Fig. 3.

3D OrbiSIMS high-resolution negative polarity ion images, produced from the analysis of an individual human corneocyte skin layer, collected in vivo using a tape-stripping method. The primary ion beam was Ar₁₇₀₀⁺. The data shown are from tape strip 7, which represents the middle of the SC. The ion images illustrate the 2D spatial distribution for the following molecular ions: cholesterol sulfate (C₂₇H₄₅SO₄⁻) (A), lignoceric acid (C₂₄H₄₇O₂⁻) (B), pyrrolidone carboxylic acid (C₅H₆NO₃⁻) (C), and SLS (C₁₂H₂₅SO₄⁻) (D). All ion images have been normalized to the total ion image and their relative intensity scales set to 50% of the maximum.