Fig. 3

Calibration curves of naphthalene expressed in arbitrary units (AU) vs mass of naphthalene spiked on sorbent tubes. Error bars represent the difference between duplicates. In plot A the error bars are too small to be visible

Calibration curves of naphthalene expressed in arbitrary units (AU) vs mass of naphthalene spiked on sorbent tubes. Error bars represent the difference between duplicates. In plot A the error bars are too small to be visible