Laserfiche WebLink
Pesticides/PCBs Method TO-10A <br /> 12.1.13 For improved resolution use a capillary column such as an 0.25-mm I.D.x 30-m DB-5 with 0.25 gm <br /> film thickness. The following conditions are appropriate. <br /> • Helium carrier gas at 1 mL/min. <br /> • Column temperature program,90'C(4 min)/16'C/min to 154'C/4'C/min to 270'C. <br /> • Detector,13 Ni ECD at 350°C. <br /> • Make up gas,nitrogen,or 5%methane/95%argon at 60 mL/min. <br /> • Splitless injection,2 pL maximum. <br /> • Injector temperature,220°C. <br /> 12.1.14 Class separation and improved specificity can be achieved by column chromatographic separation <br /> on Florisil(6). <br /> 12.2 Analysis of Organophosphorus Pesticides by Capillary Gas Chromatography with Flame <br /> Photometric or Nitrogen-Phosphorus Detectors(GC/FPD/NPD) <br /> [Note: Organophosphorus pesticides are responsive to flame photometric and nitrogen phosphorus (alkali <br /> flame ionization)detection. Most of these compounds can be analyzed at concentrations of 50 to 500 ng/mL <br /> using either of these detectors.] <br /> 12.2.1 Procedures given in Section 12.1.1 through 12.1.9 and Section 12.1.13 through 12.1.14 apply, except <br /> for the selection of surrogates. <br /> 12.2.2 Use tributylphosphate, triphenylphosphate, or other suitable compound(s) as surrogates to verify <br /> extraction efficiency and to determine RRTs. <br /> 12.3 Analysis of Carbamate and Urea Pesticides by Capillary Gas Chromatography with Nitrogen- <br /> Phosphorus Detector <br /> 12.3.1 Trazine, carbamate, and urea pesticides may be determined by capillary GC (1313-5, DB-17, or <br /> DB-1701 stationary phase)using nitrogen-phosphorus detection or MS-SIM with detection limits in the 0.05 to <br /> 0.2 pL/mL range. Procedures given in Section 12.1.1 through 12.1.9 and Section 12.1.13 through 12.1.14 apply, <br /> except for the selection of surrogates,detector,and make up gas. <br /> 12.3.2 Thermal degradation may be minimized by reducing the injector temperature to 200°C. HPLC may <br /> also be used,but detection limits will be higher(1 to 5µg/mL). <br /> 12.3.3 N-methyl carbamates may be determined using reverse-phase high performance liquid <br /> chromatography (HPLC) (C-18) (Section 12.4) and post-column derivatization with o-phthaldehyde and <br /> fluorescence detection(EPA Method 531). Detection limits of 0.01 to 0.1 ,gg/mL can be achieved. <br /> 12.4 Analysis of Carbamate, Urea, Pyrethroid, and Phenolic Pesticides by High Performance Liquid <br /> Chromatography(HPLC) <br /> [Note: Many carbamate pesticides, urea pesticides,pyrethrins,phenols, and other polar pesticides may be <br /> analyzed by high HPLC with fixed or variable wavelength UV detection. Either reversed phase or normal <br /> phase chromatography may be used. Detection limits are 0.2 to 10,ug/mL of extract.] <br /> 12.4.1 Select HPLC column(i.e.,Zorbax-SIL,46-mm I.D.x 25-cm,or p-Bondapak C18,3.9-mm x 30-cm, <br /> or equivalent). <br /> January 1999 Compendium of MethodsJor Toxic Organic Air Pollutants Page 10A-11 <br />