]>

Table 2: Amount of Ni leached to the artificial sweat solution.

Sample Surface area (cm2) Worn Released nickel ($\mu$g$·$cm-2 per week) Number of groups appointed by discrimination analysis 1 0.25 Yes X 1 2 0.56 Yes 0.02 1 3 0.21 Yes 0.06 3 4 5.66 Yes 0.61 3 5 2.02 Yes 0.01 2 6 1.66 Yes 2.14 3 ka 0.79 Yes 0.71 1 kb 0.79 Yes 0.34 1 kx 0.79 Yes X 2 ky 0.79 Yes X 3 kz 0.79 Yes X 2 21m 1.50 No 0.01 1 21v 1.61 No 0.01 1 22m 0.92 No 0.04 1 22v 1.82 No 0.01 1 23m 1.34 No 0.01 1 23v 1.49 No 0.01 1 24m 0.61 No 0.02 1 24v 1.00 No 0.03 1 25m 0.72 No 0.07 1 25v 1.15 No 0.03 1 26m 2.44 No 0.01 2 26v 2.27 No 0.01 1

X: concentration of Ni in the artificial sweat was below the ICP OES limit of detection 5 $\mu$g$·$l-1.