A Review of The X-ray Powder Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) Characterization for Essential Oil

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International Journal of Advanced Research in Technology and Innovation e-ISSN: 2682-8324 | Vol. 3, No. 4, 1-4, 2021 http://myjms.mohe.gov.my/index.php/ijarti

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A Review of The X-ray Powder Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) Characterization for

Essential Oil

Nur Sakinah Mahazir¹, Siti Amira Othman^1*

1 Faculty of Applied Sciences and Technology, University Tun Hussein Onn Malaysia, Pagoh, Johor

*Corresponding Author: [email protected] Accepted: 15 November 2021 | Published: 1 December 2021

DOI:https://doi.org/10.55057/ijarti.2021.3.4.1

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Abstract: The samples that were analysed using FTIR and XRD are reviewed in this study.

Genuine commercial essential oils as well as essential oils mixed with nanoparticles were employed. According to FTIR studies, commercial essential oils only comprise 20% true essential oil and are mixed with impurities. Aside from that, each essential oil contains molecules such as C=C, C=O, and –OH. The creation of an inclusion complex between thymus essential oil (TEO) and nanoparticles (NS) components was revealed by XRD analysis. GEO composite sheets including PVA/GA/CS were found to be potential wound dressing and food packaging solutions.

Keywords: XRD, FTIR, essential oil

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1. Several Types of Essential Oil Damask Rose

Rosa damascena is a member of the Rosa genus. Also known as the oil-bearing rose or Damask rose. Due to its wide range of applications in fragrance, pharmaceuticals, cosmetics, and the food industry, essential rose from rose has a high economic value (Cebi et al., 2021). There are no extra chemicals or contaminants in genuine R. damascene essential oil.

The authentic and commercial samples of R. damascene essential oil utilised in this investigation are (n=12) and (n=20) correspondingly. All materials were held at room temperature (25°C) for 30 minutes prior to FTIR analysis, and all spectral capture was done with an ATR accessory (single-bounce). The resolution of the spectral measuring parameters is 4 cm^-1 and the accumulation is 16 scans. With the use of a Pasteur pipette, each sample was deposited on a diamond ATR crystal. For each spectral acquisition, the ATR crystal was cleaned with ethanol (80% v/v).

Cinnamon

Cinnamon essential oil nanocapsules and the CEO are tremendously used. For cut creation, CEO-NPs were mixed individually with potassium bromide (KBr) is rubbed and pressed. The spectra were obtained using fourier transformation infrared spectroscopy (FTIR) with a scanning number of 32 and a determination of 4 cm in the infrared region of 400^-1 to 4000 cm^-

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Thymus Essential Oil (TEO)

The TEO-(nanoparticle, Ns) were created using the freeze drying method. TEO was added in varied ratios (w/w) of 1:2, 1:4, 1:6, and 1:8 to 200 mg of NS dissolved in 10 ml of distilled water (TEO: NS).The mixtures were agitated for 24 hours at room temperature in the dark before being sonicated for 10 minutes.To compare particle size, a group of samples were prepared without sonication and centrifuged at 2000 rpm for 10 minutes. The complex TEO- containing supernatant was freeze dried for 24 hours at -40ôC. TEO, NS, and TEO-NS were studied with an X-ray diffractometer at a voltage of 40 kV and a current of 30 mA. Cu Kα as a radiation source (= 1.54A). 2θ = 10-60ô and 0.05ô were the operating range and step size, respectively.

Ginger Essential Oil (GEO)

XRD pattern analysis was used to determine the crystalline nature of the PVA/GA/CS and GEO integrated PVA/GA/CS composited films. Cu Kα radiation( λ = 1.5406 nm) was used to analyse the samples at ambient temperature across the 2θ of 10 and 90^o at a scanning speed of 1.2^o /min. The prepared composite films were vacuum dried at 60°C before the assay (Amalraj et al., 2020).

2. Results and Discussion

FTIR for Lemongrass Essential Oil

The C=O absorption band at 1736 cm^-1 in the spectra of lemongrass essential oil is characteristic of its primary chemical group and ingredient citral (3,7-dimethyl 2,6-octadienal) (Martins et al., 2021).

The absorption band at 1736 cm^-1 was utilised as a reference to assess the presence of lemongrass essential in micro particles. The existence of an absorption band in the expanded spectral region proved that all of the samples M1, M2, and M3 contained lemongrass essential oil.

FTIR for Damask Rose Essential Oil

Significant vibrational bands were found in the FTIR spectra of Damask Rose essential oil at 3345, 2960, 2922, 2853, 1668, 1515, 1451, 1377, 1260, 1235, 1053, 1004 and 829 cm^-1. The stretching vibration of the OH functional group of alcohol might be ascribed to the spectral band at 3345 cm^-1 The C=C-C ring vibrations of volatile substances are responsible for point 2960 cm^-1. The spectra of the Damask Rose essential oil sample and the commercial sample overlapped and were recorded. Only 20% of commercial samples were grouped between authentic samples based on FTIR data. In other words, the rest of the commercial essential oil formulations had contaminants or alien compounds.

FTIR for Thymus Vulgaris L. Essential Oil

The carbonate band confirmed the carbonate bonds between two Cyclodextrin (CD) monomers at roughly 1780 cm^-1, according to the characteristics of nanoparticles (NS). Thymus essential oil (TEO)'s characteristic peaks were found at 3405 cm^-1 for –OH stretching, 1421 cm^-1 for – OH bending vibration, and 1228 cm^-1 for C-O bending vibration. The conjugated double bond of the rings related to TEO phenolic compounds such as thymol and carvacrol is correlated with the absorption peak at 1620 cm^-1. Peaks 1587 cm^-1, 1516 cm^-1 and 1458 cm^-1 corresponded to the thymol characteristic peaks and could be attributed to the stretching of the -CH2- group (Rezaei et al., 2021). Peaks at 1587 cm^-1 and 1421 cm^-1 were shifted/broadened in TEO-NS

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and emerged at 1593 cm^-1 and 1418 cm^-1 related to stretching of -CH2- and –OH bending vibrations, respectively.

FTIR for Cinnamon Essential Oil

The stretching vibrations of C=O, C=C, and –OH of aromatic compounds such as aldehydes, phenols, and ketone monomer are corresponded to the adsorption peaks of cinnamon essential oil (CEO) at 1679cm^-1, 1679cm^-1, 1450cm^-1and 1295cm^-1 (Yang et al., 2021).

In the case of CEO-NPs, the absorption peak of C=O of CEO was weakened, and it had migrated to a low wave number direction at 1672 cm^-1. It's possible that this has anything to do with the development of intermolecular hydrogen bonds. Furthermore, CEO absorption in the nanocapsules stopped at 2918, 2849, 972, and 689 cm ^-1. The absorbance at 1123 cm-1 was similarly reduced.

Table 1: Summary of XRD results

Essential oil Summary References

Thymus essential oil Sharp peaks were found in the NS XRD pattern at 28˚, 25˚, 22.5˚, 20˚, 17˚, 16˚, and 12˚ (2θ).

These revealed that NS has a crystalline structure, whereas TEO has an amorphous structure with a prominent distinctive peak at 29 ˚ on the 2θ scale.

(Rezaei et al., 2021)

Ginger essential oil PVA/GA and CS XRD patterns around 20˚

indicate amorphous nature with substantial crystallinity of PVA, GA, and CS. The peak around 20˚ grew broader and less intense after incorporating GEO and PVA, GA and CS composite films, indicating disruption of the PVA/GA/CS composite film structure.

(Amalraj et al., 2020)

3. Conclusion

Essential oils are now employed as a therapeutic and a medicine. Many plant essential oils include aromatic compounds and can be used to flavour meals. Microwave aided extraction (MAE), distillation, and drying methods have been used to extract plant essential oil (Balti et al., 2018) (Yang et al., 2021). (Liu et al., 2021). Impurities and other compounds are mixed in with true essential oil in commercial essential oils. Aldehydes and ketone monomers are among the compounds found in essential oils. These can be seen using FTIR with a specific peak point that corresponds to a specific functional group.

Acknowledgement

Authors would like to thank Universiti Tun Hussein Onn Malaysia for make this research possible.

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