Free radical scavenging and formation by multi-walled carbon nanotubes in cell free conditions and in human bronchial epithelial cells

Table 1 Test material information

Material	Type	Name	Producer/distributor	Average diameter (nm)^a	Average length (μm)^a	Major elements^b	Minor elements^c	Specific surface area (m²/g)^d
Asbestos	Crocidolite	-	UICC	180	4.6	Fe, Si, Na, Mg, Ca, O		8.3^e
Glass wool	Insulation fibre	MMVF10/Manville 901	Johns Manville, Denver, CO, USA	1100 ± 500	21 ±18	Si, Al, O, Na, Mg, K, Ca		1.07^f
MWCNT_LNL1	Long, needle-like	MWCNT-7	Mitsui & co, Ltd, Tokyo, Japan	74 ± 28	5.7 ± 3.7	C	< 0.5 wt% Na, Fe, Al, Mg, Ni	22 (29)
MWCNT_LNL2	Long, needle-like	NM-401	JRC, European Commission	64.2 ± 34.5	4.0 ± 2.4	C, residues of Si	< 0.6 wt% Na, Fe, Al, Ni, Mg	18 (31)
MWCNT_LT	Long, tangled	MWCNT 8-15 nm OD	Cheap Tubes Inc, Brattleboro, VT, USA	17 ± 7	0.5 ± 0.3	C residues of Ni, Fe	< 5 wt% Ni, Na, Fe, Al, Mg, Mn	75 (117)
MWCNT_SP	Short, purified	Baytubes C 150 HP	Bayer Material Science, Leverkusen, Germany	12.0 ± 7.0	0.4 ± 0.2	C, residues of Si, Co	< 3 wt% Mn, Mg, Al, Na, Ni, Fe	ND (189)
MWCNT_SNP	Short, non-purified	NM-400	JRC, European Commission	13.6 ± 3.7	0.8 ± 0.4	C, O, Si, Fe, Mg, Na	< 10 wt% Al, Fe, Na, Ni	254 (189)
Carbon black	Nano-sized	Printex 90	Evonik Industries AG, Essen, Germany	14	-	C, residues of Si	< 1 wt N, H^e	295-338^g

ND – not determined.
^aFor MWCNTs as detected in [33]; for other materials according to producer/distributer.
^bElemental analysis by TEM/EDS.
^cFrom [33] - ICP-MS analysis; in order of abundance from highest concentration to lowest.
^dFrom [33] – BET analysis (SAXS analysis), except for asbestos, glass wool and carbon black.
^eFrom [34].
^fFrom [35].
^gFrom [36].

ISSN: 1743-8977