สารบัญ

Thai name  น้ำมันผิวส้มหวาน (NAMMAN PHIU SOM WAN)

Category Pharmaceutic aid.

             Sweet Orange Oil is the volatile oil without heating, by suitable mechanical treatment from the fresh peel of the fruit of Citrus × sinensis (L.) Osbeck (Family Rutaceae).  It contains not less than 1.0 per cent w/w of aldehydes, calculated as decanal, C₁₀H₂₀O.

Origin of plant; Constituents  See under Orange Oil.

Description  Clear, pale yellow or orange, mobile liquid, which may become cloudy when chilled.

Packaging and storage  Sweet Orange Oil shall be kept in well-filled, tightly closed containers, protected from light, and stored at a temperature not exceeding 25°.

Identification  Carry out the test as described in the “Thin-Layer Chromatography” (Appendix 3.1).
     Standard solution  Dissolve 2 mg of bergapten, 10 µL of linalool, and 20 µL of linalyl acetate in 10 mL of ethanol.
     Test solution  Dilute 0.2 mL of the sample in 1 mL of ethanol.
     Adsorbent  Silica gel G.
     Mobile phase  Ethyl acetate and toluene (15:85).
     Application  Apply 10 µL each of Standard solution and Test solution as 10-mm bands.
     Development and drying  Dry the developed plate in air.
     Detection A  Examine the plate under ultraviolet light (366 nm).
     Results A   When examined under ultraviolet light (366 nm), the test solution shows many blue fluorescent bands in the lower third of the chromatogram.  No greenish yellow fluorescent band corresponding to the bergapten band obtained from the standard solution appears. A greenish yellow fluorescent band corresponding to the bergapten band obtained from the standard solution appears also in the middle of the chromatogram.
     Detection B  Spray the plate with anisaldehyde TS, heat at 105° for 10 minutes, and examine under ultraviolet light (366 nm).  Observe the result.
     Results B  When examined under ultraviolet light (366 nm), the test solution shows a brownish orange fluorescent band due to linalool in the middle of the chromatogram and a faint brownish orange fluorescent band due to linalyl acetate in the upper third of the chromatogram, corresponding in colour and R_f to the bands shown by the standard solution.  Many blue fluorescent bands in the lower third of the chromatogram, many brownish orange fluorescent bands and many orange fluorescent bands in the middle of the chromatogram, and a brown fluorescent band in the upper third of the chromatogram are present.  No faint greenish yellow fluorescent band corresponding to the bergapten band obtained from the standard solution appears. 

Test for Bergapten  Carry out the test as described in the “Thin-Layer Chromatography” (Appendix 3.1).
     Standard solution  Dissolve 2 mg of bergapten, 10 µL of linalool and 20 µL of linalyl acetate in 10 mL of ethanol.
     Test solution  Dilute 0.2 mL of the sample in 1 mL of ethanol.
     Adsorbent  Silica gel G.
     Mobile phase  Ethyl acetate and toluene (15:85).
     Application  Apply 10 µL each of Standard solution and Test solution as 10-mm bands.
     Development and drying  Dry the developed plate in air.
     Detection A  Examine the plate under ultraviolet light (366 nm).
     Results A  When examined under ultraviolet light (366 nm), the test solution shows no greenish-yellow fluorescent band corresponding to the bergapten band obtained from the standard solution. 
     Detection B  Spray the plate with anisaldehyde TS, heat at 105° for 10 minutes and examine under ultraviolet light (366 nm).  Observe the result.
     Results B  When examined under ultraviolet light (366 nm), the test solution shows no faint greenish yellow fluorescent band corresponding to the bergapten band obtained from the standard solution.

Relative density  0.842 to 0.850 g (Appendix 4.9).

Refractive index  1.470 to 1.476, at 20º (Appendix 4.7).

Optical rotation  +94° to +99° (Appendix 4.8).

Peroxide Value  Not more than 20 (Appendix 5.12).

Residue on evaporation  1.0 to 5.0 per cent w/w when determined by the method for “Residue on Evaporation of Volatile Oils” (Appendix 7.13).  Use 5 g and heat for
4 hours.

Assay  Carry out the method for the “Determination of Aldehydes” (Appendix 7.9), using 10 g, omitting the toluene and using a volume, not less than 7 mL, of hydroxylamine in ethanol (60 per cent) TS that exceeds by
1 to 2 mL the volume of 0.5 M potassium hydroxide in ethanol (60 per cent) VS required.  Each mL of 0.5 M potassium hydroxide in ethanol (60 per cent) VS is equivalent to 78.76 mg of C₁₀H₂₀O.