rev 2 - introduction

[rmflight]

The section is well written but I am putting forth a suggestion as introductions are meant to start from a bigger picture before narrowing to the study context. Consider including a brief introduction on analytical techniques/instruments and the fact that a single technique may not achieve full characterization or analyses of (complex) samples. Thus, complementarity of techniques is becoming a powerful approach in the analyses of samples.

I think we didn't go "big picture" enough here? And I think they would like us to mention DI, LC, GC, NMR??

[rmflight]

Rebutted.