Laboratory Products
Automated One Step SPE and Concentration of Nitrogen and Phosphorus Containing Pesticides in Water
Sep 07 2011
Introduction
Replacing organochlorine pesticides, nitrogen and phosphorus containing pesticides are widely used both domestically and globally. Initially considered more desirable than organochlorine pesticides because of their rapid breakdown in the environment, they operate by inhibiting the enzyme acetylcholinesterase disrupting nerve function. They have been shown, particularly organophosphates, to be extremely toxic to vertebrates. Despite their rapid breakdown, these compounds have been shown to persist in drinking water, and due to their extreme toxicity, represent a major health concern. The following procedure outlines the use of Solid Phase Extraction (SPE) to extract phosphorus and nitrogen containing pesticides for analysis by GC via EPA methods 507, 614, 1657 and 8141.
Instrumentation & Consumables
• FMS, Inc. Power Prep SPE System
• FMS, Inc. PowerVap Concentrator
• FMS, Direct to Vial concentrator tubes
• Water’s 1gm Oasis HLB® Cartridge
• Varian Chem Elut Hydromatrix® cartridge
• Thermo Trace GC w/Polaris QMS
PowerPrep SPE
The HLB Cartridge is conditioned with 10ml Methanol
The HLB Cartridge is conditioned with 10ml DI H2O
Sample is loaded across HLB Cartridge via vacuum
The sample bottle is auto rinsed and rinse loaded on HLB
The cartridge is dried with Nitrogen
The cartridge is eluted with ethyl acetate followed by methylene chloride, passed across a Chem Elut Hydromatrix® cartridge and eluted directly into the Direct to Vial FMS PowerVap .
PowerVap Concentrator
Pre-heat temp: 55 deg C
Pre-heat time: 30 minutes
Heat in Sensor mode: 55 deg C
Nitrogen Pressure: 15 PSI
Procedure
Sample Prep & Extraction
Two 1 liter water samples spiked using Ultra NPM-525C & NPM-525BNitrogen/Phosphorus Pesticide Mix (Diluted).
The samples are acidified to PH <2. Samples are equilibrated for 15 minutes. Two samples are loaded onto to corresponding sample positions on FMS PowerPrep SPE System.
The Program is initiated to run each sample sequentially. The sample is extracted and automatically transferred to FMS PowerVap Concentrator with Direct to Vial tubes. The extracts are concentrated with the PowerVap to <1 ml.
The Extracts are removed from the PowerVap, volume adjusted to 1ml, internal standard added (Ultra ISM-510) and transferred to Agilent GC for analysis.
Figure #1. FMS Power Prep SPE with PowerVap Concentrator
Results
Compound | Position #1 | Position #2 | Mean Rec | RSD |
Alachlor | 4.72 | 4.61 | 93.30% | 2.40% |
Ametryn | 4.46 | 4.5 | 89.60% | -0.90% |
Atraton | 4.59 | 4.26 | 88.50% | 7.50% |
Atrazine | 4.49 | 4.42 | 89.10% | 1.60% |
Bromacil | 4.18 | 5.07 | 92.50% | -19.20% |
Butachlor | 4.08 | 4.09 | 81.70% | -0.20% |
Butylate | 3.62 | 3.54 | 71.60% | 2.20% |
Carboxin | 4.3 | 3.64 | 79.40% | 16.60% |
Chlorophram | 4.61 | 4.17 | 87.80% | 10.00% |
Cycloate | 4.11 | 3.9 | 80.10% | 5.20% |
Dichlorvos | 4.23 | 3.91 | 81.40% | 7.90% |
Diphenamid | 4.13 | 4.55 | 86.80% | -9.70% |
Disulfoton* | 4.03 | 3.32 | 73.50% | 19.30% |
EPTC | 3.74 | 3.41 | 71.50% | 9.20% |
Ethoprop | 4.64 | 4.44 | 90.80% | 4.40% |
Fenamiphos | 4.21 | 5.07 | 92.80% | -18.50% |
Fenarimol | 5.27 | 4.82 | 100.90% | 8.90% |
Fluridone | 5.51 | 5.06 | 105.70% | 8.50% |
Hexazinone | 4.86 | 4.69 | 95.50% | 3.60% |
Methyl Paraoxon | 5.35 | 5.56 | 109.10% | -3.80% |
Metolachlor | 4.5 | 4.41 | 89.10% | 2.00% |
Mevinphos | 4.57 | 4.38 | 89.50% | 4.20% |
MGK 264 | 4.13 | 3.59 | 77.20% | 14.00% |
Molinate | 4.24 | 3.97 | 82.10% | 6.60% |
Napropamide | 4.49 | 4.28 | 87.70% | 4.80% |
Norflurazon | 4.74 | 4.67 | 94.10% | 1.50% |
Pebulate | 4.07 | 3.52 | 75.90% | 14.50% |
Prometon | 4.16 | 4.3 | 84.60% | -3.30% |
Prometryn | 4.4 | 4.57 | 89.70% | -3.80% |
Pronamide⁺* | 4.46 | 4.36 | 88.20% | 2.30% |
Propazine | 4.72 | 4.55 | 92.70% | 3.70% |
Simazine | 4.2 | 4.24 | 84.40% | -0.90% |
Simetryn | 4.79 | 4.73 | 95.20% | 1.30% |
Stirofos | 4.33 | 4.4 | 87.30% | -1.60% |
Tebuthiuron | 4.36 | 4.18 | 85.40% | 4.20% |
Terbacil | 4.81 | 5.33 | 101.40% | -10.30% |
Terbufos⁺* | 3.58 | 3.51 | 70.90% | 2.00% |
Terbutryn | 4.43 | 4.82 | 92.50% | -8.40% |
Triademefon | 5.69 | 4.82 | 105.10% | 16.60% |
Tricyclazole | 5.25 | 4.95 | 102.00% | 5.90% |
Vernolate | 3.69 | 3.529 | 72.20% | 4.50% |
Conclusions
Analysis of duplicate samples across the Automated One Step PowerPrep SPE Direct to Vial Concentration system demonstrates highly efficient extractions with excellent recoveries and reproducibility. Watch the product video
For more information contact FMS at:
FMS. Inc.
580 Pleasant Street
Watertown, MA 02472
Phone: (617) 393-2396
Fax: (617) 393-0194
Email: onlineinfo@fms-inc.com
Web site: www.fmsenvironmental.com
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