## 3 Results and Discussion
### Spectral Information of Maple Syrup Samples  
The characteristic FT-IR absorption spectra of traditional maple syrup, BBL maple syrup, and corn syrup (as an example of table syrups) and their corresponding band assignments for specific functional groups are shown in Figure 3a. Key absorbance signals included the band at 2929 cm\({}^{-1}\) associated with C-H stretching of the CH2 group in carbohydrates [8]. The band at 1637 cm\({}^{-1}\) may be mainly related to O-H bonding in water, with minor contributions to C-O stretching in saccharides [34]. The band at 1415 cm\({}^{-1}\) related to C-H bending [35] and the band at 1327 cm\({}^{-1}\) related to O-H bending of the C-OH  
Figure 2: Representative GC-MS chromatograms of volatile compound profiles for BBL maple syrup, suspicious BBL maple syrup and traditional maple syrup. group might attribute to organic acids. The band at 1110 cm\({}^{-1}\) was associated with C-O stretching of C-O-C linkage, which could be the glycosidic linkage in sucrose. The bands at 1042 and 990 cm\({}^{-1}\) were associated with C-O stretching in the C-OH group and C-C stretching in carbohydrates, and the band at 927 cm\({}^{-1}\) was related to C-H stretching [8]. The broadband located around 3600-3000 cm\({}^{-1}\) was mainly related to O-H bonds stretching in water, which has been reported previously as the major infrared bands of water located at 3490 and 3280 cm\({}^{-1}\) for O-H stretching [36; 37]. The range from 1200 to 800 cm\({}^{-1}\) could be assigned to the carbohydrates absorption region, mainly related to sucrose, fructose, and glucose absorption bands [8; 36]. The characteristic Raman signal of traditional maple syrup, BBL maple syrup, and corn syrup (as an example of table syrups) and their corresponding band assignments for specific functional groups are shown in Figure 3b. The major bands in the Raman spectra were centered in the range of 500-1500 cm\({}^{-1}\). One major band at 522 cm\({}^{-1}\) was associated with the deformation of C-C-O and C-C-C [38], while another major band at 542 cm\({}^{-1}\) is related to an unassigned vibration [8]. The band at 590 cm\({}^{-1}\) is associated with skeletal vibration [38], and the band at 629 cm\({}^{-1}\) corresponded with sugar ring deformation [28]. The minor band at 740 cm\({}^{-1}\) could be due to C-C, C-O stretching in the carbohydrate molecules [13]. The dominant peak at 835 cm\({}^{-1}\) is responsible for C-C stretching, which is an intense band found in sucrose [39]. The high Raman signal at 835 cm\({}^{-1}\) band is associated with the high sucrose content (-68%) in maple syrup [4]. Both peaks at 923 and 1067 cm\({}^{-1}\) are responsible for the combination of vibration C-H bending, especially the C-H bond at C1 position and COH bending [8]. The peak at 1127 cm\({}^{-1}\) could be due to the deformation of C-O-H, as well as the vibration of C-N, which is found in protein or amino acid [28; 38]. The band at 1265 cm\({}^{-1}\) is associated with the deformation of C-C-H, O-C-H,  
Figure 3: (**a**)FT-IR spectrum band positions and corresponding wavenumbers of traditional maple syrup, BBL maple syrup, and corn syrup at a frequency of 4000–700 cm\({}^{-1}\) collected using a portable five-reflections ZnSe crystal ATR system. (**b**) Raman spectrum, band positions and corresponding wavenumbers of traditional maple syrup, BBL maple syrup and corn syrup at a frequency of 350–1500 cm\({}^{-1}\) collected using benchtop Raman with 1064 nm excitation laser. C-O-H, and the vibration of Amide III, which is a peptide bond, and the band at 1460 cm\({}^{-1}\) is related to the symmetric deformation in the plane of CH2 [38]. In both FT-IR and Raman spectra, corn syrup was easily differentiated from traditional maple syrup and BBL maple syrup using only visual assessment due to maple syrups' unique patterns. However, between traditional maple syrup and BBL maple syrup, the spectral differences were not noticeable via visual evaluation due to their similarity.