b) illuminating {HEAD ~ the sample} within {TAIL ~ said test element} with light of NIR wavelengths, 
within
b ) illuminating { HEAD ~ the sample } within { TAIL ~ said test element } with light of NIR wavelengths ,
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH