144

compounds can only be tolerated up to a certain amount (see Table 2).

Procedure. Place several grains of Dowex HCR resin (H-form) on a white Feigl plate and add I drop of sample solution. Stir the mixture occasionally for at least 5 rain and then add I drop of iron(III) chloride solution (1% in 0.01 M HC1). If hydroxamic acids are present, a brown-violet colour will appear on the grains either immediately or after several minutes.

References

1. Grdini6 V (1981) Fresenius Z Anal Chem 307:205 2. Grdini6 V, Horvat E, Stefanini-Oregi6 L (1981) Fresenius Z

Anal Chem 307:284 3. Qureshi SZ, Bansal R (1981) Fresenius Z Anal Chem 308:32 4. Grdini~ V, Luterotti S (1981) Fresenius Z Anal Chem 308:461

Received September 11, 1981; revised April 20, 1982

Fresenius Z Anal Chem (1982) 313:144 - �9 Springer-Verlag 1982

Borontrifluoride Etherate as a Spray Reagent for the Detection of Steroids and Triterpenoids by TLC

Parthasarathi Ghosh and Swapnadip Thakur*

Department of Chemistry, University of Burdwan, Burdwan 713104, India

Bortrifluoridetherat als Spriihreagens fiir den diinnsehicht-chromatographischen Nachweis von Steroiden und Triterpenoiden

A number of spray reagents for selective and non-selective detection of both steroids and triterpenoids on thin-layer plates has already been described in literature.

In the present paper we present another Lewis acid, borontrifluoride-etherate (BDH, England) for the detection of steroids and triterpenoids on silicagel-G thin layer plate using benzene :ethylacetate (1 : 1) as developing solvent. After develop- ment the plates (0.1 mm) are sprayed with the reagent and heated for 5 min at 125 ~ C. The observed colours and limits of detection are presented in Table 1.

The striking feature of this reagent is the formation of a wide range of colouration for the diverse molecular structures repre- sented by the investigated steroids and triterpenoids. Though the colouration produced by a particular type of skeleton does not bear any distinctive feature, still the formation of an orange and cherry-red colour for the compounds 17 to 21 and 27, 28 having a delocalised electronic environment in ring A indicates the pos- sible chemistry of the colour reaction of this reagent to be of the charge-transfer type.

Tablel. Colour reactions of steroids and triterpenoids with borontrifluoride etherate on silicagel-G thin-layer plates (heating for 5min at 125~

Compound Colour Limit of detection Og)

A. Steroids

1. fl-Sitosterol Pinkish-violet 0.4 2. fi-Sitosterol acetate Pinkish-violet 0.4 3. Stigmasterol Pinkish-violet 0.4 4. Stigmasterol acetate Pinkish-violet 0.4 5. c~-Spinasterol Brown 0.4 6. Cholesterol Pinkish-violet 0.4 7. Cholesterol acetate Pinkish-violet 0.4 8. Cholesterol palmitate Pinkish-violet 0.4 9. Ergosterol Grey 0.8

10. Progesterone Yellow 80 11. 11c~-Hydroxyprogesterone Light-yellow 80

Table 1 (continued)

Compound Colour Limit of detection (gg)

12. 17e-Hydroxyprogesterone Light-yellow 80 13. Pregnenolone Pinkish-violet 0.4 14. Testosterone Pink 70 15. Cortisone Brown 70 16. Hydrocortisone Brown 70 17. Estrone Orange 3 18. Estrone 3-methyl ether Orange 0.8 19. Estradiol Orange 0.4 20. 17e-Ethinyl estradiol Cherry-red 0.8 21. 17c~-Ethinyl estradiol Cherry-red 0.8

3-methyl ether 22. Cis-androsterone Violet 2 23. Dehydro-epi-androsterone Violet 1 24. Androsta-4-ene-17/3-ol-3-one Grey 3 25. 5e-Androsta-17fl-ol-3-one Grey 1 26. 5e-Androsta-3/3-ol-17-one Violet 3 27. Androsta-l,4-dien-3,17-dione Light-orange 2 28. 17-Ketal of androsta-l,4- Light-orange 5

dien-3,17-dione 29. Norethisterone Violet 1 30. Androsta-4-ene-3,17-dione Violet 3

B. Trit-Terpenoids

1. Lupeol Brownish-pink 0.2 2. Methyl betulate Brownish-pink 0.2 3. /~-Amyrin Brownish-pink 0.2 4. /3-Amyrin acetate Brownish-pink 0.2 5. Taraxerol Brownish-pink 0.2 6. Taraxerone Brownish-pink 0.2 7. Taraxerol acetate Brownish-pink 0.2 8. Multiflorinyl acetate Brownish-pink 0.2 9. Methyl oleanolate Brownish-pink 0.2

10. Taraxasterol Brownish-pink 0.2 11. Taraxasteryl acetate Brownish-pink 0.2 12. Glutinol Brownish-pink 0.2 13. Bauernyl acetate Pink 1 14. Methyl crategolate Light-violet 1 15. Methyl ursolate Light-brown 1 16. Friedelin Violet 8

Acknowledgements. We are very thankful to Prof. P. Sengupta and Dr. A. Bhattacharya, Kalyani University, West Bengal for authentic samples of a few phytosterols and triterpenoids, and to Dr. P. Kole, C.D.R.I., Lucknow, for few synthetic steroids. One of us P.G. is grateful to the University of Burdwan for a Junior Research Fellowship.

Offprint requests to." S. Thakur Received February 23, 1982