Andrei Medvedovici, Florina Micăle, Florentin Tache

Transcription

1 Andrei Medvedovici, Florina Micăle, Florentin Tache Department of Analytical Chemistry, Faculty of Chemistry, University of Bucharest, # Panduri Ave., Bucharest , Romania; Fax no ; avmedved@yahoo.com INTERNATINAL WRKSHP Food Chemistry & Engineering May 15 th 2015, Constanta, Romania

2 " NASA's Spitzer Space Telescope is the first telescope to see polycyclic aromatic hydrocarbons so early -10 billion years further back in time than seen previously. Spitzer detected these molecules in galaxies when our universe was one-fourth of its current age of about 14 billion years. These large molecules, are among the building blocks of life."

3 Definition - Hydrocarbons with fused aromatic rings. Sources - Biogenic, Petrogenic, Pyrogenic (natural & anthropogenic) Generation - 2 deficient combustion of organic matter. ccurrence - Air, Water, Soil, Dry/Wet deposition on plants. Exposure - Direct contact, breathing, eating, drinking. Impact - Toxic, Carcinogenic, Mutagenic

4 Selectivity! Selectivity! Solvent(s) pump Selectivity! Cartridge (adsorbent) C 2 (l) Selectivity! Cooler Modifier pump Selectivity! C 2 pump

5 Recovery (%) TGs F luoranthene B enzo[a]pyrene Density (g/ml)

6 Recovery (%) TGs Fluoranthene Benzo[a]pyrene ml C6/DCM 1: mL C6/DCM 1: ml MeH Benzo[a]pyrene Fluoranthene TGs Sandra P, Medvedovici A, Kot A, David F, in Packed Column Supercritical Fluid Chromatography, (C. Berger; K. Anton Eds.) Marcel Dekker Publishing Inc., pg (1997).

7 CH 3 Si Si CH 3... N H Ag + Special Adsorbents: Metal Ion Embedded (for - interactions)

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10 Agilent Technologies: Application Note EN (2008). Si Si Si Si Si Si

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12 Characteristics ACN EL CAS no Type of solvent Polar aprotic Polar protic Molecular weight Molecular dipole moment (D) Dielectric constant Hansen solubility parameters Dispersive (δd) Polar (δp) Hydrogen bonding (δh) Hildebrand solubility parameter (δt) Boiling point ( o C) Melting point ( o C) Density (g/cm 3 ) Log K o/w Water solubility Miscible Miscible Viscosity/25 o C (cps) Vapor pressure (kpa/20 o C) Flash point ( o C) Auto ignition temperature ( o C) Lower flammable limit (LFL) (%) Upper flammable limit (UFL) (%) ral LD50 rat (mg/kg) Dermal LD50 rabbit (mg/kg) 980 >5000 Acute LC50 Daphnia 48 hrs (mg/ml) HMIS Health 2 1 HMIS Flammability 3 2 HMIS Physical hazards 0 0 NFPA Rating Health 2 2 NFPA Rating Fire 3 2 NFPA Rating Safety 2 0 Exempt VC (acc. 40 CFR ) No Yes Biodegradability ~ 40%/10 days Readily biodegradable

13 Backpressure Ratio EL/ACN y = 0.858e x R 2 = % rganic Solvent

14 y = Ln(x) R 2 = cut-off %EL

15 25.00 ACN/water=70/30 EL/water=50/ HETP ( m) m u (cm/min)

16 Zorbax Eclipse XDB C18 (Agilent Technologies, PN ), 100 mm L 2.1 mm i.d. 3.5 µm d.p. Flow rate of 0.3 mlmin -1 ; Temperature: 25 o C A B C D E F G H A B D C E F G H k k % ACN % EL naphthalene A; acenaphtylene B; fluorene C; acenaphtene D; phenanthrene E; anthracene F; fluoranthene G; pyrene H; chrysene I; benzo(a)anthracene J; benzo(b)fluoranthene K; benzo(k)fluoranthene L; benzo(a)pyrene M; dibenzo(a,h)anthracene N; benzo(g,h,i)perylene ; indeno(1,2,3-c,d)pyrene - P

17 naphthalene A; acenaphtylene B; fluorene C; acenaphtene D; phenanthrene E; anthracene F; fluoranthene G; pyrene H; chrysene I; benzo(a)anthracene J; benzo(b)fluoranthene K; benzo(k)fluoranthene L; benzo(a)pyrene M; dibenzo(a,h)anthracene N; benzo(g,h,i)perylene ; indeno(1,2,3-c,d)pyrene - P I J K L M N P I J K M L P N k k % ACN % EL

18 log k log k EL EL B log(% EL) ACN ACN B log(% ACN ) A EL A ACN (% EL) ACN EL B (% ACN) 10 B A ACN B A EL EL y = x R 2 = 1 % EL % ACN

19 naphthalene A; acenaphtylene B; fluorene C; acenaphtene D; phenanthrene E; anthracene F; fluoranthene G; pyrene H; chrysene I; benzo(a)anthracene J; benzo(b)fluoranthene K; benzo(k)fluoranthene L; benzo(a)pyrene M; dibenzo(a,h)anthracene N; benzo(g,h,i)perylene ; indeno(1,2,3-c,d)pyrene - P mau N or m ali ze d A A B B C D E D C E F F G H I J K L M min G H I J K L ACN / Water = 62.5 / 37.5 % M EL / Water = 47.5 / 52.5 % P N N P min

20 2.5 2 y = x R 2 = Log(Total run time) y = x R 2 = EL ACN Log(% rganic modifier)

21 ACN/water = 70/30 (v/v) EL/water = 45/45 (v/v) Compound H 0 S 0 G 0 (25 B A r C) H 0 S 0 G 0 (25 xy KJmol -1 K -1 Jmol -1 K -1 KJmol -1 K -1 B A r C) xy KJmol -1 K -1 Jmol -1 K -1 KJmol -1 K -1 A B C D E F G H I J K L M N P naphthalene A; acenaphtylene B; fluorene C; acenaphtene D; phenanthrene E; anthracene F; fluoranthene G; pyrene H; chrysene I; benzo(a)anthracene J; benzo(b)fluoranthene K; benzo(k)fluoranthene L; benzo(a)pyrene M; dibenzo(a,h)anthracene N; benzo(g,h,i)perylene ; indeno(1,2,3-c,d)pyrene - P

22 0-5 y = x r xy = S S H H 0

23 Physico-chemical descriptors: Molecular weight (M w ); Solute's solubility in water (S); Logarithm of the partition coefficient between n-octanol and water (log P). Geometrical descriptors: van der Waals volume (V w ); van der Waals surface area (A w ). Molecular shape descriptors: Length to breadth ratio - L/B; Molecular topology: Connectivity index - ; Correlation factor - F. rganic Descriptor M w V w log P S F L/B Modifier Function M w =f(log k) V w =f(log k) Log P=f(log k) Log S=f(log k) =f(log k) F=f(log k) L/B=f(log k) ACN Mean r xy s EL Mean r xy s

24 mau F Column: Ultra Biphenyl, 150 mm L x 2.1 mm i.d. x 3 m d.p. H 2 /ACN: 50/50 to 20/80 in 15 min.; 0.3 ml/min; 25 o C; 0 A B D C E H G K + J M I L Si Si Si N P Si min naphthalene A; acenaphtylene B; fluorene C; acenaphtene D; phenanthrene E; anthracene F; fluoranthene G; pyrene H; chrysene I; benzo(a)anthracene J; benzo(b)fluoranthene K; benzo(k)fluoranthene L; benzo(a)pyrene M; dibenzo(a,h)anthracene N; benzo(g,h,i)perylene ; indeno(1,2,3-c,d)pyrene - P

25 mau F Column: Ultra Biphenyl, 150 mm L x 2.1 mm i.d. x 3 m d.p. H 2 /MeH: 30/70 to 0/100 in 20 min.; 0.2 ml/min; 25 o C; C E G H K J I + L M N P A B D min naphthalene A; acenaphtylene B; fluorene C; acenaphtene D; phenanthrene E; anthracene F; fluoranthene G; pyrene H; chrysene I; benzo(a)anthracene J; benzo(b)fluoranthene K; benzo(k)fluoranthene L; benzo(a)pyrene M; dibenzo(a,h)anthracene N; benzo(g,h,i)perylene ; indeno(1,2,3-c,d)pyrene - P

26 1. The assay of PAHs in natural/artificial matrices is still of high importance and actuality. 2. Highly lipophilic matrices are extremely challenging for sample preparation procedures of PAHs for chromatographic analysis. 3. Replacement of ACN by EL in LC mobile phases does not essentially change retention, selectivity and interactions with the S. Ph. While the increased pressure drop may be sustained by means of UP/UHP-LC approaches, detectability remains a major concern. 4. Involvement of interactions in the LC chromatographic mechanism of PAHs does not necessarily increase separation selectivity.

27 Author acknowledges the financial support given through the Romanian project PNII_ID_PCE_2011_3_0152.