“…In the reviewed studies, FT-IR was performed either by measuring single particles, 16,54,59, via handheld FT-IR, 137,151 by a fiber optic, 152 by using mFT-IR, 18,29,35,42,51,78,100, by applying both techniques on separate instruments, 40,50,53,66,73,78,[213][214][215][216][217][218][219][220][221][222][223][224] or referenced to other publications. 225 Larger single particles were ground with potassium bromide (KBr) for transmission measurements, targeted via diffuse reflection, or by ATR measurements.…”