Assessment of Envi-Carb™ as a passive sampler binding phase for acid herbicides without pH adjustment.
The graphitised carbon solid phase extraction (SPE) sorbent Envi-Carb has been used to fabricate glass fibre filter- Envi-Carb "sandwich" disks for use as a passive sampler for acid herbicides. Passive sampler uptake of a suite of herbicides, including the phenoxyacetic acid herbicides 4-chloro-o-tolyloxyacetic acid (MCPA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 3,6-dichloro-2-methoxybenzoic acid (Dicamba), was achieved without pH adjustment, demonstrating for the first time a suitable binding phase for passive sampling of acid herbicides at neutral pH. Passive sampling experiments with Duck River (Tasmania, Australia) water spiked at 0.5 μg L(-1) herbicide concentration over a 7 d deployment period showed that sampling rates in Duck River water decreased for seven out of eight herbicides, and in the cases of 3,6-dichloro-2-pyridinecarboxylic acid (Clopyralid) and Dicamba no accumulation of the herbicides occurred in the Envi-Carb over the deployment period. Sampling rates for 4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid (Picloram), 2,4-D and MCPA decreased to approximately 30% of the sampling rates in ultrapure water, whilst sampling rates for 2-(4,6-dimethylpyrimidin-2-ylcarbamoylsulfamoyl) benzoic acid, methyl ester (Sulfometuron-methyl) and 3,5,6-Trichloro-2-pyridinyloxyacetic acid (Triclopyr) were approximately 60% of the ultrapure water sampling rate. For methyl N-(2,6-dimethylphenyl)-N-(methoxyacetyl)-D-alaninate (Metalaxyl-M) there was little variation in sampling rate between passive sampling experiments in ultrapure water and Duck River water. SPE experiments undertaken with Envi-Carb disks using ultrapure water and filtered and unfiltered Duck River water showed that not only is adsorption onto particulate matter in Duck River water responsible for a reduction in herbicide sampling rate, but interactions of herbicides with dissolved or colloidal matter (matter able to pass through a 0.2 μm membrane filter) also reduces the herbicide sampling rate.
School of Chemistry, University of Tasmania, Locked Bag 1371, Launceston, Tasmania 7250, Australia. Electronic address: Andrew.Seen@utas.edu.au.
Andrew
A
Seen
School of Chemistry, University of Tasmania, Locked Bag 1371, Launceston, Tasmania 7250, Australia.
Oceane
O
Bizeau
School of Chemistry, University of Tasmania, Locked Bag 1371, Launceston, Tasmania 7250, Australia.
Lachlan
L
Sadler
Analytical Services Tasmania, Department of Primary Industries, Parks, Water and Environment, 18 St John's Ave, Hobart, Tasmania 7008, Australia.
Timothy
T
Jordan
Analytical Services Tasmania, Department of Primary Industries, Parks, Water and Environment, 18 St John's Ave, Hobart, Tasmania 7008, Australia; Central Science Laboratory, University of Tasmania, Private Bag 74, Hobart, Tasmania 7001, Australia.
David
D
Nichols
D015084:2,4-Dichlorophenoxyacetic Acid / Q000032:analysis; D000143:Acids / Q000737:chemistry*; D005374:Filtration / Q000295:instrumentation*; D006540:Herbicides / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D010848:Picolinic Acids / Q000032:analysis; D052616:Solid Phase Extraction / Q000295:instrumentation*; D013453:Sulfonylurea Compounds / Q000032:analysis; D013648:Tasmania; D014874:Water Pollutants, Chemical / Q000032:analysis*
D000143:Acids; D006540:Herbicides; D010848:Picolinic Acids; D013453:Sulfonylurea Compounds; D014874:Water Pollutants, Chemical; D015084:2,4-Dichlorophenoxyacetic Acid; C042031:sulfometuron methyl; C030614:picolinic acid
Envi-Carb; Herbicides; Passive sampling; Phenoxyacetic acid herbicides