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. 2019 Nov 28;9:17850. doi: 10.1038/s41598-019-54360-2

Figure 16.

Figure 16

Thin-layer chromatograms of the tobacco samples with and without grey speckled leaves. Note: the left-hand sides of the figures show samples with grey speckles, while the right-hand sides show samples without grey speckles. (a,c) Thin-layer chromatograms without using H2SO4-EtOH, (b,d) Thin-layer chromatograms after using 5% H2SO4-EtOH. Conditions of (a,b) include a methylene chloride to methanol ratio of 5:1, while those in (c,d) include a methylene chloride: methanol: formic acid ratio of 5:1:0.1.).