Method 505: Analysis of Organohalide Pesticides and Commercial PCBs in Water by Microextraction and GC
by Microextraction and Gas Chromatography
With the advent of modern agriculture and its vast selection of chemical pest control measures, the farming community has made significant increases in productivity and efficiency. Crop yield per acre is extremely high, due in part to the role of pesticides and herbicides in mitigating the devastating effects of many plant and insect pests. However, the use of these chemicals can have drawbacks, including surface and ground water contamination. EPA Method 505 is used for organohalide pesticide analysis in drinking and ground water. The Rtx-CLPesticides and Rtx-CLPesticides2 column set works well for the analysis of organohalide compounds because the columns are highly selective for analytes that contain electronegative substituents. The optimized parallel dual-column method shown here provides fast analysis times, which improves sample throughput.
| Vendor | Column Pair | Analysis Time (min) | Coelutions | Restek Advantage |
|---|---|---|---|---|
| Restek | Rtx-CLPesticides / Rtx-CLPesticides2 |
18 / 18.5 | 1 / 1 |
|
| Competitor A | column 1 / column 2 | 14 / 14 | 0 / 1 | |
| Competitor B | column 1 / column 2 | 35 / 36 | 1 / 2 |
Comparison based on published competitor data. All columns tested were 0.32 mm ID.
Organohalide pesticide analysis (Method 505) on Rtx-CLPesticides and Rtx-CLPesticides2 columns.
| Peaks | |
|---|---|
| 1. | Hexachlorocyclopentadiene |
| 2. | Hexachlorobenzene |
| 3. | Simazine |
| 4. | Atrazine |
| 5. | γ-BHC |
| 6. | Heptachlor |
| 7. | Alachlor |
| 8. | Aldrin |
| Peaks | |
|---|---|
| 9. | Heptachlor epoxide |
| 10. | trans-Chlordane |
| 11. | trans-Nonachlor |
| 12. | cis-Chlordane |
| 13. | Dieldrin |
| 14. | Endrin |
| 15. | cis-Nonachlor |
| 16. | Methoxychlor |
| Columns | Rtx-CLPesticides 30 m, 0.32 mm ID, 0.32 µm (cat.# 11141) |
|---|---|
| and Rtx-CLPesticides2 30 m, 0.32 mm ID, 0.25 µm (cat.# 11324) | |
| using Rxi guard column 5 m, 0.32 mm ID (cat.# 10039) | |
| with deactivated universal “Y” Press-Tight connector (cat.# 20405-261) | |
| Standard/Sample | 200 ng/mL 505 organohalide pesticide mix (cat.# 32024) |
| 4.2 µg/mL simazine (cat.# 32236) | |
| 4.2 µg/mL atrazine (cat.# 32208) | |
| Diluent: | Methanol |
| Injection | |
| Inj. Vol.: | 2 µL splitless (hold 0.75 min) |
| Liner: | Cyclo double taper (4 mm) (cat.# 20896) |
| Inj. Temp.: | 250 °C |
| Oven | |
| Oven Temp.: | 90 °C (hold 1 min) to 310 °C at 10 °C/min (hold 5 min) |
| Carrier Gas | He, constant flow |
| Linear Velocity: | 40 cm/sec |
| Detector | Micro-ECD @ 325 °C |
|---|---|
| Instrument | Agilent/HP6890 GC |
| Notes | This chromatogram was obtained using an Agilent micro-ECD. To obtain comparable results, you will need to employ a micro-ECD in addition to confirmational dual columns connected to a 5-meter guard column using a “Y” Press-Tight connector. |