MARKET FOCUSED - environmental ORGANOCHLORINE PESTICIDES

Transcription

1 TECHNICAL ARTICLE MARKET FOCUSED - environmental ORGANOCHLORINE PESTICIDES With the widespread use of pesticides, especially over the last 40 years, pesticide analysis is one of the most universal methods used in environmental laboratories around the world. Their persistence in the environment, and in some cases, their non-specific mode of action, has led to bans in many countries. This persistence has also resulted in the continuing need for monitoring of this class of compounds. Figure. Organochlorine Pesticide Structures US EPA 808A Method THE ANALYSIS The volatile nature of chlorinated pesticides naturally leads to gas chromatographic analysis. However, resolution requirements and breakdown performance criteria, especially for sample extracts containing high-boiling contaminants, are usually quite stringent. The USEPA has targeted 20 common chlorinated pesticides. Together with two internal standards this leads to a requirement to resolve 22 compounds (Figure ). Because of the screening nature of most environmental methods, there is always pressure in a lab to reduce analysis time and hence increase sample throughput. 2,4,5,-tetrachloro-meta-xylene (surrogate) p,p -DDE Heptachlor Endrin Aldehyde Alpha BHC Dieldrin Aldrin p,p -DDT Beta BHC Endrin Heptachlor epoxide Endosulfan Sulfate Gamma BHC p,p -DDD Gamma Chlordane Methoxychlor Delta BHC Endosulfan B Alpha Chlordane Endrine Ketone Endosulfan A Decachlorobiphenyl Surrogate

2 CHOICE OF CAPILLARY COLUMN There is a wide choice of capillary columns from SGE for the analysis of pesticides. It is common practice in labs around the world to split the sample after GC injection to two different capillary columns. These columns are usually of differing polarity and must show different retention times of analytes, preferably with some peak switching. It is common to quantify pesticide response on a non-polar column such as the SGE 5% phenyl BPX5 column or the SGE 00% methyl SolGel-ms column. The latter column, although custom designed as a low-bleed mass spec column, can be used successfully with all GC detectors. The second column used is one of differing polarity such as higher percentage phenyl column such as the 35% or 50% phenyl columns (BPX35 and BPX50, respectively). Using any of the columns described above, it is possible to analyse the 22 targeted compounds with excellent baseline resolution in under 22 minutes. This allows for greater throughput of samples. BPX5 5% phenyl (equiv) polysilphenylene-siloxane USEPA 808 Organochlorine Pesticide mix analyzed on the BPX5 column (Figure 2), shows an excellent separation of the components in less than 24 minutes. DDT (peak 8) and Methoxychlor (peak 20) show no on-column breakdown indicating the high degree of inertness of BPX5. Also note the exceptional bleed profile at 300 C. Figure 2. USEPA 808 Organochlorine Pesticide BPX5 replaces... DB-5 DB-5MS DB-5.25 XTI-5 Rtx-5ms Ultra-2 HP-5 HP-5MS HP5-TA SPB-5 MDN-5S CP-Sil 8CB Rtx-5Sil MS AT-5 CP-Sil 8CB MS Phase: BPX5, 0.25mm film Sample: 00ppm in Dichloromethane 30m x 0.25 mm ID Initial Temp: 0 C, min. Rate : 25 C/min to 0 C, Rate 2: 2 C/min to 20 C Rate 3: C/min to 30 C Final Temp: 30 C, min. Detector Type: Mass Spectrometer Carrier Gas: He, 0.5 psi Carrier Gas Flow:.0 ml/min. Constant Flow: On Average Linear Velocity: 3 cm/sec at 0 C Injection Mode: Split Split Ratio: 50: Injection Volume: ml Injection Temperature: 250 C Autosampler: No Liner Type: 4 mm ID Single Taper Liner Liner Part Number: Column Part Number: 0540 COMPONENTS. 2,4,5,-Tetrachlorometa-xylene. Heptachlor 9. gamma-chlordane 0. alpha-chlordane. Endosulfan A 4. Endrin 7. Endrin aldehyde 8. p, p' - DDT 9. Endosulfan Sulfate 2. Endrin ketone 22. Decachlorobiphenyl Exceptioanlly low bleed at 300 C

3 THE ADVANTAGE OF HIGH MAXIMUM TEMPERATURE COLUMNS The composition of sample extracts in an environmental lab can be extremely variable. From relatively clean water samples to extremely complex dirty soil samples. It is extremely useful to use a capillary column with a high maximum operating temperature. The column can then be baked out following deposition of semi and non-volatile residue material on the front end of the column. Once peak shape deteriorates, it is common practice to condition the column at the upper maximum temperature of the column for at least 0 minutes to remove this residue. If this fails to re-establish good chromatography then the front 0.5 meter of the SolGel-ms column can be cut and discarded. The second advantage of a column with a high maximum operating temperature is lower bleed at the upper method temperature. Thus, for example, if the upper maximum temperature of the column is 370 C, the bleed level at 300 C will be lower compared with a column with an upper maximum level of 320 C. This leads to better sensitivity for the higher maximum temperature column. Thermal stability of SGE stationary phases is excellent because of advanced polymer technology. For example, up to 30 C for BPX5, 35, 50 and up to 380 C for a SolGel-ms column. The very low bleed level at the maximum operating temperatures of these columns is a particularly advantageous to the chromatographer. Figure 3 shows the USEPA 808 pesticide mix analyzed using a SolGel-ms column. Note the superb bleeding profile at 300 C and separation of the components with no coelution s in less than minutes allowing multiple samples to be run in the laboratory. Again, SolGel-ms, like BPX5, BPX35 and BPX50 shows superior inertness with no-column breakdown of the susceptible DDT and Methoxychlor. Also note, 4 different elution orders making SolGel-ms an exceptional conformational column to that of BPX5. Figure 3 - SolGel-ms Column Phase: SolGel-ms, 0.25µm film Sample: 00ppm in Dichloromethane 30m x 0.25mm ID Initial Temp: 00 C, min Rate : 25 C/min to 0 C Rate 2: 2 C/min to 20 C Rate 3: C/min to 300 C Final Temp: 300 C, 5 min Detector Type: Mass Spectrometer Carrier Gas: He, 3. psi Carrier Gas Flow:.7mL/min Constant Flow: On Average Linear Velocity: 35cm/sec at 0 C Injection Mode: Splitless Purge on Time: 0.5min Purge On (Split) Vent Flow: 0mL/min Injection Volume: µl Injection Temp.: 250 C Autosampler: No Liner Type: 4mm ID SIngle Taper Liner Liner Part No.: Column Part No.: ms-novent Part no.:3400 HP5973 restrictor: 3409 Full Scan/SIM: Full Scan COMPONENTS. 2,4,5,-Tetrachlorometa-xylene. Heptachlor 9. gamma-chlordane 0. alpha-chlordane. Endosulfan A 4. Endrin 7. Endrin aldehyde 8. p, p' - DDT 9. Endosulfan Sulfate 2. Endrin ketone 22. Decachlorobiphenyl

4 BPX35 35% phenyl (equiv) polysilphenylene-siloxane Figure 3 shows the 808 USEPA pesticide mix analyzed on a BPX35 column. Note the brilliant peak shape, separation and the high degree of inertness with respect to DDT and Methoxychlor components. Also note the different order of elution of the components. BPX35 has two differences in the order of elution making it a perfect confirmation column for BPX5. It also has a very low bleed profile at 300 C. BPX35 replaces... DB-35 DB-35MS Rtx-35ms HP-35 HP-35MS SPB-35 MDN-35 AT-35 Figure 3. USEPA 808 Organochlorine Pesticide Phase: BPX35, 0.25 µm 30m x 0.25mm ID Initial Temp: 40 C for min Rate : 30 C/min to 90 C for 3min Rate 2: 0 C/min to 300 C for 5min Detector Type: Mass Spectrometer Carrier Gas: Helium at 0.0psi Carrier Gas Flow:.3 ml/min. Constant Flow: OnAv. Linear Velocity: 3 cm/sec at 40 C Injection Mode: Splitless Purge on Time: min Purge on (Split) Vent: 0mL/min Injection Volume: µl Injection Temp: 250 C Autosampler: No Detector: MSD Liner Type: 4 mm ID Double Taper Liner Column Part No: Detector: Mass Spectrometer COMPONENTS:. 2,4,5,-Tetrachloro -meta-xylene. Heptachlor 9. gamma Chlordane 0. alpha Chlordane. Endosulfan A 4. Endrin 7. Endrin Aldehyde 8. p, p' - DDT 9. Endosulfan Sulfate 2. Endrin Ketone 22. Decachlorobipheny minutes

5 BPX50 50% phenyl (equiv) polysilphenylene-siloxane In Figure 4, the USEPA 808 pesticide mix is analyzed on a BPX50 column. Note the superb bleed profile at 300 C and separation of the components in less than 22 minutes allowing multiple samples to be run in the laboratory. Again BPX50, like BPX5, SolGel-ms and BPX35, shows superior inertness with no on-column breakdown of the susceptible DDT and Methoxychlor. Figure 4. USEPA 808 Organochlorine Pesticide BPX50 replaces... OV-7 SP-2250 DB-7 DB-7MS DB-7ht Rtx-50 SPB-50 HP-50+ AT Phase: BPX50, 0.25 µm 30m x 0.25mm ID Injector Temp: 240 C Injection Volume: µl Autosampler Syringe: 5µL Fixed Needle (p/n 0080) Septa: Auto-Sep T (p/n 04882) Injection Type: Splitless Purge On Time: 0.5min Purge On (Spilt) Vent: 0mL/min Liner Type: Single taper (p/n 09207) Carrier Gas: Helium Constant Flow: On Pressure: 4.psi Column Flow:.3mL/min Linear Velocity: 40 C Initial Temp: 40 C for min Rate : 30 C/min to 90 C for 3min Rate 2: 0 C/min to 300 C for 5min Run Time: 25min Detector Type: 30 C Column Part No: COMPONENTS:. 2,4,5,-Tetrachloro - meta-xylene. Heptachlor 9. gamma Chlordane 0. alpha Chlordane 2. Endosulfan A 4. Endrin 7. Endrin Aldehyde 8. p, p' - DDT 9. Endosulfan Sulfate 2. Endrin Ketone 22. Decachlorobiphenyl minutes THE CHROMATOGRAPHY SGE s BPX5, SolGel-ms BPX35 and BPX50 phases show excellent inertness and do not have problems such as on column breakdown of methoxychlor and DDT. Indeed these three columns are exceptional for the analysis of the 22 chlorinated pesticides in the U.S. EPA methods 808 and 08. With at least two changes in the elution order of each column to that of BPX5, SolGel-ms, BPX35 and BPX50 columns are excellent confirmation columns for this type of analysis.

6 Ordering Information MARKET FOCUSED - environmental ORGANOCHLORINE PESTICIDES US EPA 808A Method ID(mm) Length Film Thickness Temperature Limits Part No. (mm) (m) (µm) ( C) BPX to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 350/ to 350/ to 30/ to 30/ to 30/ to 350/ to 350/ to 30/ to 350/ BPX to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ BPX to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ to 30/ SolGel-ms to 370/ to 370/ to 370/ to 370/ Publication No. TA-0079-C Rev:02 05/0 SGE Office Details SGE International Pty. Ltd. Toll Free: Tel: + (0) Fax: + (0) support@sge.com Web: SGE Incorporated (USA) Toll Free: Fax: usa@sge.com SGE Europe Ltd. (UK) Tel: +44 (0) Fax: +44 (0) uk@sge.com SGE (France) Sarl Tel: +33 (0) Fax: +33 (0) france@sge.com SGE (Italia) Srl. Tel: Fax: sge.italia@tin.it SGE Deutschland GmbH Tel: +49 (0) 8048 Fax: +49 (0) germany@sge.com SGE China Service Centre Tel: +8 (0) Fax: +8 (0) sge@bj.col.com.cn SGE Japan Inc. Tel: +8 (45) Fax: +8 (45) japan@sge.com SGE India Tel: +9 (022) Fax: +9 (022) sgeindia@vsnl.com