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ENVIRONMENTAL ANALYSIS I. Solid Phase Extraction

ENVIRONMENTAL ANALYSIS I. Solid Phase Extraction. example - triazines. Example: Atrazine. Atrazine Structure. Atrazine from Water Apolar Retention. Column: C18, 1g / 6mL 1. Sample pre-treatment: none 2. Solvation: 10mL MeOH 3. Equilibration: 10mL water 4: Sample: 500mL aqueous

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ENVIRONMENTAL ANALYSIS I. Solid Phase Extraction

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  1. ENVIRONMENTALANALYSISI. Solid Phase Extraction example - triazines

  2. Example: Atrazine Atrazine Structure

  3. Atrazine from WaterApolar Retention Column: C18, 1g / 6mL 1. Sample pre-treatment: none 2. Solvation: 10mL MeOH 3. Equilibration: 10mL water 4: Sample: 500mL aqueous 5: Wash: 10mL water; dry: 30min 6: Elution: 2 x 4 mL acetone

  4. Atrazine from Corn OilPolar Retention Column: DIOL, 500mg / 6mL 1. 2mL oil  dilute w. 18mL of nC6 2. Solvation: 6mL nC6 3. Equilibration: none 4. Sample: 20mL (diluted) 5. Wash: 2mL nC6 6. Elution: 1mL methanol

  5. Atrazine from SoybeansCation-Exchange Mechanism Column: SCX, 500mg / 6mL 1. 5g sample + 10mL ACN  homogenize, filter; dilute 5mL filtrate w. 20mL 1% AcOH 2. Solvation: 3mL methanol 3. Equilibration: 6mL 1% AcOH 4. Sample: 25mL (diluted) 5. Wash: 1mL of 1% AcOH and 1ml of ACN 6. Elution: 2mL of 1:1 ACN - 0.1M K2HPO4

  6. ISOLUTE Triazine Traditionally, problems have been reported in achieving high, reproducible recoveries of triazine herbicides, when extracting from water samples. This is particularly true for the polar metabolites desethyl and desisopropyl atrazine (see figure) due to their reduced non-polar functionality. IST have introduced a column specifically for triazine analysis, which is QC tested in house to ensure good recoveries of the polar metabolites.

  7. Triazine Structures

  8. Extraction of Triazines from Water Samples Extraction of the triazines from river water was performed using IST’s large volume extraction cap. This is designed for direct loading of the sample from collection vessel to SPE column, and can be used in the field. Loosened cap  To Vacuum

  9. SPE of Triazines Column ISOLUTE® Triazine 1g / 6ml Solvation Methanol (2 x 5 ml) Equilibration Water (2 x 5 ml) Sample River water (500 ml) spiked with application 10 ng / ml of 4 triazines Interference Water (10 ml) elution Dry 30 mins at -20“ Hg vacuum Analyte elution 2 x 1.5 ml ethyl acetate Evaporate to dryness and reconstitute with 500l acetonitrile

  10. HPLC Chromatogram HPLC column: Kromasil CN, 15cm x 4.6mm x 5mMobile phase: 15% acetonitrile, 85% Trichloroacetic acid (0.05%) pH 3. Flow rate 1 ml / min. 5 l injected.254nm.

  11. Results Analyte% Recovery (w. depthfilter) Desethyl atrazine 94 (100) Desisopropyl atrazine 85 (86) Simazine 80 (94) Propazine 91 (94) N.B. The river water sample contained 0.4mg/L suspended solids. Use of the depth filter improved recovery, reproducibility and flow characteristics.

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