Detection of nanomaterials released from polymer nanocomposites using single particle inductively coupled plasma mass spectrometry

Transcription

1 Detection of nanomaterials released from polymer nanocomposites using single particle inductively coupled plasma mass spectrometry H O W A R D F A I R B R O T H E R 1, J A M E S R A N V I L L E 2, R O B E R T R E E D 2, D A V I D G O O D W I N 1, K R I S M A R S H 1, R O N L A K O N E 1, J J W A N G 2 1 ) J O H N S H O P K I N S U N I V E R S I T Y 2 ) C O L O R A D O S C H O O L O F M I N E S S N O N O V E M B E R 5,

2 Potential for release to environment 2 Incineration Discharge/ waste Wear/ Abrasion Weathering Biodegradation UV Washing

3 Predicted environmental concentrations (surface water) 3 Gottschalk et al., Environmental Pollution (2013)

4 Why study CNT release? Risk = Hazard x Exposure 4 We wish to assess the exposure from product release Motivates need for development of analytical methods

5 ICP-MS 5 Benefits of ICP-MS analysis Selectivity (Element specific detection) Sensitivity (ppt) Image:

6 Nanoparticulate sample Metals in solution spicpms concept Sample Plasma Result 6 Dwell time Intensity, counts Dwell time Constant signal Sample containing dissolved metals constant stream of charged ions time Dwell time (3 to 10 ms) Dwell time Individual pulses Intensity, counts Sample containing inorganic nanoparticles, at very low concentration pulses of charged ions Mitrano et al, Environmental Toxicology and Chemistry, 2012 time

7 Detection and quantification of CNT release from simulated nanocomposite 7 Challenge Detection of CNTs released to the environment Engineered carbon is very difficult to differentiate from natural carbon background Very low (ng/l) concentrations of CNTs expected

8 Residual metal in CNTs Synthesized by chemical vapor deposition Uses metal NPs as catalysts Intercalated into carbon structure 8 Carbon Solutions Can spicpms detect CNTs using residual metal? Pumera, Langmuir 2007, 23,

9 Materials and methods CNTs analyzed: Nanostructured and Amorphous Materials (NanoAmor) Carbon Solutions Southwest Nanotechnologies Nanolabs Unidym Suspended with 1% Triton-X surfactant, diluted ~1:1,000,000 in nanopure water for spicpms Instrument: Perkin Elmer NexION 300q ICP-MS 9

10 Analysis of Fe-containing CNTs? Unidym and NanoLabs CNT contain Fe ICP-MS analysis of Fe can be difficult due to interferences Fe isotope 54 Fe Fe Fe Fe % abundance Interference on m/z 56: 40 Ar 16 O + and 40 Ca 16 O + Interference on m/z 54: 40 Ar 14 N + and 40 Ca 14 N + Interference on m/z 57: 40 Ar 16 OH + and 40 Ca 16 OH + Source: 10 ICP-MS response ( 57 Fe counts) NanoLabs Time (sec)

11 Characterization of CNTs 11 CNT brand Type Length (nm) Diameter (nm) Metal content (reported) Metal content by EDS Nanostructured and Amorphous Material (NanoAmor) SWNT Co 0.6%, Mo 0.1 %, Mg 1.2% (at%) Co 0.5%, Mo 0.1%, Fe 0.1% (at%) Carbon Solutions SWNT 1800± ±1.8 Ni, Y (1-30 wt%) Ni 19.4%, Y 6.0% (at%) Southwest Nanotechnologies SWNT 578± ±0.1 Co, Mo (1-15 wt%) Co 1.1%, Mo 3.7% (at%) Reed et al, Environ. Sci.: Processes Impacts, 2013, 15,

12 Initial tests, NanoAmor CNT NanoAmor, Mo NanoAmor, Co59 ICP-MS Response (counts) ICP-MS Response (counts) Time (sec) Time (sec) Reed et al, Environ. Sci.: Processes Impacts, 2013, 15,

13 Initial tests, Carbon Solutions CNT Carbon Solutions, Ni Carbon Solutions, Y89 ICP-MS Response (counts) ICP-MS Response (counts) Time (sec) Time (sec) Reed et al, Environ. Sci.: Processes Impacts, 2013, 15,

14 Preparing CNT-chitosan nanocomposites for release study Solvent evaporation in an aluminum cup Creates a chitosan/cnt coupon 14 CNT Loading

15 Solids were left in nanopure water for seven days Supernatant was analyzed by spicpms for detection/ quantification of CNT release Nanocomposites in water 15

16 Release study, varying mass loading 16 ICP-MS response ( 89 Y counts) 50 2% 0.5% CNT CNT Time (sec) Reed et al, Environ. Sci.: Processes Impacts, 2013, 15,

17 CNT detection events vs mass loading Cut-off = 20 counts Pulses Loading (Mass% CNT) Reed et al, Environ. Sci.: Processes Impacts, 2013, 15,

18 Detection yes, quantification work in progress Demonstrated ability to detect CNTs using residual metal Useful for tracking released CNTs Improve quantification by developing statistically robust cut-off criterion 18 Improvement may come from improved spicpms methods (microsecond spicpms) lowered background reduced potential for coincidence Multi-element detection Manuel Montano presentation of microsecond spipms at 2:55 on Tuesday Santa Rosa room

19 JHU Ron Lankone Acknowledgements David Goodwin Funding Kris Marsh - LCNano CSM CBET Manuel Montano Robert Reed

20 Questions? Thank you for your attention! 20