1. Selective Detection of Dialkyl Phthalate by Molecular-sieving Sensor Naonobu Katada, Ken-ichi Fukuchi, Hideyuki Iwata, and Miki Niwa Tottori Univ., Fuji Electric Systems Co. Ltd.

2. DAP (dialkyl phthalate) = plasticizer Several  g m -3 of DAP gives damage for device on semiconductor surface Practical method for analysis of DAP  g m -3 Practical method for analysis of DAP in  g m -3 scale DOP (Dioctyl phthalate) DEHP (Bis-2-ethylhexylphthalate) Selective Detection of Dialkyl Phthalate by Molecular-sieving Sensor Naonobu Katada, Ken-ichi Fukuchi, Hideyuki Iwata, and Miki Niwa Tottori Univ., Fuji Electric Systems Co. Ltd. DBP (Dibutyl phthalate)

3. Sn 4+ SnO 2 semiconductor gas sensor O 2- Sn 4+ O 2- Sn 2+ O 2- Sn 4+ O 2- Sn 4+ O 2- Sn 4+ O 2- Sn 4+ O 2- Sn 4+ O 2- Sn 4+ O 2- Sn 4+ O 2- Sn 4+ O 2- Sn 4+ O 2- Sn 4+ O 2- Sn 4+ O 2- Sn 4+ O 2- Sn 4+ O 2- Sn 4+ O 2- Sn 4+ O 2- [ ] O 2- CH 4 CO 2 H2OH2OH2OH2O O 2- Electrical response to flammable compound Reactive for any of organic compound e- →e- →e- →e- →

4. There are other gases [toluene, isopropanol (IPA) and methylethyl ketone (MEK)] even in clean rooms. Selective detection is needed.

5. SnO 2 OO - Si(OCH 3 ) 4 Molecular sieving property + SnO 2 ’s Sensing Function O2O2O2O2 CHO SiO 2 layer CO 2, H 2 O CVD of SiO 2 in the presence of molecular template on SnO 2 surface J. Chem. Soc., Chem. Commun., 1995, 623.

6. Shape-selective adsorption Bull. Chem. Soc. Jpn., 78, 1425 (2005). Bull. Chem. Soc. Jpn., 78, 1425 (2005). Application to molecular-sieving sensor Sens. Actuators, B: Chem., 124, 398 (2007)

7. Aim of this study Application of molecular-sieving sensor to detection of DAP in the co-presence of toluene, IPA and MEK 1. Selective detection 2. Detection in  g m -3 scale 3. Prototype analyzer

8. Experimental Pd/SnO 2 powder, 20 m 2 g -1 Pt wire OOOO SnO 2 OO 100 nm 5 mm

9. He Sample Electric furnace ・ 1-Naphthaldehyde (template) was injected at 343 K ・ Si(OCH 3 ) 4 vapor was fed at 473 K ・ O 2 was fed at 673 K [Sens. Actuators, B: Chem., 124, 398 (2007)]Preparation

10. Air (100 cm 3 min -1 ) Electric resistance 0.5 mm 3 liquid 673 K Sensor measurements DOP / Toluene / Air Very low concentration of DOP / Air 1. Purification of DOP vapor was carried out; DOP liquid was heated at 383 K for 10 h in He flow. He was further flowed at room temperature for 24 h. DOP vapor was trapped to confirm the purity. 2. Thus prepared 4.8 mg m -3 DOP / air was diluted with pure air. 3. Equipment was heated and completely purged before the measurements.

11. DOP DBP DEHP Toluene IPA MEK All compounds detected Results and Discussion 0.5 mm 3 (as liquid) of Pd/SnO 2 (unmodified) sensor

12. DOP DBP DEHP Toluene IPA MEK DOP, DEHP, DBP --- selectively detected Toluene, MEK, IPA --- not detected SiO 2 /Pd/SnO 2 prepared using 1-NA template (molecular-sieving) sensor

13. Why? Detected by molecular-sieving sensor DOP, DEHP, DBP, linear alkane, ethanol Undetected Toluene, IPA, MEK, benzene, branched alkane, dimethyl phthalate (DMP)

14. Detection of  g m -3 of DOP Response of Pd/SnO 2 to steady flow of DOP/air -600060012001800 0 0.5 1 t / s R a /R 0 16 80 160 320 480 1600  g m -3 800 640 Detection limit = 500 Target =  g m -3 But the target is not far! Concentration of DOP using an adsorbent column is attempted.

15. vent sample adsorbent trap (porous polymer beads) furnace sensor 6-way valve O2O2 N2N2 flush by heating 300 cm 3 min -1 ×100 min

16. 05001000 0 1 2 3 4 5 t / s R a /R 8.0  g m -3 4.8  g m -3 Response by Pd/SnO 2 Air + DOP Air + Toluene (110 mg m -3 ) 05001000 0 1 2 3 4 5 t / s C DOP = 0 ppb R a /R (toluene only) 5 - 8  g m -3 DOP was detected.

17. 05001000 -0.1 0 0.1 0.2 0.3 0.4 t / s R a /R C DOP = 0 8.0  g m -3 4.8 mg m -3 Selective response by SiO 2 /Pd/SnO 2 Air + DOP 4.8  g m -3 8.0  g m -3 05001000 -0.1 0 0.1 0.2 0.3 0.4 t / s C DOP = 0 R a /R - 1 Air + Tol. (110 mg m -3 ) DOP (5 - 8  g m -3 ), detected Toluene (110,000  g m -3 ), not affecting Selective detection of pollutant at a low concentration + DOP

18. vent sample adsorbent trap (porous polymer beads) furnace sensor 6-way valve O2O2 N2N2 flush by heating 300 cm 3 min -1 ×100 min Complex valves N 2 and O 2 supply

19. vent sample (250 cm 3 min -1 ×40 min) adsorbent trap (MCM-41, mesoporous silica) furnace sensor Simple system 313 ～ 423 K ←→ 673 K

20. 35 cm 14 cm 40 cm Prototype analyzer

21. Adsorbent column Electric furnace Sensors Pump Electric tester Temperature controllers Sample air

22. A signal (noise) was observed by heating adsorbent. 5 - 8  g m -3 is safely detected in any case. -2000200400600 0 0.5 1 1.5 R a /R t / s 120  g m -3 C DOP = 0 2.4  g m -3 4.8  g m -3 24  g m -3 Collected for 40 min -1 Response by Pd/SnO 2 Air + DOP

23. -2000200400600 0 0.5 1 1.5 R a /R t / s 120  g m -3 C DOP = 0 2.4  g m -3 4.8  g m -3 24  g m -3 Collected for 40 min -1 Response by Pd/SnO 2 Air + DOP Air + Toluene (110 mg m -3 ) + DOP Unmodified sensor Continuous flow of toluene --> Complex change Signal by DOP hidden

24. Air + Toluene (110 mg m -3 ) + DOP Unmodified sensor Continuous flow of toluene --> Complex change Signal by DOP hidden Molecular-sieving sensor Response to toluene --> Suppressed 3 - 5  g m -3 of DOP detected Collected for 40 min -1 These are tentative results; final tests are now proceeding.

25. Conclusions 1. The molecular-sieving sensor (SiO 2 /Pd/SnO 2 ) detected ○ DOP, DEHP, DBP (ethanol, linear alkane) × Toluene, IPA, MEK (DMP, branched alkane) 2. About 5  g m -3 of DOP could be detected when a suitable adsorption - desorption system was combined. 3. 5  g m -3 of DOP was detected within 50 min in the co- presence of 110 mg m -3 of toluene by a prototype analyzer. Thank you for your kind attention!