Triazine Herbicides In Water Research Articles

Screening triazine herbicides in drinking water in the Yangtze River Delta, China: Occurrence and health risk

Triazine herbicides are toxic to humans and aquatic organisms. Current research on triazine herbicides in water has been focused on atrazine and has largely ignored the potential risks of other herbicides, particularly in drinking water. In this study, the drinking water of the Yangtze River Delta region was tested for 13 triazine herbicides using high-throughput organic analysis testing combined with high volume solid-phase extraction, and 11 of these herbicides were detected in tap water (TW) (mean: 5.29 ± 6.1 ng/L). Terbutryn had the highest percentage in TW, which may be related to the treatment process of water treatment plants. Nine triazine herbicides were detected in barreled water (BW) (mean: 1.67 ± 0.538 ng/L). The concentrations of most triazine herbicides were higher in TW than in BW. Water source quality significantly impacted the distribution of triazine herbicides in BW, with deep treatment reducing the content of some pesticide residues. The difference in herbicide types in drinking water was primarily influenced by both the water treatment process and the source water. There were no significant differences between urban and suburban areas, with larger differences between cities. Triazine herbicides were ingested more through TW, with an estimated daily intake 3–4 times higher (range: 0.018–0.05 ng/kg-bw/d) than BW (range: 0.006–0.016 ng/kg-bw/d). The acute toxicities of the two groups of drinking water samples were negligible. This study provides the first overview of the occurrence, regional distribution characteristics, and associated potential human health risks of triazine herbicides in drinking water in China.

Hydroxyl group-enriched microporous organic network for high-performance solid-phase extraction of triazine herbicides: Experiment and DFT calculation on adsorption behavior

High-efficiency monitoring of triazine herbicides residues is vital in the evaluation of environmental and agro-food safety. Herein, we fabricated a spherical hydroxylated microporous organic network (OH–MON) with high surface area, high stability and rich hydrogen-bonding affinity sites suitable as an advanced solid-phase extraction (SPE) adsorbent for efficient adsorption of triazine herbicides. Density–functional theory calculations and competitive enrichment tests confirmed that hydrogen bonding played a vital role to the enrichment of triazine herbicides by OH–MON. This OH–MON SPE cartridge showed satisfactory reproducibility, maintaining its adsorption capacity after 10 adsorption–desorption cycles. Furthermore, we developed a sensitive analytical approach for determining triazine herbicides residues in water and fruit juice samples. Desirable linear correlations within 0.50–250 ng⋅L-1, an ultra-low detection limit (0.03–0.15 ng⋅L-1 for water; 0.04–0.21 ng⋅L-1 for fruit juice), good precision and high enrichment factor for triazine herbicides were achieved. A preliminary practical application of the developed method was proved by the efficient detection of triazine herbicides in water and fruit samples with good recoveries (72.8%−100.4% and 72.0%−97.7% for water and juice samples, respectively). This study serves as a good reference for designing the high-functionalized MON to capture contaminants and address environmental and agro-food safety issues.

Polypyrrole monolithic extraction phase: From conventional to miniaturized sample preparation techniques

Monolithic polymers are described as continuous and highly porous materials. They have been gaining popularity as an effective extracting phase for some sample preparation methods, due to their variety of functionalities, such as wide pH range tolerance, good permeability, and its ability to allow changes into their surface. Polypyrrole represents an interesting alternative for the modification in extraction phases due to its well related ability to perform multiple interactions, such as acid-base, π - π, ion exchange, interactions with hydrophobic affinities or polar functional groups. Among the different sample preparation techniques, solid-phase extraction (SPE) is one of the most popular and used; a miniaturized version of SPE is the disposable pipette extraction (DPX). DPX is a recent miniaturized extraction technique that usually employing silica-based sorbents inside a pipette tip (5 or 1 mL). The present study proposes the development of a monolithic extraction phase composed by styrene divinylbenzene (1:1) modified with polypyrrole for SPE and DPX techniques. The efficiency of the material was evaluated in face of the extraction of different samples and analytes, triazine herbicides in water and dexamethasone in synthetic synovial liquid by conventional and miniaturized solid-phase extraction techniques. The extractions performed by SPE and DPX presented absolute recovery values ranging from 74.8 to 105.0%, inter-day precision ranging from 0.6 to 14.0%, and limit of quantification of 0.5 and 5.0 ng.mL−1, respectively. The DPX miniaturized method exhibited results equivalent to the methods reported in the literature for extraction of dexamethasone in synovial fluid samples. Moreover, this technique proved to be quicker and cheaper than SPE, and produced fewer residual volumes, supporting the preference for green chemistry. Monolithic polymers modified with polypyrrole presented to be a feasible alternative extraction phase for miniaturized sample preparation techniques.

Method development and application for triazine herbicides analysis in water, soil and sediment samples from KwaZulu-Natal

This study reports on the development and application of solid phase extraction (SPE) and ultrasonic extraction (UE) methods for the analysis of triazine herbicides in water, soil and sediment samples. The extraction parameters such as conditioning solvent, sample loading volume, eluting solvent, extraction time and sample mass were optimized due to their influence on the extraction efficiency of the analytes. To assess the applicability of the SPE and UE methods, spiked distilled water or soil samples were extracted and analyzed using an LC-PDA instrument. The recoveries obtained under optimum conditions were between 65–94% and 75–100% for SPE and UE, respectively. The relative standard deviations obtained were less than 0.36% for SPE and less than 4.6% for UE. The limit of detection (LOD) ranged from 0.026–0.084 µg/L for SPE and 0.0028–0.0083 mg/kg for UE. The limit of quantification (LOQ) was between 0.088–0.28 µg/L for SPE and 0.0089–0.028 mg/kg for UE. The concentrations of triazines were found to be between 0.96–7.4 µg/L and 0.79–15 µg/L in river water and wastewater effluent samples, respectively. In sediment samples, the triazine concentrations were found to be between 0.032–0.93 mg/kg, while in soil samples they were between 0.12–1.03 mg/kg.

Coupling of multi-walled carbon nanotubes/polydimethylsiloxane coated stir bar sorptive extraction with pulse glow discharge-ion mobility spectrometry for analysis of triazine herbicides in water and soil samples

An analytical method based on stir bar sorptive extraction (SBSE) coupled with pulse glow discharge-ion mobility spectrometry (PGD-IMS) was developed for analysis of three triazine pesticide residues in water and soil samples. An injection port with sealing device and stir bars hold device were designed and constructed to directly position the SBSE fiber including the extracted samples into the heating device, making desorption and detection of analytes proceeded simultaneously. The extraction conditions such as SBSE solid phase material, extraction time, extraction temperature, pH value and salt concentration were optimized. Mixture of MWCNTs-COOH and PDMS were shown to be effective in enriching the triazines. The LODs and LOQs of three triazines were found to be 0.006–0.015μgkg−1 and 0.02–0.05μgkg−1, and the linear range was 0.05–10μgL−1 with determination coefficients from 0.9987 to 0.9993. The SBSE-PGD-IMS method was environmentally friendly without organic solvent consumption in the entire experimental procedures, and it was demonstrated to be a commendable rapid analysis technique for analysis of triazine pesticide residues in environmental samples on site. The proposed method was applied for the analysis of real ground water, surface water and soil samples.

Graphene oxide based in‐tube solid‐phase microextraction combined with liquid chromatography tandem mass spectrometry for the determination of triazine herbicides in water

J. Sep. Sci. 2015, 38, 2312–2319. DOI: 10.1002/jssc.201500070 Monolayer graphene oxide sheets were covalently modified onto the inner wall of a fusedsilica capillary to prepare a graphene oxide coating with 30 nm thickness and porous wrinkled-membrane-like structure, which was used as an extraction column for in-tube solid phase microextraction. The coating showed enough stability and high extraction efficiency to triazine compounds due to π-π stacking and hydrogen bonding interactions between graphene oxide and triazine molecules. The proposed in-tube solid phase microextraction method was applied to simultaneous analysis of trace triazine herbicides in environmental samples, with good recoveries and repeatability.

Graphene oxide based in-tube solid-phase microextraction combined with liquid chromatography tandem mass spectrometry for the determination of triazine herbicides in water.

A novel in-tube solid-phase microextraction method based on a graphene oxide coated column was developed for the determination of triazines in waters. This column was prepared by the covalent modification of monolayer graphene oxide sheets onto the inner wall of a fused-silica capillary. Scanning electron microscopy showed that the thickness of the graphene oxide coating was ∼30 nm, with a porous, wrinkled membrane-like structure. Its performance was evaluated through the extraction of triazines in water. Results showed that the coating was stable for at least 100 replicate extractions, and variety of multi-columns was less than 10%. Flow rate, loading volume, pH, and ionic strength of samples played an important effect on the extraction. The high extraction efficiency was mainly attributed to π-π stacking and hydrogen bonding interactions. The in-tube solid-phase microextraction was used in the determination of triazines with liquid chromatography and tandem mass spectrometry, and the detection limits were 0.0005-0.005 μg/L for five triazine compounds. Further, the method was applied to the analysis of triazine herbicides in real samples including tap water, sea water, and river water, and the recoveries were 82.8-112.0, 85.4-110.5, and 81.6-105.9%, respectively, with RSDs of 2.7-7.1%.

Effervescence assisted on-site liquid phase microextraction for the determination of five triazine herbicides in water

A novel effervescence assisted on-site liquid phase microextraction has been developed for the determination of five triazine herbicides in water. The use of an effervescent tablet composed of citric acid, sodium bicarbonate and 1-undecanol (extraction solvent) was the core of the method. The triazine herbicides in water were extracted by 1-undecanol released from tablet under effervescence and determined by ultra-high pressure liquid chromatography tandem mass spectrometer. The experimental variables, including NaCl concentration, temperature, weight of effervescent tablet, volume of extraction solvent and pH value, were screened by a Plackett–Burman design and optimized by a Box–Behnken design. Under the optimized conditions, good linearity was obtained in the range of 0.05–10μgL−1 with correlation coefficients ranging from 0.9936 to 0.9988. The limits of quantification were between 7.6 and 26.4ngL−1, and the recoveries were in 71.4–93.2% with relative standard deviations of 2.5–10.9%. This method, which does not require centrifugation and any special apparatus, was successfully applied to determine triazine herbicides in real waters, promising to be a way to speed field sampling procedures for the organic pollutants monitoring in water.

Online coupling of in-tube solid-phase microextraction with direct analysis in real time mass spectrometry for rapid determination of triazine herbicides in water using carbon-nanotubes-incorporated polymer monolith.

Online coupling of in-tube solid phase microextraction (IT-SPME) with direct analysis in real time mass spectrometry (DART-MS) was realized for the first time and applied in the analysis of triazine herbicides in lake water and orange juice. We incorporated single-wall carbon nanotubes (SWNTs) into a polymer monolith containing methacrylic acid (MAA) and ethylene dimethacrylate (EDMA) to form a novel poly(methacrylic acid-co-ethylene dimethacrylate-co-single wall carbon nanotubes) (poly(MAA-EDMA-SWNT)) monolith, which was then used in IT-SPME for enrichment of six triazine herbicides from water samples. With the online combination of IT-SPME with DART-MS, the analytes desorbed from the monolith were directly ionized by DART and transferred into MS for detection, thus rapid determination was achieved. Compared with regular DART-MS method, this online IT-SPME-DART-MS method was more sensitive and reproducible, because of the IT-SPME procedures and the isotope-labeled internal standard used in the experiment. Six triazine herbicides were determined simultaneously using this method with good linearity (R(2) > 0.998). The limit of quantification (signal-to-noise ratio of S/N = 10) of the six herbicides were only 0.06-0.46 ng/mL. The proposed method has been applied to determine triazine herbicides in lake water and orange juice, showing satisfactory recovery (85%-106%) and reproducibility (relative standard deviation of RSD = 3.1%-10.9%).

Investigations on the Degradation of Triazine Herbicides in Water by Photo-Fenton Process

In this work, the degradation of 2-chloro-4,6-diamino-1,3,5-triazine in aqueous solutions by photo-Fenton process has been investigated. The preliminary results have shown that the degradation of 2-chloro-4,6-diamino-1,3,5-triazine by photo-Fenton process is more rapid and more effective than Fenton and UV/H2O2 processes. The effects of certain experimental parameters on kinetics and efficiency of the degradation of 2-chloro-4,6,-diamino-1,3,5-triazine by photo-Fenton process, have been evaluated. Under optimal conditions, photo-Fenton process achieved more than 90% of chloride release and about 30% of nitrate formation. The results of total organic carbon (TOC) and total Kjeldahl nitrogen (TKN) analyses have shown that no carbon dioxide and ammonia are formed during photo-Fenton treatment of aqueous solutions containing 40 mg/L triazine. These results indicate that only substituent groups of triazine ring are released; however, nitrogen atoms of triazine ring remain unaffected. A simple mechanism of degradation of 2-chloro-4,6-diamino-1,3,5-triazine has been proposed. The degradation starts by a rapid release of chlorine atoms as chloride ions to form 2-hydroxy-4,6-diamino-1,3,5-triazine. The amino groups of 2-hydroxy-4,6-diamino-1,3,5-triazine undergo are oxidized into nitro groups by hydroxyl radicals to form 2-hydroxy-4,6-dinitro-1,3,5-triazine which undergoes a slow release of nitro groups and their substitution with hydroxyl groups to form cyanuric acid and nitrate ions. The degradation of cyanuric acid by photo-Fenton process has also been investigated. The results of TOC and TKN analyzes show that no carbon dioxide is formed during the treatment.

Dispersive liquid–liquid microextraction method based on solidification of floating organic droplet for the determination of triazine herbicides in water and sugarcane samples

Dispersive liquid–liquid microextraction method based on solidification of floating organic droplet (DLLME-SFO) was developed for the analysis of triazines. As model compounds four selected triazine herbicides namely, simazine, atrazine, secbumeton and cyanazine were employed to estimate the extraction efficiency. The experimental conditions were comprehensively studied for the DLLME-SFO method. Under the use of 10μL of 1-undecanol as extraction solvent, 100μL of acetonitrile as disperser solvent and 5% (w/v) NaCl for 3min the results demonstrated that the repeatability (RSD%) of the optimised DLLME-SFO method ranged from 0.03% to 5.1% and the linearity in the range of 0.01–100ppb. Low limits of detection (0.037–0.008ppb), and good enrichment factors (195–322) were obtained. The DLLME-SFO method applied in water and sugarcane samples showed excellent relative recoveries (95.7–116.9%) with RSDs <8.6% (n=3) for all samples.

Determination of Triazine Herbicides in Environmental Samples by Dispersive Liquid-Liquid Microextraction Coupled with High Performance Liquid Chromatography

A simple, rapid, efficient, and environmentally friendly method for the determination of five triazine herbicides in water and soil samples was developed by using dispersive liquid-liquid microextraction (DLLME), coupled with high performance liquid chromatography-diode array detection (HPLC-DAD). The water samples were directly used for DLLME extraction. For soil samples, the target analytes were first extracted by water-methanol (99:1, v/v). In the DLLME extraction method, chloroform was used as an extraction solvent, and acetonitrile as a dispersive solvent. Under the optimum conditions, the enrichment factors of DLLME were in the range between 183-221. The linearity of the method was obtained in the range of 0.5-200 ng/mL for the water sample analysis, and 1-200 ng/g for the soil samples, respectively. The correlation coefficients ranged from 0.9968 to 0.9999. The limits of detection were 0.05-0.1 ng/mL for the water samples, and 0.1-0.2 ng/g for the soil samples. The proposed method has been successfully applied to the analysis of target triazine herbicides (simazin, atrazine, prometon, ametryn, and prometryn) in water and soil samples with satisfactory results.

Combined Use of Liquid–Liquid Microextraction and Carbon Nanotube Reinforced Hollow Fiber Microporous Membrane Solid-Phase Microextraction for the Determination of Triazine Herbicides in Water and Milk Samples by High-Performance Liquid Chromatography

A simple, efficient and environmentally friendly method for the extraction and determination of five triazine herbicides in water and milk samples was developed by simultaneous liquid–liquid microextraction and carbon nanotube reinforced hollow fiber microporous membrane solid-phase microextraction coupled with high-performance liquid chromatography–diode array detection. The parameters that affect the extraction efficiencies, including the type and concentration of multi-walled carbon nanotube, type of membrane solvent and desorption solvent, the type and volume of the extraction solvent in sample solution, extraction time and temperature, the pH of sample solution, stirring rate, and ionic strength were investigated and optimized. Under the optimum conditions, the method shows a good linearity within a range of 0.5–200 ng mL−1 for water samples and 1–200 ng mL−1 for milk samples, with the correlation coefficients (r) varying from 0.9991 to 0.9998 and from 0.9989 to 0.9994, respectively. The limits of detection were in the range between 0.08 and 0.15 ng mL−1 for water samples and 0.3 and 0.5 ng mL−1 for milk samples, while the relative standard deviations varied from 4.6% to 6.9% and from 5.3% to 7.7%, respectively. The recoveries of the target analytes at spiking levels of 5.0 and 50.0 ng mL−1 were in the range from 86.6% to 106.8% for water samples and from 81.3% to 97.4% for milk samples. The results demonstrated that the developed method was an efficient pretreatment and enrichment procedure for the determination of triazine pesticides in real water and milk samples.

A fast screening method for the presence of atrazine and other triazines in water using flow injection with chemiluminescent detection

Atrazine is a triazine herbicide which contains two secondary aliphatic amine groups. Previous studies have shown that aliphatic amines react with tris(2,2′-bipyridyl)ruthenium(III) to produce chemiluminescence. This paper describes the application of tris(2,2′-bipyridyl)ruthenium(III) to the detection of atrazine and related triazine herbicides in water by flow injection chemiluminescence analysis. The optimised experimental conditions were determined to be: sample and carrier flow rates of 4.6 mL min −1, sample at pH 9 buffered with 50 mM borax, and reagent concentration of 1 mM tris(2,2′-bipyridyl)ruthenium(III) in 20 mM H 2SO 4 (pH 1). Under these conditions, the logarithm of the chemiluminescence intensity versus concentration was linear in the range of 2.15–2150 μg L −1 for samples in MilliQ water, and the limit of detection of atrazine in water was determined to be 1.3 ± 0.1 μg L −1. Validation of the method was performed using direct injection HPLC. The presence of natural organic matter (NOM) significantly increased the chemiluminescence, masking the signal generated by atrazine. Isolating the target analyte via solid phase extraction (SPE) prior to analysis removed this interference and concentrated the samples, resulting in a greatly improved sensitivity with a detection limit of 14 ± 2 ng L −1.

Preparation of new solid phase micro extraction fiber on the basis of atrazine-molecular imprinted polymer: Application for GC and GC/MS screening of triazine herbicides in water, rice and onion

A simple polymerization strategy has been used to produce a monolithic solid phase micro extraction (SPME) fiber on the basis of molecularly imprinted polymer able to couple with GC and GC–MS for selective extraction and analysis of triazine herbicides. A fiber was produced by copolymerization of methacrylic acid–ethylene glycol dimethacrylate imprinted with atrazine. The effective factors influencing the polymerization have been investigated and are detailed here. At the optimum conditions the prepared fiber is firm, inexpensive, durable and thermally stable up to 280 °C which has vital importance in SPME coupled with GC or GC/MS. In addition, the influences of pH, extraction time and temperature on the extraction efficiency of analytes were optimized. Selectivity of prepared fibers in relation to triazine herbicides and some of the other pesticide has been investigated. The high extraction efficiency was obtained for atrazine, simazine, propazine, cyanazine, ametryn, terbutryn and prometryn yielding the detection limits of 20, 70, 80, 81, 69, 88 and 68 ng mL −1, respectively and the high quantities of recoveries. The reliability of prepared fiber to extraction of atrazine and other analogues in real samples has been investigated and proved by implementation of SPME in spiked samples such as tap water, onion and rice.

Use of quadrupole time-of-flight mass spectrometry in environmental analysis: elucidation of transformation products of triazine herbicides in water after UV exposure.

The high resolution and exact mass capabilities of hybrid quadrupole time-of-flight (QTOF) mass spectrometry can provide an ultimate confirmation in target analysis mode and aid in discovery and elucidation of unknown analytes. In this paper, the latter approach has been applied to study the transformation products of selected pesticides (terbuthylazine, simazine, terbutryn, terbumeton) in environmental waters. Additionally, the usefulness of software modules, originally designed for drug metabolism discovery, has been tested. Different environmental waters spiked at a 0.5 microg/mL level have been irradiated with a mercury lamp for 7 days, sampling 3-mL aliquots every approximately 12 h. After centrifugation, 50 microL was directly injected in an LC-ESI-QTOF system. The high sensitivity in full-scan mode allowed us to elucidate minor metabolites even below 2% of the total peak area. The mass errors observed in almost every case fell below 2 mDa, allowing assignment of a highly probable empirical formula. Besides, the MS/MS capability of this tandem instrument was very useful for differentiation between isomeric transformation products. This work shows that hyphenated LC-QTOF is a powerful approach for the rapid screening and confirmation of unknown pesticide transformation products in environmental water.

Gas chromatography/ion trap mass spectrometry applied for the analysis of triazine herbicides in environmental waters by an isotope dilution technique

A gas chromatography/ion trap mass spectrometry method was developed for the analysis of simazine, atrazine, cyanazine, as well as the degradation products of atrazine, such as deethylatrazine and deisopropylatrazine in environmental water samples. Isotope dilution technique was applied for the quantitative analysis of atrazine in water at low ng/l levels. One liter of water sample spiked with stable isotope internal standard atrazine-d 5 was extracted with a C 18 solid-phase extraction cartridge. The analysis was performed on an ion trap mass spectrometer operated in MS/MS method. The extraction recoveries were in the range of 83–94% for the triazine herbicides in water at the concentrations of 24, 200, and 1000 ng/l, while poor recoveries were obtained for the degradation products of atrazine. The relative standard deviation (R.S.D.) were within the range of 3.2–16.1%. The detection limits of the method were between 0.75 and 12 ng/l when 1 l of water was analyzed. The method was successfully applied to analyze environmental water samples collected from a reservoir and a river in Hong Kong for atrazine detected at concentrations between 3.4 and 26 ng/l.

Determination of triazine herbicides in water by micellar electrokinetic capillary chromatography

Capillary electrophoresis was applied to the analysis of a mixture of triazine herbicides of environmental interest. Micellar electrokinetic capillary chromatography (MECC) proved to be satisfactory for the separation of triazines, providing high efficiency in short analysis times. Several electrophoretic parameters were investigated: injection conditions, pH and buffer concentration, surfactant concentration and applied voltage. The optimized MECC method was applied to the determination of these compounds in water samples; using a solid-phase concentration step, herbicide concentrations lower than 0.2 ng/ml can be measured, the relative standard deviations being about 20%.

Enzyme-immunoassay techniques for the detection of atrazine in water samples: Evaluation of a commercial tube based assay

Environmental immunoassays can help lower the operating costs and improve the effectiveness of residue laboratories. The present study assesses the ability of a commercially available enzyme immunoassay (EIA) to detect triazine herbicides in water. The tube based EIA could detect atrazine in lake and river water with detection limits of 62 pg/mL and 180 pg/mL respectively. The assay's ability to quantify atrazine in a set of 124 water samples taken from many parts of Canada was compared with a reference method that used gas chromatographic separation combined with a nitrogen phosphorous detector (GC-NPD) (R=0.919). A 71 % reduction in analytical load was achieved at a threshold concentration of 1 ng/mL. There were 2.4 % false negative and 0.8 % false positive results associated with that load reduction. The variability of the assay control parameters was generally within two standard deviations of the mean response for 65 assays. The EIA for atrazine is recommended for use as a screening technique and as an inexpensive way to monitor triazine levels in waters that are known to be contaminated with those herbicides.

Behaviour of polycyclic aromatic hydrocarbons (PAHs) and triazine herbicides in water and aquifer material of a drinking water recharge plant

On the background of a discipline overlapping research project of the «Deutsche Forschungsgemeinschaft» (DFG), entitled: Pollutants in ground water, the behaviour of PAHs and triazine herbicides during the water gathering process by means of underground passage was investigated. The publication is divided into four parts (I-IV). In the present part the area of investigation including the monitoring network and the determination methods for PAHs and triazine herbicides in the aqueous matrix are described