Figure 2.

Fourier transform infrared spectrum of gastric aspirate from an infant born in week 31. The fingerprint region is the most informative region in the spectrum for analysis of biological material. Each peak denotes a composition of chemical bonds. The spectrum can be further differentiated to obtain underlying signals. To diagnose bronchopulmonary dysplasia, calculations as described in the manuscript are needed. The infant is not included in the actual study. Dipalmitoyl‐phosphatidylcholine the most surface‐active part of surfactant is expressed in the high peak at 1740 cm⁻¹ together with other phospholipids. Therefore, the infant may have mature lungs.