Determination of Metal Impurities in Carbon Nanotubes Sampled Using Surface Wipes

Table 3

Metal concentrations of NIST 2483-CNT with microwave digestion (MD) and ultrasonic digestion (UD) methods in the presence of GhostWipes. The results are presented as mean (μg/g) and standard deviation of five independent determinations (nd = not detected due to blank correction; <LOD = below detection limit; n/a = not available).

Element	LOD (μg/g)		Mean ± STDEV (μg/g)
	MD	UD	Certified value	MD	UD
Boron	9.72	12.4	74.7
Aluminum	431	26.6		nd
Vanadium	0.17	0.18
Chromium	4.81	6.69	n/a
Manganese	3.87	0.25		nd	nd
Iron	383	247	n/a	nd	<LOD
Cobalt	2.43	0.13
Nickel	2.65	0.97	n/a	nd
Copper	7.54	2.52	186
Zinc	218	26.2	n/a	nd	nd
Arsenic	0.15	0.54	12.5
Molybdenum	2.71	5.96
Barium	1.19	0.32
Lanthanum	0.15	0.07
Gadolinium	0.04	0.06
Uranium	0.02	0.06	n/a

Yttrium LOD: 5.12 g/g (MD) and 3.0 g/g (UD).