Determination Of Herbicides In Water Research Articles

Development and greenness evaluation of solid-phase extraction and salting-out liquid–liquid extraction method for determination of herbicides in water, soil and rice

Development and greenness evaluation of solid-phase extraction and salting-out liquid–liquid extraction method for determination of herbicides in water, soil and rice

Synchronous extraction and determination of phenoxy acid herbicides in water by on-line monolithic solid phase microextraction-high performance liquid chromatography

A C18 monolithic capillary column was utilized as the solid phase microextraction column to construct an in-tube SPME-HPLC system which was used to simultaneously extract and detect five phenoxy acid herbicides, including 2,4-dichlorophenoxyacetic acid (2,4-D), 2- (2-chloro)-phenoxy propionic acid (2,2-CPPA), 2-(3-chloro)-phenoxy propionic acid (2,3- CPPA), phenoxy propionic acid (PPA) and 2-(2,4-dichlorophenoxy) propionic acid (2,4-DP). The operating parameters of the in-tube SPME-HPLC system, including the length of the monolithic column, the sampling flow rate, the sampling time, the elution flow rate and the elution time, had been investigated in detail. The optimized operating parameters of the in-tube SPME-HPLC system were as follow: the length of the monolithic column was 20 cm, the sampling flow rate was 0. 04 mL/min, sampling time was 13 min; the elution flow rate was 0.02 mL/min, elution time was 5 min. Under the optimized conditions, the detection limits of the five phenoxy acid herbicides were as follows: 9 µg/L for PPA, 4 µg/L for 2,2-CPPA, 4 µg/L for 2,3-CPPA, 5 µg/L for 2,4-D, 5 µg/L for 2,4-DP. Compared with the HPLC method with direct injection, the combined system showed a good enrichment factors to the analytes. The recoveries of the five phenoxy acid herbicides were between 79.0% and 98.0% (RSD ≤ 3.9%). This method was successfully used to detect the five phenoxy acid herbicides in water samples with satisfactory results.

Determination of Phenoxy-acid Herbicides in Water with Solid Phase Microextraction Fiber Coated with Single-walled Carbon Nanotubes

By using solid phase microextraction( SPME) fiber coated with single-walled carbon nanotubes,an analytical method based on derivatization-SPME-GC-ECD method was established for the determination of 5 phenoxy-acid herbicides in water. The extraction parameters of the method were optimized,and the chemical stability of the SWCNTs fiber was investigated. The results showed that due to the inert nature of graphite,the SWCNTs fiber could be used at pH as low as 1 and the extraction efficiency of the fiber would not decline significantly after 160 extractions,showing excellent chemical stability. The linear range of the established method was 0. 5-50. 0 μg / L for Dicamba,( ±)-2-( 2,4,5-trichlorophenoxy) propionic acid( 2,4,5-TP)and trichlorophenoxy acetic acie( 2,4,5-T),1. 0-100. 0 μg / L for 2,4-dichloraphenoxy acetic acid( 2,4-D),and 5. 0-500. 0 μg / L for 4-( 2,4-dichlorophenoxy) bytyric acid( 2,4-DB). The LODs and LOQs were0. 03-0. 25 μg / L and 0. 08-0. 84 μg / L,respectively.

Fast determination of herbicides in waters by ultra‐performance liquid chromatography/tandem mass spectrometry

A rapid multiresidue method for the analysis of more than 40 herbicides (such as simazine, terbuthylazine and diuron) in waters has been developed and validated by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC/MS/MS). Prior to chromatographic determination, the samples were extracted using a solid-phase extraction procedure. The analysis was performed on an Acquity UPLC BEH C(18) column using a gradient elution profile and a mobile phase consisting of methanol and an aqueous solution of formic acid (0.01%). Other chromatographic and MS/MS parameters were optimised in order to improve selectivity and sensitivity of the analytes. The analytes were detected using electrospray ionisation (ESI)-MS/MS in positive ion mode with multiple reaction monitoring (MRM), optimising parameters such as voltage cone, capillary voltage, source and desolvation temperature, and desolvation and cone gas flow. The optimised method provides a rapid separation (less than 10 min) of the selected herbicides in the assayed matrices, and it was validated by the analysis of spiked blank matrix samples. Good linearity was obtained and the repeatability of the method was less than 20% for the lowest calibration point. The limits of detection ranged from 0.002 to 0.02 microg/L, and the limits of quantification from 0.005 to 0.05 microg/L, which were below the values specified by the European Union. Finally, the method was successfully applied to real environmental samples from Andalusia (southern Spain). Terbuthylazine, simazine, atrazine desisopropyl and desethyl terbuthylazine were the herbicides most frequently found in water samples.

An interlaboratory study to evaluate potential matrix reference materials for herbicides in water

Matrix reference materials (MRM) are essential tools for the validation of analytical protocols. Nowadays, there are no such materials for the determination of herbicides in water. Pesticides stored in acetonitrile and stored on solid phase extraction (SPE) cartridges previously percolated with a water sample spiked with triazines and phenylureas have proven to be good candidates for reference materials because of their satisfactory stability under appropriate temperature conditions. To evaluate the behaviors of these materials containing pesticides and to be analyzed by liquid chromatography, a collaborative study including 15 laboratories has been organized. Observed reproducibility on candidate materials after the removal of extreme results was 16.1% for the vials with pesticides in acetonitrile (at around 0.125 mg/L) directly analyzed, 29.2% for a water sample spiked with the pesticides (at around 0.5 μg/L) analyzed after preconcentration on a cartridge and 26.7% for the cartridges previously percolated with a water containing the pesticides (250 mL at around 0.5 μg/L for each pesticide) analyzed after elution. Such dispersion values are quite compatible with the requirement of a further certification for such materials.

Feasibility study of a reference material for water chemistry: Long term stability of triazine and phenylurea residues stored in vials or on polymeric sorbents

Matrix Reference Materials (MRM) are essential tools for the validation of analytical protocols. Nowadays, there are no such materials for the determination of herbicides in water. So, a feasibility study of a MRM for the analysis of triazines and phenylureas in water was carried out. Different kinds of candidates MRM were prepared: solutions of pesticides diluted in acetonitrile and stored in sealed vials or stored at the dry state after the evaporation of the solvent to dryness, pesticides stored on two different types of polymeric solid-phase extraction (SPE) sorbents after the percolation of drinking or river waters spiked with pesticides. The stability of these candidates MRM stored at various temperatures (room temperature, 0.5 °C or −18 °C) was studied over a period of approximately 1 year. Two different levels of concentration were studied for each kind of material. During the storage, some samples of each different MRM candidate were monthly analyzed by liquid chromatography. Results showed that, among the candidate materials, some of them presented satisfactory enough stability to consider a further certification. They were either pesticides in solution in sealed vials or pesticides stored on cartridges after the percolation of spiked water samples. However, it was shown that these different MRM candidates had to be stored at a temperature lower than 0.5 °C.

Multiresidue HPLC methods for phenyl urea herbicides in water.

High-performance liquid chromatography (HPLC) methods for the determination of phenyl urea herbicides in water are described. The target compounds include chlortoluron, diuron, fluometuron, isoproturon, linuron, metobromuron, metoxuron, monuron, neburon, and siduron. Water was subjected to solid phase extraction (SPE) using either automated SPE with 47 mm C(18) Empore disks or on-line precolumn concentration. Herbicides were separated on a C(18) reversed phase column with an acetonitile-water gradient and were detected with either a diode array detector (DAD) or a postcolumn photolysis and derivatization (PPD) detector system. Photolysis converted the phenyl ureas to monoalkylamines that were derivatized to fluorescent isoindoles by reaction with o-phthalaldehyde and 2-mercaptoethanol. The DAD monitoring at 245 nm was linear over three decades with instrument detection limits of approximately 0.01 mg/L. SPE efficiency was between 48 and 70% in laboratory reagent water, but use of the internal standard quantitation method improved accuracy. High total dissolved solids and total organic carbon values in surface water improved recoveries relative to laboratory reagent water for all of the phenyl ureas. In Colorado River water spiked at 1 or 50 microg/L, mean recoveries ranged from 74 to 104%. Method detection limits (MDLs) ranged from 4 to 40 ng/L (parts per trillion) with the DAD instrument. PPD detection was highly specific but resulted in a slight loss in chromatographic efficiency and average MDLs approximately 5 times higher using a single set of detection conditions. The study indicates that methods based on SPE followed by HPLC with diode array or PPD detection have practical utility for trace analysis of phenyl ureas in drinking water or surface waters.

Surface Functionalization of Porous Polypropylene Membranes with Molecularly Imprinted Polymers by Photograft Copolymerization in Water

In the presence of a template, desmetryn, commercial porous polypropylene membranes were photografted, using benzophenone as photoinitiator, with the functional monomer 2-acrylamido-2-methylpropanesulfonic acid and the cross-linker N,N‘-methylenebis(acrylamide) in water. The influence of the polymerization conditions on membrane properties was studied by solute sorption analyses and membrane permeability measurements as well as electron spectroscopy for chemical analysis, FTIR spectroscopy, BET analysis, and scanning electron microscopy. It was found that molecularly imprinted polymer (MIP) membranes can be obtained which possess group affinity for the template and other triazine herbicides. Remarkably, the MIP membrane affinity for the template in buffer solution can be improved by the presence of salt during photograft copolymerization. This work presents the first successful example for molecular imprinting by in situ polymerization in water and on the surface of a commercially available synthetic polymer. The novel MIP membranes can be used in a fast preconcentration step, solid-phase extraction, by a simple microfiltration for the determination of herbicides in water. The possibility to introduce specific binding sites into porous membranes by surface imprinting polymerization without reducing their high permeabilities opens a general way to design new high-performance affinity membranes.

On-line preconcentration, cleanup and high-performance liquid chromatographic determination of chlorophenoxy acid herbicides in water

Abstract A rapid and simple technique for the determination of six chlorophenoxy acid herbicides in water is described. After extraction and preconcentration of the analytes at pH≈ 1 in a small 20 × 2 mm I.D. polymeric reversed-phase precolumn, an on-line cleanup procedure is performed by a selective transfer of the ionized compounds to a second precolumn packed with an anion exchanger. An acetonitrile-sodium hydroxide (pH 10; 10:90, v/v) solution is used for this step. The anionexchange precolumn is further on-line analyzed by reversed-phase chromatography with gradient elution and UV detection at 230 nm. The recovery of the examined herbicides is nearly 100% with a R.S.D.

Simultaneous Determination of Herbicides in Water by Using FRIT/FAB-LC/MS.

Simultaneous Determination of Herbicides in Water by Using FRIT/FAB-LC/MS.

The Use of Silar 10 CP for the Packed Column Gas Chromatographic Determination of Chlorophenoxyacetic Acid Herbicides in Water and Sediments

Abstract The determination of chlorophenoxyacetic acid herbicide residues was done with GC-ECD as pentafluorobenzyl derivatives. The herbicides were separated on a 3% Silar 10 CP column, which permits better resolution from interfering organic acids of environmental origin. The fortification study provides an 84–91% recovery for the water and sediment samples. The detection limits were established as 0.1 μg/1 for the water and 1.0–1.5 ng/g for the sediment samples. The use of a 3%Silar 10 CP packed column in the monitoring study as compared with a 1.5% OV-17 + 1.95% QF-1 one, shows the very small amount of contamination of the samples with these herbicide classes.

Bioassay for the determination of herbicides in water: Methods and sensitivity

Bioassay for the determination of herbicides in water: Methods and sensitivity

Sample enrichment and GC-MS determination of herbicides in water

A sample enrichment method for herbicides from water, based on chromatographic extraction of organic compounds using graphitized carbon black is presented and its advantages and limits described. GC-MS and ECD are employed for qualitative analysis and quantitative determination.