Determination of Purity Analysis of Menthol (Raw Material for Ointment) Through Gas Chromatography

 Sanjeet Kumar and Itishree Sen. (2011). Purity Determination of Menthol (Raw Material for Ointment) Through Gas Chromatography Analysis. Emerging Science. 3(1): 22-24.

Determination of Purity Analysis of Menthol (Raw Material for Ointment) Through Gas Chromatography

                        

 Sanjeet Kumar¹ and Itishree Sen²

       2.  Q.C.Chemist, Darex labs Pvt. Ltd. Hyderabad-38

Abstracts / Résumé

La chromatographie en phase gazeuse (CPG) est une méthode séparative parmi les plus employées car elle allie rapidité et efficacité de séparation.  L’objectif de cet article est d’expliquer simplement les principes de la chromatographie en phase gazeuse et l’analyse de pureté de différent copmosés organiques par chromatographie en phase gazeuse, ici nous avons fait l’analyse de pureté de le menthol.

                                                              Summary

The gas chromatography (GC) is a separation method of the most used because it combines speed and separation efficiency. The aim of this paper is to explain simply the principles of gas chromatography and purity analysis of different organic compounds by gas chromatography, here we have analyzed the purity of menthol.

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INTRODUCTION

Russian botanist Tswett is credited with the discovery of Chromatography. In 1903 he succeeded in separating plant pigments using two phases. In 1941 Martin and synage awarded the Nobel Prize for their work which was liquid-liquid partition chromatography. Chromatography is an analytical method of separation of analytes also for identification and determination of chemical components of a analytes.The gas chromatography is based on the separation of analytes between two phases, a stationary phase and a mobile phase, in GC the mobile phase is Gas therefore this chromatographic technique is called Gas Chromatography. It is a specific chromatographic technique that can be used to separate volatile Organic compounds which is at 400-450 degree Celsius or below not decompose the compound can probably be analyzed by GC. A.T.james and Martin used firstly this technique in 1952; they separated the organic acids and amides.

Menthol

Menthol is an organic compound made synthetically or obtained from peppermint or other mint oils. It is a waxy, crystalline substance, clear or white in color, which is solid at room temperature and melts slightly above. Menthol is widely used in a number of products and features certain therapeutic qualities. It was first isolated from peppermint oil in 1771 in the West, but it may have been in use in Japan for much longer

Chemistry of Menthol

Menthol (C10H20O), cyclohexanol-5-methyl-2-(1-

Methylethyl), the major constituent of peppermint oil, is a monocyclic terpene alcohol that naturally occurs in plants of the Mentha species Menthol has three asymmetric carbon atoms in its cyclohexane ring (Figure 1) and therefore occurs as four pairs of optical isomers: (2)- and (z)-menthol, (2)- and (z)-neomenthol, (2)- and (z)-isomenthol, and (2)- and (z)-neoisomenthol (Eccles, 2000).

(2)-Menthol is the isomer that occurs most widely in nature and produces the characteristic peppermint odor and cooling sensation when applied to the skin and mucus membranes (Watson, Hems, Rowsell, & Spring, 1978). The other isomers of menthol have a similar odor but do not have the same cooling actions of (2)-menthol (Eccles, 1994, 2000).

Structure of Menthol

Natural menthol exists as one pure stereoisomer, In the natural compound, the isopropyl group is in the trans orientation to both the methyl and hydroxyl groups. Menthol is the only tobacco additive promoted and advertised by the tobacco industry.

Menthol: - A BOON

Menthol has many potential properties like:-

v  lip balms and cough medicines

v  As an antipruritic to reduce itching

v  As a topical analgesic to relieve minor aches and pains such as muscle cramps, sprains, headaches and similar conditions,

v  In decongestants for chest and sinuses (cream, patch or nose inhaler) Examples: Vicks Vaporub.

v  In certain medications used to treat sunburns, as it provides a cooling sensation (then often associated with Aloe)

Material and Methods:-

The Organic Compounds and Samples are obtained from Darex Labs and all the analysis was done at Darex Labs Pvt. Ltd. Hyderabad -38. The Chromatographic conditions and analysis procedures are according to Indian Pharmacopeia 1996.

Chromatographic condition for Menthol

Split ratio: - 20:01

Inject Temp.:- 220 degree Celsius

Flow rate: - 3 ml/mint

Detector temp: - 240 degree Celsius

Sample volume: - 1µl

Standard volume: - 1µl

Column – BP5

Blank – Isooctane.

Programme for Oven: - Initially temp 60 degree Celsius for 0 minute and raised to 200 degree Celsius at the rate of 10 degree Celsius par minute and hold it 5 minute at 220 degree Celsius.

Preparation of standard:-

0.1gm of standard menthol dissolved in 10 ml volumetric flask and make with isooctane.

Preparation of Sample:-

0.1gm of sample menthol dissolved in 10 ml volumetric flask and make with isooctane.

The Purity % =

(Sample area / standard area × standard weight /standard dilution × sample dilution / sample weight × 99.6 / 100) ×100

Results:-

Using the chromatographic conditions followed Indian pharmacopeia 1996; found the following RT and Purity % of Menthol.

Table 1. Reading for Menthol

	RT(Min)	Area(mV*sec)	Area %
Std 1	6.8683	686494.25	99.23
Sample	6.8017	62951.9125	98.01

Where,

RT –Retention Time, Purity % =

(62951.91 / 686494.25 × 0.1 /10 × 10 / 0.1 × 99.6 /100) × 100

After calculation the purity % = 91.30 %

Conclusion:-

The Gas Chromatography is the powerful analytical tools in analysis of compounds due to its limiting factor, which is volatile and thermal stable, also the diversity of modes of injection and capillary columns allows the purity analysis of chemical compounds and metabolites. The purity % of Menthol shows the potential of GC in purity analysis.

References 

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4.      Eccles (1994). "Menthol and Related Cooling Compounds". J. Pharm. Pharmacol. 46 (8): 618–630. 

5.      Eccles, R. (1994). Menthol and related cooling compounds. Journal of Pharmacy and Pharmacology, 46, 618–630.

6.      Eccles, R. (2000). Role of cold receptors and menthol in thirst, the drive to breathe and arousal. Appetite, 34, 29–35.

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8.      Harris, Daniel C. (1999), "24. Gas Chromatography", Quantitative chemical analysis (Fifth ed.), W. H. Freeman and Company, pp. 675—712.

9.      Indian Pharmacopoeia. Monograph of peppermint oil. 1996.

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12.  Watson, H. R., Hems, R., Rowsell, D. G., & Spring, D. J. (1978). New compounds with the menthol cooling effect. Journal of Cosmetic Chemistry, 29, 185–200.

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