Vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction for the determination of triazine herbicides in water samples by microemulsion electrokinetic chromatography

A novel method based on the combination of microemulsion electrokinetic chromatography (MEEKC) and vortex‐assisted surfactant‐enhanced‐emulsification liquid–liquid microextraction (VSLLME) was developed for the determination of five triazine herbicides (simazine, atrazine, ametryn, prometryn, and terbutryn) in water samples. The five triazine herbicides were baseline separated by using the microemulsion buffer containing a 10 mmol/L borate buffer at pH 9.5, 2.5% (w/v) SDS as surfactant, 0.8% (w/v) ethyl acetate as oil phase, and 6.0% (w/v) 1‐butanol as cosurfactant. The optimum extraction conditions of VSLLME were as follows: 100 μL chloroform was used as extraction solvent, 5.0 × 10^?5 mol/L Tween‐20 was chosen as the surfactant to enhance the emulsification, and the extraction process was carried out by vortex mixing for 3 min. Under these optimum experimental conditions, the calibration curve was linear in the range of 2.0–200.0 ng/mL, with the correlation coefficients (r²) varying from 0.9927 to 0.9958. The detection limits of the method varied from 0.41 to 0.62 ng/mL. The purposed method was applied to the determination of five triazine herbicides in real water samples, and the recoveries were between 80.6 and 107.3%.     

Application of ultrasound-assisted emulsification microextraction for the determination of triazine herbicides in soil samples by high performance liquid chromatography

Ultrasound-assisted emulsification microextraction was applied to extract the herbicides simazine, atrazine, prometon, ametryn and prometryn from soil samples. They then were determined by HPLC with diode-array detection. Parameters that affect the extraction efficiency, such as the kind and volume of the extraction solvent, emulsification time and addition of salt, were optimized. Under the optimum conditions, the following analytical figures of merits are found: enrichment factors between 145 and 222, limits of detection between 0.1 to 0.5 ng g^?1, analytical linearity in the range from 1.0 to 200 ng g^?1, correlation coefficients (r) between 0.9989 and 0.9998, relative standard deviations from 2.8% to 3.6% (at n?=?5, intraday) and 3.7% to 4.3% (interday), and recoveries (at spiking levels of 5.0 and 50.0 ng g^?1) from 82.6% to 92.0%. The technique is simple, practical, rapid, and environmentally friendly.     

Determination of triazine herbicides in human body fluids by solid-phase microextraction and capillary gas chromatography

Summary Eight triazine herbicides, prometon, propazine, atrazine, simazine, prometryn, ametryn, metribuzin, and cyanazine, have been extracted from human whole blood and urine samples by headspace solid-phase microextraction (SPME) with a polydimethylsiloxane-coated fiber and quantified by capillary gas chromatography with nitrogen-phosphorus detection. Extraction efficiencies for all compounds were 0.21–0.99% for whole blood, except for cyanazine (0.06%). For urine, the extraction efficiencies for prometon, propazine, atrazine, prometryn and ametryn were 13.6–38.1%, and those of simazine, metribuzin and cyanazine were 1.35–8.73%. The regression equations for the compounds extracted from whole blood were linear within the concentration ranged 0.01–1 μg (0.5 mL)⁻¹ for prometon, propazine, atrazine, prometryn, and ametryn, and 0.02–1 μg (0.5 mL)⁻¹ for simazine, metribuzin, and cyanazine. For urine, regression equations for all compounds were linear within the concentration range 0.005–0.25 μg mL⁻¹. Compound detection limits were 2.8–9.0 ng (0.5 mL)⁻¹ and 0.4–2.0 ng mL⁻¹ for whole blood and urine, respectively. The coefficients of within-day and day-to-day variation were satisfactory for all the compounds, and not greater than 10.3 and 14.2%, respectively. Data obtained from determination of atrazine in rat whole blood after oral administration of the compound are also presented.     

Determination of Simazine and Atrazine in River Water by Cloud-Point Extraction and High-Performance Liquid Chromatography

Atrazine and simazine are endocrine-disrupting herbicides that may be transported to surface water, unbalancing ecosystems. Sensitive and low-cost methods are required for monitoring the residues of these compounds. Although several highly sensitive chromatographic methods coupled to tandem mass spectrometry are available, these methods use high-cost instrumentation. Ultraviolet detection usually does not provide the sensitivity and selectivity for monitoring these herbicide residues at the maximum concentrations levels permitted by regulatory agencies, so that extraction and concentration steps are required. Cloud-point extraction in Triton X-114 micelles was investigated to extract and preconcentrate atrazine and simazine. Treatment of 10?mL of sample solutions with 5?mL of 5% (m v^?1) Triton X-114 in the presence of NaCl (0.3?g) with heating at 60°C for 30?min led to phase separation and the transfer of herbicides to the surfactant-rich phase, which was dissolved in 90:10 methanol:water for liquid chromatography analysis with ultraviolet detection. The linear dynamic range was 1–50?µg?L^?1 for the herbicides. The limits of detection were 0.13 and 0.27?µg?L^?1 for simazine and atrazine, respectively. The methodology was applied to water samples fortified with 1, 5, 15, and 50?µg?L^?1 of the analytes, resulting in recoveries between 86 and 132% with relative standard deviations less than 6%. The method is low cost and uses small volumes of toxic solvents with useful application in trial studies.     

Application of liquid phase microextraction based on solidification of floating organic drop for the determination of triazine herbicides in soil samples by gas chromatography with flame photometric detection

A simple and efficient liquid phase microextraction based on solidification of floating organic drop coupled with gas chromatography–flame photometric detection was developed for the extraction and determination of some triazine herbicides (metribuzin, simetryn, ametryn and prometryn) in soil samples. The type and volume of the extraction solvent, sample solution temperature, salt addition, stirring rate, and the extraction time were optimized. Under the optimal conditions, the linear response was observed over the range of 10–2000?µg?kg^?1 for metribuzin and 2–500?µg?kg^?1 for simetryn, ametryn, and prometryn, respectively, with the correlation coefficients (r) varying from 0.9990 to 0.9992. The limits of detection were in the range between 0.2 and 1.0?µg?kg^?1 (S/N?=?3?:?1). The recoveries of the target analytes for the spiked soil samples ranged from 75.5% to 97.3%, with the relative standard deviation values less than 7.2% (n?=?5). The enrichment factors were achieved ranging from 122 to 336. The developed method was applied for the preconcentration and determination of triazine herbicides in real soil samples and a satisfactory result was obtained.     

Application of bamboo charcoal as solid-phase extraction adsorbent for the determination of atrazine and simazine in environmental water samples by high-performance liquid chromatography-ultraviolet detector

In this article, a new method for the determination of triazine herbicides atrazine and simazine in environment aqueous samples was developed. It was based on solid-phase extraction (SPE) using bamboo charcoal as adsorbent and high-performance liquid chromatography-ultraviolet detector (HPLC-UV) for the enrichment and determination of atrazine and simazine at trace level. Related important factors influencing the extraction efficiency, such as the kind of eluent and its volume, flow rate of the sample, pH of the sample, and volume of the sample, were investigated and optimized in detail. Under the optimal conditions, the experimental results showed that excellent linearity was obtained over the range of 0.5–30 μg L⁻¹ with correlation coefficients 0.9991 and 0.9982, for atrazine and simazine, respectively; and the relative standard deviations of two analytes were 8.3, 8.7%, respectively. The proposed method was successfully applied to the analysis of tap water and well water samples. And satisfactory spiked recoveries were obtained in the range of 75.2–107.1%. The above results indicated that the developed method was an excellent alternative for the routine analysis in environmental field.     

Quantification and confirmation of priority organic micropollutants in water by LC-tandem mass spectrometry

Liquid chromatography coupled to tandem mass spectrometry with a triple quadrupole analyser was used to determine selected (medium) polar organic pollutants—isoproturon, diuron and pentachlorophenol, as the herbicides simazine, atrazine, terbuthilazine, alachlor, and metolachlor—in treated water from urban solid-waste leachates. Two millilitres of water was preconcentrated by on-line trace enrichment (solid-phase extraction liquid chromatography) which allowed rapid analysis, but still with a satisfactory sensitivity, as the limits of quantification were 0.05?µg?L^?1, while the limits of detection were in the range of 0.001–0.01?µg?L^?1. Confirmation of the identity of compounds was ensured by the use of two tandem mass spectrometry transitions. Moreover, a study of matrix effects was thoroughly investigated by applying the developed procedure to different ground and surface waters. A simple dilution of the water sample with high-performance-liquid-chromatography-grade water was sufficient to minimize and/or remove this undesirable effect in all water samples tested, this approach being feasible due to the excellent sensitivity of the method.     

Simultaneous Filtration and Solid-Phase Extraction Combined with Large-Volume Injection in GC/MS for Ultra-Trace Analysis of Polar Pesticides in Surface Water

A method combining simultaneous filtration and solid-phase extraction (SPE) with large-volume injection (LVI) in gas chromatography/mass spectrometry (GC/MS) was developed to determine 13 polar pesticides in surface water. The selected pesticides - 4 organophosphorus, 7 organonitrogens and 2 triazine degradation products - were extracted from 0.5-L samples of filtered and raw water using cartridges filled with a silica-bonded material (1 g of ISOLUTE triazine, C-18) and a depth filter. No obstruction was observed during the extraction of raw water drawn from the St. Lawrence River (concentration of suspended particulate matter (SPM) ranging from 2 to 58 mg L^?1). Overall percent recoveries were satisfactory for all the target pesticides (>60%) except desisopropyl-atrazine (more polar), which varied from 29 to 46% according to sample pH. The coefficient of variation was below 10% for the majority of the target pesticides and detection limits ranged from 0.1 to 0.8 ng L^?1. Applied to real samples drawn from the St. Lawrence River, this method allowed for the detection of atrazine, cyanazine, desethyl-atrazine (DEA), desisopropyl-atrazine (DIA), metolachlor and simazine, at concentrations of 6 to 91 ng L^?1. Using atrazine and metolachlor as examples, the correlation between filtered and raw water samples was more significant for the former (r = 0.87) than for the latter (r = 0.67). Temporal variations in atrazine and metolachlor in filtered water drawn from the St. Lawrence River, for example, were similar whether using the established method, based on liquid-liquid large-volume extraction (LVE) combined with GC/NPD analysis, or the one proposed herein. The latter method, however, systematically found atrazine concentrations 62% higher than those obtained by the older one, applied to the same field samples. Thus, the switch to the new analytical method will require the application of a correction factor to the atrazine concentration time series acquired with the previously used method.     

Self‐assembled magnetic nanoparticle supported zeolitic imidazolate framework‐8: An efficient adsorbent for the enrichment of triazine herbicides from fruit,vegetables, and water

Zeolitic imidazolate frameworks have positive surface charges and high adsorption capabilities. In this work, zeolitic imidazolate frameworks‐8 and negatively charged magnetic nanoparticles were self‐assembled by electrostatic attraction under sonication. The extraction performance of the synthesized hybrid material was evaluated by using it as a magnetic adsorbent for the enrichment of triazine herbicides in various sample matrices prior to analysis using ultrafast liquid chromatography. The main parameters, that is, extraction time, adsorbent dosage, salt concentration, and desorption conditions, were evaluated. Under the optimum conditions, good linear responses from 2.5 to 200 ng/mL for atrazine (simazine) and 1 to 200 ng/mL for prometryn (ametryn), with correlation coefficients (R ²) higher than 0.9992 were obtained. The detection limits of the method (S/N = 3) were 0.18–0.72 ng/mL. The proposed method was successfully used to determine triazine herbicides in six samples, namely, apple, pear, strawberry, pakchoi, lettuce, and water. The amounts of simazine in all the fruit and vegetable samples were 10.8–25.2 ng/mL. The recoveries of all the analytes were 88.0–101.9%, with relative standard deviations of less than 8.8%.     

Improving the Detectability of Sequential Injection Chromatography (SIC): Determination of Triazines by Exploiting Liquid Core Waveguide (LCW) Detection

Coupling a liquid core waveguide cell to a sequential injection chromatograph improved the detection limits for determination of triazine herbicides without compromising peak resolution. Separation of simazine, atrazine, and propazine was achieved in water samples by a 25 mm long C₁₈ monolithic column. Detection was made at 238 nm using a type II LCW (silica capillary coated with Teflon® AF2400) cell with 100 cm of optical path length. Detection limits for simazine, atrazine, and propazine were 2.3, 1.9, and 4.5 µg L^?1, respectively. Reduced analysis time and low solvent consumption are other remarkable features of the proposed method.     

Determination of atrazine and simazine in environmental water samples using multiwalled carbon nanotubes as the adsorbents for preconcentration prior to high performance liquid chromatography with diode array detector

Multiwalled carbon nanotubes, a new nanoscale material, has been gained many interests for use in various fields, and has exhibited exceptional merit as SPE absorbents for enrichment of environmental pollutants. This paper focused on the enriching power of atrazine and simazine, two important widely used triazine herbicides and described a novel and sensitive method for determination of these two herbicides based on SPE using multiwalled carbon nanotubes as solid phase absorbents followed by high performance liquid chromatography with diode array detector. Factors that maybe affect the enrichment efficiency of multiwalled carbon nanotubes such as the volume of eluent, sample flow rate, sample pH, and volume of the water samples were optimized. Under the optimal procedures, multiwalled carbon nanotubes as the absorbents have obtained excellent enrichment efficiency for atrazine and simazine. The detection limits of the atrazine and simazine were 33 and 9 ng l⁻¹, respectively. The spiked recoveries of the two analytes were over the range of 82.6-103.7% in most cases. Good analytical performance was achieved from real-world water samples such as river water, reservoir water, tap water and wastewater after primary pretreatment with proposed method. All these experimental results indicated that the developed method could be used as an alternative for the routine analysis of atrazine and simazine in many real water samples.     

Determination and risk assessment of pesticide residues in lake Amvrakia (W. Greece) after agricultural land use changes in the lake's drainage basin

A monitoring study of pesticides belonging to different chemical families was carried out in Amvrakia lake (West Greece) waters after land use changes in the lake's basin. Based on land-use patterns, nine sampling points were selected. Pesticides were extracted by solid phase extraction (SPE) using Oasis HLB cartridges and analysed by gas chromatographic techniques with flame thermionic and mass-spectra detection. Pesticides detected during the monitoring survey include eight herbicides (alachlor, atrazine, s-metolachlor, pendimethalin, prometryne, propachlor, simazine, trifluralin) and one metabolite (deethyl atrazine) with concentration levels up to 807?ng?L^?1 (recorded for alachlor), eight insecticides (azinphos methyl, chlorpyrifos, chlorpyrifos methyl, diazinon, dimethoate, fenitrothion, malathion, methidathion) with concentration levels up to 490?ng?L^?1 (recorded for azinphos methyl) and six fungicides (benalaxyl, cyproconazole, fenarimol, pyrimethanil, triadimefon, triadimenol) with concentration levels up to 408?ng?L^?1 (recorded for pyrimethanil). More frequently detected pesticides were atrazine, deethyl atrazine, alachlor, azinphos methyl, chlorpyrifos methyl, diazinon and pyrimethanil. The higher concentrations were measured during spring-early summer period, following seasonal application of pesticides and diminished significantly during winter. Littoral sampling stations presented higher pesticide concentration levels and more frequent detection. Aquatic risk assessment was based on the Risk Quotient (RQ?=?MEC/PNEC) deterministic method regarding three trophic levels: algae, aquatic invertebrates and fish. Non-acceptable risk for 10 compounds was observed when maximum concentrations were used. Compliance to EC environmental quality standards is also discussed.     

Determination of Atrazine,Simazine, Alachlor,and Metolachlor in Surface Water Using Dispersive Pipette Extraction and Gas Chromatography–Mass Spectrometry

Four commonly found pesticides (alachlor, atrazine, metolachlor, and simazine) in surface water were determined using dispersive pipette extraction followed by gas chromatography–mass spectrometry. The rapid mixing and equilibrium between the dispersive pipette extraction adsorbent and water sample resulted in fast and efficient extraction. Using only 5?mL of water sample, the estimated time consumption for extraction of each sample was less than 5?min. Method validation was performed to evaluate accuracy, precision, linearity, the limits of detection, and the limits of quantitation. Average recovery of above 90% was obtained with relative standard deviations below 10%, which indicated good accuracy and precision of the dispersive pipette extraction method. Coefficients of determination were all above 0.9901 and showed good linearity. For the four pesticides studied using the current method, the limits of detection ranged from 7 to 40?ng?L^?1, and limits of quantitation were from 20 to 130?ng?L^?1. Method validation results supported the application of the current method for drinking water safety monitoring per National Primary Drinking Water Regulations established by the US Environmental Protection Agency. Water samples from Lake Lanier and Stone Mountain Lake (Georgia, USS) were analyzed with this method as a preliminary work for a larger scale drinking water quality study in the future. Trace amounts of simazine and atrazine were found in lake water samples, but both were below the regulation levels of the US Environmental Protection Agency.     

Determination of Triazines and N-Methylcarbamate Pesticides in Water by High-Performance Liquid Chromatography-Diode Array Detection

A rapid and selective method for the simultaneous determination of triazine herbicides (atrazine, its degradation product desethylatrazine, simazine, prometryn, terbutryn) and N-methylcarbamate insecticides (propoxur, carbaryl and methiocarb) in surface water has been developed. A 0.5 L of the water sample was preconcentrated by passage through a 1 g C₁₈ solid-phase extraction cartridge. The retained compounds were eluted with 5 mL of methanol from the cartridge. The pesticides were separated and quantified by reversed-phase high-performance liquid chromatography with UV diode-array detection. Analytical separation was performed using a concave gradient elution with acetonitrile and water on a C₁₈ column. Prometryn and terbutryn were determined at 240 nm; propoxur, methiocarb at 204 nm and the others at 220 nm. Recoveries varied from 85 to 102% over concentrations at 0.025 and 0.2 µg L^?1. The limits of detection for the compounds investigated are in the range of 0.005-0.012 µg L^?1.     

Preparation and binding study of solid-phase microextraction fiber on the basis of ametryn-imprinted polymer: Application to the selective extraction of persistent triazine herbicides in tap water,rice, maize and onion

A monolithic ametryn molecular-imprinted polymer based on a simple polymerization method was fabricated for use as new solid-phase microextraction (SPME) fiber, which can be coupled with GC and GC/MS for selective extraction and analysis of triazine herbicides. Methacrylic acid (MAA), ethylene glycol dimethacrylate (EDMA) and ametryn bear role of functional monomer, cross-linker and template, respectively. In the optimized conditions the fabricated fiber showed better molecular recognition abilities for methylthiotriazine herbicides than chloro-triazine herbicides. By use of bi-Langmuir isotherm model the evaluated equilibrium constants for ametryn were 0.01 and 890.69 μM⁻¹, and the numbers of binding sites were 129.98 and 5.82 nmol g⁻¹, respectively. The high extraction efficiency was obtained for ametryn, prometryn, terbutryn, atrazine, simazine, propazine, and cyanazine, yielding the detection limits of 14, 28, 45, 56, 85, 95 and 74 ng mL⁻¹, respectively by GC with flame ionization detection. The reliability of the prepared fiber for extraction of ametryn and other analogues in real samples has been investigated and proved by using spiked samples such as tap water, rice, maize, and onion.     

Preconcentration of atrazine and simazine with multiwalled carbon nanotubes as solid-phase extraction disk

A sensitive and selective preconcentration method using solid-phase extraction (SPE) disk, namely multiwalled carbon nanotubes (MWCNTs) disk, is proposed for the determination of atrazine and simazine in water samples. Atrazine and simazine were extracted on MWCNTs disk and then determined by gas chromatography–mass spectrometry (GC/MS). Several parameters on the enrichment factor of the analytes were investigated. The experimental results showed that it was possible to obtain quantitative analysis when the solution pH was 5 using 200 mL of validation solution containing 0.1 μg of triazines and 5 mL of acetone as an eluent. The maximum enrichment factors for atrazine and simazine were 3900 ± 250 and 4000 ± 110, respectively when 200 mL of sample solution volume was used. Relative standard deviations for seven determinations were 6.9% (atrazine) and 3.0% (simazine) under optimum conditions. The linear range of calibration curves were 0.1 to 1 ng mL^{− 1} for each analyte with good correlation coefficients. The detection limits (3S/N) were 2.5 and 5.0 pg mL^{− 1} for atrazine and simazine, respectively. The proposed method was successfully applied to the determination of atrazine and simazine in environmental water samples with high precision and accuracy.     

A simple method for simultaneous determination of nine triazines in drinking water

A simple, effective, and economic method for determination of nine triazines (ametryn, atrazine, cyanazine, prometryn, propazine, simazine, simetryn, terbuthylazine, and terbutryn) in drinking water based on solid-phase extraction (SPE) followed by high-performance liquid chromatography-diode array detection (HPLC-DAD) was developed. A specialized solid phase (Oasis HLB) was used, and the parameters that may affect the efficiency of SPE were optimized. The limits of detection (ranged from 0.010 to 0.023 µg L^?1) were satisfactory and allow the determination of triazines at the levels required by European Union legislation. Repeatability (2.4–7.6%) and intermediate precision (0.9–11.0%) calculated at 0.1 µg L^?1 (legislation level) were adequate. The accuracy calculated as the average recovery of spiked tap and mineral waters was higher than 86% for all compounds. The developed method also could be used for undergraduate laboratory experiments because it acquaints students with solution preparation, solid phase extraction procedure, and HPLC-DAD technique.     

Sorption and Preconcentration of the Herbicides Atrazine,Simazine, and Ametryne on Montmorillonite

This paper describes the treatment of montmorillonite (MT), with K⁺ (MT_K), Na⁺ (MT_Na), and Ca²⁺ (MT_Ca) to explore the use of these minerals for the extraction and preconcentration of the herbicides atrazine, simazine, and ametryne from aqueous medium. In the sorption process, the three materials exhibited good performance; ametryne was totally sorbed. For atrazine and simazine, MT_K showed a removal between 90% (atrazine) and higher than 99% (simazine). The recoveries employing solutions at initial concentrations of 100 µg L^?1 of each herbicide showed results of 90% (simazine) and 94% (atrazine), whereas for 10 µg L^?1, the results of 73% (simazine) and 81% (atrazine) were obtained. On the other hand, ametryne showed poor recovery values (25 to 40%), probably due to a stronger interaction with MT_K, lowering the recovery values. Based on the results for atrazine and simazine, MT_K presented good features to be used as sorbent phase and for preconcentration, being easily prepared with low cost, demanding low amounts to be used for this purpose, providing fast sorption of atrazine and simazine, and with appropriate recoveries.     

Determination of Triazine Herbicides and Metabolites by Solid Phase Extraction with HPLC Analysis

An efficient solid phase extractive preconcentration/separation method was developed for the trace determination of herbicides in aqueous samples using Amberlite XAD-4 resin as the adsorbent. The retained herbicides were eluted with methanol at a flow rate of 1.0 mL min^?1 and determined by HPLC-DAD (wavelength of 220 nm) using water (pH:4.7, phosphoric acid) and methanol (ratio 35:65) as the mobile phase with a flow rate of 1.0 mL min^?1. Quantitative recoveries of simazine, atrazine and its metabolities were achieved at optimized analysis conditions that included 0.75 g of resin; a pH of 3.0; an eluent volume of 3.0 mL; an eluent flow rate of 1.0 mL min^?1; and a sample flow rate of 4.0 mL min^?1. The limits of detection, preconcentration factor, and linear ranges for the herbicides were 0.084–0.121 µgL^?1, 1000, and 0.5–20 mg L^?1, respectively. The performance of the method was evaluated by analysis of spiked water samples. The recoveries of simazine, atrazine and their metabolities were found to be quantitative (99.6–104.8%) with RSDs of 2.2–4.8% and 2.8–4.7% for intra-day and inter-day precision, respectively. The proposed method was successfully applied for trace determination of studied analytes in waste water, apple juice, and red wine samples.     

Preconcentration of atrazine and simazine with multiwalled carbon nanotubes as solid-phase extraction disk

A sensitive and selective preconcentration method using solid-phase extraction (SPE) disk, namely multiwalled carbon nanotubes (MWCNTs) disk, is proposed for the determination of atrazine and simazine in water samples. Atrazine and simazine were extracted on MWCNTs disk and then determined by gas chromatography–mass spectrometry (GC/MS). Several parameters on the enrichment factor of the analytes were investigated. The experimental results showed that it was possible to obtain quantitative analysis when the solution pH was 5 using 200 mL of validation solution containing 0.1 μg of triazines and 5 mL of acetone as an eluent. The maximum enrichment factors for atrazine and simazine were 3900 ± 250 and 4000 ± 110, respectively when 200 mL of sample solution volume was used. Relative standard deviations for seven determinations were 6.9% (atrazine) and 3.0% (simazine) under optimum conditions. The linear range of calibration curves were 0.1 to 1 ng mL^− 1 for each analyte with good correlation coefficients. The detection limits (3S/N) were 2.5 and 5.0 pg mL^− 1 for atrazine and simazine, respectively. The proposed method was successfully applied to the determination of atrazine and simazine in environmental water samples with high precision and accuracy.