedicated pressure-driven mesofluidic platform incorporating on-chip sample clean-up and analyte preconcentration is herein reported for expedient determination of trace level concentrations of waterborne inorganic mercury. Capitalizing upon the Lab-on-a-Valve (LOV) concept, the mesofluidic device integrates on-chip micro-solid phase extraction (µSPE) in automatic disposable mode followed by chemical vapor generation and gas-liquid separation prior to in-line atomic fluorescence spectrometric detection. In contrast to prevailing chelating sorbents for Hg(II), bare poly(divinylbenzene-N-vinylpyrrolidone) copolymer sorptive beads were resorted to efficient uptake of Hg(II) in hydrochloric acid milieu (pH=2.3) without the need for metal derivatization nor pH adjustment of prior acidified water samples for preservation to near-neutral conditions. Experimental variables influencing the sorptive uptake and retrieval of target species and the evolvement of elemental mercury within the miniaturized integrated reaction chamber/gas-liquid separator were investigated in detail. Using merely <10 mg of sorbent, the limits of detection and quantification at the 3s(blank) and 10s(blank) levels, respectively, for a sample volume of 3 mL were 12 and 42 ng L(-1) Hg(II) with a dynamic range extending up to 5.0 µg L(-1). The proposed mesofluidic platform copes with the requirements of regulatory bodies (US-EPA, WHO, EU-Commission) for drinking water quality and surface waters that endorse maximum allowed concentrations of mercury spanning from 0.07 to 6.0 µg L(-1). Demonstrated with the analysis of aqueous samples of varying matrix complexity, the LOV approach afforded reliable results with relative recoveries of 86-107% and intermediate precision down to 9% in the renewable µSPE format.

Automated magnetic sorbent extraction based on octadecylsilane functionalized maghemite magnetic particles in a sequential injection system coupled with electrothermal atomic absorption spectrometry for metal determination.

A new automatic sequential injection (SI) system for on-line magnetic sorbent extraction coupled with electrothermal atomic absorption spectrometry (ETAAS) has been successfully developed for metal determination. In this work, we reported effective on-line immobilization of magnetic silica particles into a microcolumn by the external force of two strong neodymium iron boron (NdFeB) magnets across it, avoiding the use of frits. Octadecylsilane functionalized maghemite magnetic particles were used as sorbent material. The potentials of the system were demonstrated for trace cadmium determination in water samples. The method was based on the on-line complex formation with diethyldithiocarbamate (DDTC), retention of Cd-DDTC on the surface of the MPs and elution with isobutyl methyl ketone (IBMK). The formation mechanism of the magnetic solid phase packed column and all critical parameters (chemical, flow, graphite furnace) influencing the performance of the system were optimized and offered good analytical characteristics. For 5 mL sample volume, a detection limit of 3 ng L(-1), a relative standard deviation of 3.9% at 50 ng L(-1) level (n=11) and a linear range of 9-350 ng L(-1) were obtained. The column remained stable for more than 600 cycles keeping the cost down in routine analysis. The proposed method was evaluated by analyzing certified reference materials and natural waters.

On-line liquid phase micro-extraction based on drop-in-plug sequential injection lab-at-valve platform for metal determination.

A novel automatic on-line liquid phase micro-extraction method based on drop-in-plug sequential injection lab-at-valve (LAV) platform was proposed for metal preconcentration and determination. A flow-through micro-extraction chamber mounted at the selection valve was adopted without the need of sophisticated lab-on-valve components. Coupled to flame atomic absorption spectrometry (FAAS), the potential of this lab-at-valve scheme is demonstrated for trace lead determination in environmental and biological water samples. A hydrophobic complex of lead with ammonium pyrrolidine dithiocarbamate (APDC) was formed on-line and subsequently extracted into an 80 µL plug of chloroform. The extraction procedure was performed by forming micro-droplets of aqueous phase into the plug of the extractant. All critical parameters that affect the efficiency of the system were studied and optimized. The proposed method offered good performance characteristics and high preconcentration ratios. For 10 mL sample consumption an enhancement factor of 125 was obtained. The detection limit was 1.8 µg L(-1) and the precision expressed as relative standard deviation (RSD) at 50.0 µg L(-1) of lead was 2.9%. The proposed method was evaluated by analyzing certified reference materials and applied for lead determination in natural waters and urine samples.

Study of bond Elut® Plexa™ PCX cation exchange resin in flow injection column preconcentration system for metal determination by flame atomic absorption spectrometry.

A simple and sensitive on-line solid-phase extraction methodology for preconcentration and determination of trace amounts of Cd(II), Pd(II) and Cu(II) in natural water samples has been developed using the strong cation exchange capability of Bond Elut(®) Plexa™ PCX polymer resin. Plexa PCX is a mixed-mode sorbent, commercially available in a cartridge format and as far as we know, there is no application into the field of metal determination. The analytes were retained on the resin, eluted with 1 mol L(-1) hydrochloric acid and subsequently directed to FAAS for quantification. The influence of chemical and flow variables which affect the performance of the system have been studied, providing the appropriate conditions for the analysis of real samples. For preconcentration time of 90 s, an enrichment factor of 90, 95 and 95 and a detection limit (3 s) of 0.1, 1.8 and 0.5 µg L(-1) for Cd(II), Pb(II) and Cu(II), respectively were obtained along with a sampling frequency of 30 h(-1). The accuracy of the proposed method was evaluated by analyzing certified reference materials. This procedure was successfully applied for metal determination in environmental and biological samples.

On-line micro-volume introduction system developed for lower density than water extraction solvent and dispersive liquid-liquid microextraction coupled with flame atomic absorption spectrometry.

A simple and fast preconcentration/separation dispersive liquid-liquid micro extraction (DLLME) method for metal determination based on the use of extraction solvent with lower density than water has been developed. For this purpose a novel micro-volume introduction system was developed enabling the on-line injection of the organic solvent into flame atomic absorption spectrometry (FAAS). The effectiveness and efficiency of the proposed system were demonstrated for lead and copper preconcentration in environmental water samples using di-isobutyl ketone (DBIK) as extraction solvent. Under the optimum conditions the enhancement factor for lead and copper was 187 and 310 respectively. For a sample volume of 10 mL, the detection limit (3 s) and the relative standard deviation were 1.2 µg L(-1) and 3.3% for lead and 0.12 µg L(-1) and 2.9% for copper respectively. The developed method was evaluated by analyzing certified reference material and it was applied successfully to the analysis of environmental water samples.

Sequential injection ionic liquid dispersive liquid-liquid microextraction for thallium preconcentration and determination with flame atomic absorption spectrometry.

A novel, automatic on-line sequential injection dispersive liquid-liquid microextraction (SI-DLLME) method, based on 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF(6)]) ionic liquid as an extractant solvent was developed and demonstrated for trace thallium determination by flame atomic absorption spectrometry. The ionic liquid was on-line fully dispersed into the aqueous solution in a continuous flow format while the TlBr(4)(-) complex was easily migrated into the fine droplets of the extractant due to the huge contact area of them with the aqueous phase. Furthermore, the extractant was simply retained onto the surface of polyurethane foam packed into a microcolumn. No specific conditions like low temperature are required for extractant isolation. All analytical parameters of the proposed method were investigated and optimized. For 15 mL of sample solution, an enhancement factor of 290, a detection limit of 0.86 µg L(-1) and a precision (RSD) of 2.7% at 20.0 µg L(-1) Tl(I) concentration level, was obtained. The developed method was evaluated by analyzing certified reference materials while good recoveries from environmental and biological samples proved that present method was competitive in practical applications.

Sequential injection dispersive liquid-liquid microextraction based on fatty alcohols and poly(etheretherketone)-turnings for metal determination by flame atomic absorption spectrometry.

A novel, simple and efficient sequential injection (SI) on-line dispersive liquid-liquid microextraction (DLLME) procedure was described and was demonstrated for the assay of trace silver determination by flame atomic absorption spectrometry (FAAS). Fatty alcohols, such as 1-undecanol and 1-dodecanol, were examined as extraction solvents at microlitre volume, overcoming a major problem of the DLLME methods, the high toxicity of the extraction solvents used. Furthermore, the extractant fine droplets can be easily separated from the aqueous phase using a micro-column packed with a novel hydrophobic sorbent material, poly(etheretherketone)-turnings. In this method fine droplets of 1-dodecanol were on-line generated and dispersed into the stream of aqueous sample. By this continuous process, silver diethyldithiocarbamate (Ag-DDTC) complex was formed and extracted into the dispersed extraction solvent. No specific conditions such as ice bath for low temperature or special tools are required for extractant isolation. All significant parameters that influence the efficiency of the system such as sample acidity, concentration of complexing reagent and extraction solvent, flow-rate of disperser and sample solution as well as the preconcentration time were investigated and optimized by full factorial design. Under the optimized conditions a detection limit of 0.15 µg L(-1), a relative standard deviation (RSD) of 2.9% at 5.00 µg L(-1) Ag(I) concentration level and an enhancement factor of 186 were obtained. The developed method was evaluated by analyzing certified reference material and was applied successfully to the analysis of environmental water samples.

Development of a sequential injection dispersive liquid-liquid microextraction system for electrothermal atomic absorption spectrometry by using a hydrophobic sorbent material: determination of lead and cadmium in natural waters.

A novel on-line sequential injection (SI) dispersive liquid-liquid microextraction (DLLME) system coupled to electrothermal atomic absorption spectrometry (ETAAS) was developed for metal preconcentration in micro-scale, eliminating the laborious and time consuming procedure of phase separation with centrifugation. The potentials of the system were demonstrated for trace lead and cadmium determination in water samples. An appropriate disperser solution which contains the extraction solvent (xylene) and the chelating agent (ammonium pyrrolidine dithiocarbamate) in methanol is mixed on-line with the sample solution (aqueous phase), resulting thus, a cloudy solution, which is consisted of fine droplets of xylene, dispersed throughout the aqueous phase. Three procedures are taking place simultaneously: cloudy solution creation, analyte complex formation and extraction from aqueous phase into the fine droplets of xylene. Subsequently the droplets were retained on the hydrophobic surface of PTFE-turnings into the column. A part of 30 microL of the eluent (methyl isobutyl ketone) was injected into furnace graphite for analyte atomization and quantification. The sampling frequency was 10 h(-1), and the obtained enrichment factor was 80 for lead and 34 for cadmium. The detection limit was 10 ng L(-1) and 2 ng L(-1), while the precision expressed as relative standard deviation (RSD) was 3.8% (at 0.5 microg L(-1)) and 4.1% (at 0.03 microg L(-1)) for lead and cadmium respectively. The proposed method was evaluated by analyzing certified reference materials and was applied to the analysis of natural waters.

Poly(etheretherketone)-turnings a novel sorbent material for lead determination by flow injection flame atomic absorption spectrometry and factorial design optimization.

A novel hydrophobic sorbent material for on-line column preconcentration and separation systems coupled with atomic spectrometry was developed. Poly(etheretherketone) (PEEK) in the form of turnings was used as packing material and evaluated for trace lead determination in environmental samples. Sample and ammonium diethyl-dithiophosphate (DDPA) reagent were mixed on-line and the Pb(II)-DDPA complex was retained effectively on PEEK-turnings. Isobutyl methyl ketone (IBMK) was adopted for efficient analyte complex elution and subsequently transportation into the nebulizer-burner system for atomization. The developed sorbent material has shown, excellent chemical and mechanical resistance, fast adsorption kinetics permitting the use of high sample flow rates without significant loss of retention efficiency. For 120s sample preconcentration time the sampling frequency was 20h(-1), the enhancement factor was 110, the detection limit (3s) was c(L)=0.32microgL(-1), and the relative standard deviation (RSD) was s(R)=2.2%, at the 50.0microgL(-1) Pb(II) level. The accuracy of the developed method was evaluated by analyzing certified reference materials.

Recent developments in homogeneous and dispersive liquid-liquid extraction for inorganic elements determination. A review.

This review aims to provide an overview of homogeneous liquid-liquid extraction (HLLE) and dispersive liquid-liquid microextraction (DLLME) methods and their potential use in inorganic analysis. Relevant applications to the determination of metal ions, metalloids and organometals are included. The phase separation mechanisms of these unconventional solvent extraction techniques are discussed. The new trends in the field of miniaturization and automation are presented, while proposing future trends and potential new areas for their application.

On-line sequential injection dispersive liquid-liquid microextraction system for flame atomic absorption spectrometric determination of copper and lead in water samples.

A simple, sensitive and powerful on-line sequential injection (SI) dispersive liquid-liquid microextraction (DLLME) system was developed as an alternative approach for on-line metal preconcentration and separation, using extraction solvent at microlitre volume. The potentials of this novel schema, coupled to flame atomic absorption spectrometry (FAAS), were demonstrated for trace copper and lead determination in water samples. The stream of methanol (disperser solvent) containing 2.0% (v/v) xylene (extraction solvent) and 0.3% (m/v) ammonium diethyldithiophosphate (chelating agent) was merged on-line with the stream of sample (aqueous phase), resulting a cloudy mixture, which was consisted of fine droplets of the extraction solvent dispersed entirely into the aqueous phase. By this continuous process, metal chelating complexes were formed and extracted into the fine droplets of the extraction solvent. The hydrophobic droplets of organic phase were retained into a microcolumn packed with PTFE-turnings. A portion of 300 microL isobutylmethylketone was used for quantitative elution of the analytes, which transported directly to the nebulizer of FAAS. All the critical parameters of the system such as type of extraction solvent, flow-rate of disperser and sample, extraction time as well as the chemical parameters were studied. Under the optimum conditions the enhancement factor for copper and lead was 560 and 265, respectively. For copper, the detection limit and the precision (R.S.D.) were 0.04 microg L(-1) and 2.1% at 2.0 microg L(-1) Cu(II), respectively, while for lead were 0.54 microg L(-1) and 1.9% at 30.0 microg L(-1) Pb(II), respectively. The developed method was evaluated by analyzing certified reference material and applied successfully to the analysis of environmental water samples.

Flow injection on-line displacement/solid phase extraction system coupled with flame atomic absorption spectrometry for selective trace silver determination in water samples.

A novel flow injection (FI) on-line displacement solid phase extraction preconcentration and/or separation method coupled with FAAS in order to minimize interference from other metals was developed for trace silver determination. The proposed method involved the on-line formation and subsequently pre-sorption of lead diethyldithiocarbamate (Pb-DDTC) into a column packed with PTFE-turnings. The preconcentration and/or separation of the Ag(I) took place through a displacement reaction between Ag(I) and Pb(II) of the pre-sorbed Pb-DDTC. Finally, the retained analyte was eluted with isobutyl methyl ketone (IBMK) and delivered directly to nebulizer for measuring. Interference from co-existing ions with lower DDTC complex stability in comparison with Pb-DDTC, was eliminated without need for any masking reagent. With 120 s of preconcentration time at a sample flow rate of 7.6 mL min(-1), an enhancement factor of 110 and a detection limit (3s) of 0.2 microg L(-1) were obtained. The precision (RSD, n=10) was 3.1% at the 10 mug L(-1) level. The developed method was successfully applied to trace silver determination in a variety of environmental water samples and certified reference material.