NSNatural Science2150-4091Scientific Research Publishing10.4236/ns.2021.133009NS-108040ArticlesBiomedical&Life Sciences Chemistry&Materials Science Earth&Environmental Sciences Medicine&Healthcare Physics&Mathematics Determination of Gum Arabic (<i>Acacia nilotica</i>) Constituents Using Laser Induced Breakdown Spectroscopy MashairAhmed Mohammed Yousif1NafieA. Almuslet2ElfatihA. Hassan3FatimaMedany Mohamed Taha4MohammedIdriss Ahmed Mohammed3AbeerEltaybe Fagir Osman5Sudan University of Science and Technology, Khartoum, SudanCollege of Education, Qassim University, Osman, KSAAlmogran College of Science and Technology, Khartoum, SudanCollege of Science, University of Khartoum, Khartoum, SudanCollege of Science in Alkhurma, Taif University, Alkhurma, Saudi Arabia1703202113039110215, February 202126, March 2021 29, March 2021© Copyright 2014 by authors and Scientific Research Publishing Inc. 2014This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/

In this work, Laser Induced Breakdown Spectroscopy (LIBS) was used to determine the constituent of Gum Arabic ( Acacia nilotica ) collected from five different locations in Sudan. Gum samples were irradiated with 80 mJ pulse energy of Nd-YAG laser (1064 nm) and Atomic spectra Database was used for the spectral analysis of the plasma emitted from these samples. It was found that the samples contain the elements C, O, H, S, N, P, Na, Mg, Ca, Fe, Cr, Mn, Co with different amounts. Some elements like (Ti, Br, Ar, Th, Kr, Sc and Pr) are recorded here for the first time.

Gum Arabic LIBS Laser Spectroscopy Gum Investigation1. INTRODUCTION

Laser-induced breakdown spectroscopy (LIBS) is a method of atomic emission spectroscopy (AES) that uses laser-generated plasma as the hot vaporization, atomization, and excitation source [1-4]. Foremost of these is the ability to interrogate samples in situ and remotely without any preparation. In its basic form, a LIBS measurement is carried out by forming laser plasma on or in the sample and then collecting and spectrally analyzing the plasma light. Qualitative and quantitative analyses are carried out by monitoring emission lines positions and intensities [5-7]. LIBS can be used to investigate different materials especially those composed of large molecules such as Gum Arabic. Acacia nilotica Sunt has been found the most valuable timber-producing species [8-10]. An ability to regenerate successfully on flooded sites along the Nile and its tributaries, coupled with timber properties that satisfy most of the utilization standards make the species the most important in the economy of the Sudan. This work aimed to use LIBS for Identification of Gum Arabic (Acacia nilotica).

2. METHODS AND MATERIAL2.1. Experimental Setup

Figure 1 illustrates the LIBS setup which was used in this work. The LIBS system composed of Q-switched Nd-YAG Laser (Laser wavelength is 1064 nm, pulse duration 10 ns, Pulse Energy 80 mj, Spot size 2-8 mm, and repetition rate 2 Hz), Ocean Optics 4000+ spectrometer, connected with PC.

2.2. The Materials

Four samples of GumArabic (Acacia nilotica) (sunt) obtained from different locations in Sudan. Were used in this work, they are illustrated in Table 1.

2.3. Experimental Procedure

Each sample was put in a quartz cell and irradiated by the Nd-YAG laser where the spark of the sample plasma was collected by a fiber optic to the spectrometer which was interfaces to a computer. The emission spectra were collected in the range from 200-900 nm. In order to test the homogeneity of Gum Arabic samples, several LIBS measurements were performed at its surface. The recorded spectra of the samples were analyzed using Atomic Spectral Database (NIST) data.

Irradiation with pulse energy of 80 mJ resulted in generating exited elemental species and cations in higher oxidation states. This was evident from the emission spectral lines corresponding to species such as Cr3+, Ti2+ and Ar3+.

Although the samples of GA in this study were collected from different locations in Sudan having different soil characteristics, their LIBS emission spectra reflect presence of the same elements in all samples. This may indicate that there is no influence of the soil type on the elemental composition of exudates gums like GA.

3. RESULTS AND DISCUSSION

LIBS emission spectra of Acacia nilotica (sunt)gum samples irradiated with laser of 80 mJ pulse energy are shown in Figures 2-5 while Table 2 shows the results of analysis and elemental composition of the mentioned gum samples, which were obtained with the help of Atomic spectra database and the Handbook of basic Atomic spectroscopy.

The elements constituting the samples observed in the emission spectra were C, O, H, S, N, P, Na, Mg, Ca, Fe, Cr, Mn, Co. This is in agreement with findings of other researches published previously. [11-13]. In addition to these, other elements had been detected for the first time in natural gums, namely

Samples grouping
ClassificationLocation of samples collection
Sample (1)South Kordofan
Sample (2)Blue Nile state
Sample (3)White Nile state
Sample (4)Khartoum state

(Ti, Br, Ar, Th, Kr, Sc and Pr).

Interestingly the elements Th, Pr, Kr, and Sc have not been observed in any of the previous studies undertaken on Acacia nilotica using the conventional (AAS or ICP) techniques. These elements and their ions are reported here for the first time in the elemental analysis of Acacia nilotica using LIBS, this adds to the many advantages of this technique, compared to other conventional techniques mentioned above. Sample of Acacia nilotica showed the presence of heavy metals like Fe, Cr, Pr and Th which may hinder its application in food and pharmaceutical formulation.

The analyzed data of Acacia nilotica (sunt) collected from different locations after irradiation by laser energy of 80 mJ
Elementλ(nm)Emission intensity (a.u)
(S11)(S12)(S13)(S14)
Fe I217.0590121.0267110.7591
228.7649106.2807159.9672
314.4824137.4112135.4997
345.0688128.9459133.2605
401.3327119.3883135.4997
498.3784115.2375137.4112112.7252151.8842
516.5037125.1774104.2053127.4713
Fe II185.7174111.0868108.7930
215.7110104.9699121.0267110.7591
258.5961110.7591141.6166
510.0844125.1774112.9437
633.5628116.8760121.3544110.7591
684.1625103.0038149.6450
797.4455149.6450125.5051158.0010
Fe III364.3269118.7329114.9098135.4997110.7591
512.7276125.1774127.4713
538.7827129.0005116.8760
596.5570114.5821
618.4584129.0005
731.7414123.3205122.6990110.7591
823.1230165.4833112.9437
Na I249.1559131.2943114.9098
261.2394103.0038110.7591165.4287
355.2643126.8159137.4112
589.4944104.6422119.0606
691.7147148.0611104.3691104.3145141.9442
Na II242.7364131.2943
254.8200135.4997116.8760152.2119149.6450
308.0630104.6422122.9929
316.3705126.8159158.2195135.4997
519.1470104.2053127.4713
Na III203.0875106.6084104.9699141.6166139.0497
323.9227137.7389125.1774113.2168
395.6685125.1774118.7329135.1720
590.8929114.9098119.0606
652.4433129.3282127.1436113.5991
713.6161162.2610138.0666
Ca I272.1901103.0038108.7930122.9929
616.9480143.8558129.0005127.7990
720.0355163.7902111.0868
734.7623119.7160123.3205112.9437119.0606
Ca II423.2341119.0606103.0038108.7930119.0606
608.6406126.8159119.0606
757.0413164.1179115.2375
Ca III199.3114129.9836114.9098
281.6303120.8083136.7558139.3773
508.1963137.4112112.9437
535.0066129.0005116.8760133.2605
Mg I265.7707120.8083114.9098118.8421
548.6006192.7362121.0267
631.6748116.8760121.3544110.7591
748.7338135.4997113.2714
781.2083114.9098111.0868
805.3753141.2889153.8503129.3282112.9437
847.2900129.3282125.1774125.1774
Mg II355.2643126.8159108.5745
427.0102103.0038108.7930
545.2021141.6166192.7362121.0267
787.6277111.0868112.9437
811.4171137.0835153.8503126.7613
Mg III183.0741111.0868165.4287135.4997
425.1221119.0606103.0038108.7930119.0606
562.5721133.2605139.0479112.9437125.5051
692.4700148.0611104.3691141.9442
704.5535143.5281123.3205133.2605
K I297.1123137.7389165.7564116.8760113.2168
690.9595141.9442104.3691104.3145106.3353
710.9729162.2610114.9098106.9361138.0666
785.7396137.7389112.9437
K II368.8582125.1774121.0267141.6166
380.9418115.2375118.8421
579.1870103.0038108.7930112.6160
K III334.1181111.0868
348.0897133.2605116.5483
388.4940139.0497
457.5966120.8083112.7252112.6160
767.2367104.6422106.9361114.5821145.7673
S I540.2932119.0606192.7362121.0267
558.0408125.1774125.8328125.5051
595.8018114.5821119.0606
673.9671123.3205112.9437112.9437
724.1892110.8137163.7902111.0868
792.9142126.7613108.7930
866.5482108.7930139.3773127.1436
S II361.6836110.7591
405.8640119.3883135.4997
500.6441106.9361164.1179
522.9231131.2943109.1206188.2577135.4997
536.8947114.9098129.0005116.8760
687.9386141.9442155.8164119.0606
740.4264112.9437137.4112
S III252.1768135.4997116.8760114.9098
337.5166161.9333104.9699
632.4300143.5281106.2807110.7591
C I473.4562103.0038133.2605165.4287147.7334
529.3425114.9098116.5483
568.9915139.3773112.6160129.3282121.0267
579.9422112.6160103.0038
763.4606136.1551110.8137163.7902111.0868
C II359.0404125.1774112.9437
625.2554110.7591129.0005106.6084133.2605
663.7716122.9929119.0606
803.1097141.2889153.8503129.3282
C III218.1919131.2943109.1206151.6056135.4997
794.8023149.6450108.7930
853.709114.9098116.8760104.6422
880.5197137.7389139.3773112.9437
N I493.4695110.7591103.0038106.6084135.4997
672.0790106.6084117.2037112.9437
765.3487104.6422114.5821
789.8933111.0868112.9437
870.3243108.7930121.0267
N II384.7179120.8083118.8421
502.5322106.9361176.0240164.1179
531.9857114.9098116.5483116.8760133.2605
593.1585126.8159119.0606119.0606
683.4073103.0038149.6450
700.0222151.8842155.8164119.0606
N III184.5846111.0868104.9699108.7930104.9699
471.1905103.0038136.8651145.7673
489.6934171.8732
644.5135110.7591129.0005106.6084133.2605
O I613.9271143.8558127.1436141.6166106.6084
777.4322122.6990110.7591
840.8707121.0267108.7930141.6166
O II296.469116.8760
394.9133125.1774118.7329135.1720110.7591
444.7578145.7673110.7591
638.094111.4145106.2807
736.6503119.7160103.0038106.9361122.6652
762.7054104.6422114.5821
O III319.3913105.2976158.2195135.4997
351.4882128.9459116.5483
394.5257125.1774118.7329135.1720
650.9329129.3282127.1436113.5991
673.5895123.3205117.2037112.9437
729.4757119.3883110.8137112.9437
749.8667135.4997149.6450113.2714
809. 5290137.0835125.5051158.0010
817.0812161.9333110.4314110.7591127.1436
Cr I194.0248114.9098135.4997
212.1501106.6084104.9699
234.4291114.9098120.6990153.8503147.7334
346.9569133.2605116.5483
456.3637119.3883112.7252104.6422
Cr II253.6872135.4997116.8760152.2119149.6450
275.9662104.6422165.4287147.7334
386.6059120.8083139.0497
554.2647119.0606125.1774120.6990108.7930
572.7676111.0868
Cr V637.7165123.3205106.2807
731.3638119.3883123.3205112.9437149.6450
Ti I259.3513110.7591
370.7463104.6422121.0267114.9098156.0349
478.3651133.2605104.6422
562.1945139.3773139.0479112.9437125.5051
Ti II229.1426114.9098106.2807159.9672
299.0004103.0038136.7558139.3773
430.7863103.1130163.7902111.0868
521.0350131.2943188.2577135.4997
Ti III350.7330133.2605116.5483
755.1532143.5281111.0868119.0606104.6422
829.9200112.9437114.9098110.7591119.0606
Br I238.582119.0606103.0038103.0038147.4047
518.769104.2053127.4713
668.302122.9929125.1774106.3353
813.305161.9333110.4314126.7613127.1436
Br II417.9475103.0038106.9361122.6652
797.8231149.6450108.7930
Ar I375.2776121.0267156.0349
437.9609104.9699135.4997
526.6992109.1206151.6056
556.1528125.1774125.8328108.7930
565.2154139.3773110.7591112.9437
654.7090129.3282127.1436127.7990113.5991
Ar II380.9418120.8083118.8421104.6422
523.6783131.2943109.1206151.6056135.4997
538.4051129.0005135.4997106.6084
684.5402143.5281149.6450103.3315
783.8516114.9098131.2943
879.0093121.0267112.9437
Ar IV244.6246111.0868131.2943104.9699
464.7712103.1130176.0240110.7591
803.4873141.2889153.8503129.3282
Th I373.0119120.8083118.8421156.0349
585.6069104.6422104.6422147.7334
721.1683103.1130163.7902111.0868
764.2159104.6422114.5821145.7673
778.5650108.7930111.0868122.6990110.7591
Th II376.7880121.0267
478.3651133.2605104.6422
537.2723129.0005116.8760
594.6690114.5821119.0606
621.1017110.7591106.6084133.2605
858.6183114.9098104.6422
Kr III213.6605106.6084104.9699110.7591
251.0493135.4997116.8760152.2119114.9098
285.0288136.7558139.3773
371.1239105.2976114.9098156.0349
452.3100112.7252104.6422
Mn II255.4424135.4997116.8760152.2119149.6450
313.7272137.4112
320.5242137.7389105.2976125.1774135.4997
635.4509116.8760121.3544106.2807110.7591
Sc I460.9951112.7252110.7591
474.5890103.0038133.2605104.6422145.7673
544.0693141.6166192.7362
632.0524116.8760121.3544110.7591
Pr II513.4828125.1774127.4713
550.8662192.7362121.0267
587.8720104.6422
594.6690129.3282114.5821119.0606
Co III667.5477122.9929125.1774106.3353
743.8249112.9437111.0868163.7902104.6422
794.4247149.6450111.0868108.7930
P I274.8334104.6422
342.4255128.9459104.6968
474.9666103.0038133.2605104.6422145.7673
551.6215136.1551125.1774120.6990108.7930
H I373.7672121.0267114.9098156.0349
393.0253118.7329
410.395119.3883113.5991111.0868
434.184103.1130135.4997117.2037
486.0502103.0038133.2605171.8732
656.5970202.2938202.6215131.6220110.7591
832.5633110.7591135.4997
4. CONCLUSIONS

Sample of Acacia nilotica showed the presence of heavy metals like Fe, Cr, Pr and Th which may hinder its application in food and pharmaceutical formulation and the elemental composition of Gum Arabic by LIBS technique enabled observing elements, such as Br, Ti and Ar, to be reported for the first time.

CONFLICTS OF INTEREST

The authors declare no conflicts of interest regarding the publication of this paper.

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