COPAI′BA. Syn. Copai′va, Copaiva balsam, Capiv′i, Balsam of capiv′i; Copai′ba (Ph. L. E. & D.), L.; Baume de Copahu, Fr.; Cobaiva balsam, Ger. “The oleo-resin, of a brown colour, obtained by incision from the trunk of Copaifera multijuga.” (B. P.) Most of the balsam of commerce is obtained from Para and Maranhao. It is packed in casks containing from 1 to 11⁄2 cwt. each, or in large bottles, or in cylindrical tin boxes.
Prop., Purific., &c. Copaiba, though usually called a ‘balsam,’ is not correctly so named, as it contains no benzoic or cinnamic acid. It is correctly described in the B. P. as an ‘oleo-resin.’ Considerable variation exists in the colour, odour, consistence, and transparency, as well as in the proportion of oil and resin yielded by different samples, scarcely any two of which exactly agree. The sp. gr. varies from ·950 to ·996. Brazilian copaiba is thin, clear, and pale; whilst the West Indian variety is thick, golden yellow, less transparent, and has a less agreeable and somewhat terebinthinate smell. Some varieties are opaque, and continue so unless filtered. This is often a most troublesome operation. The opacity generally arises from the presence of water, which it retains with great tenacity. The following is the plan we have found to answer on the large scale:—Place the casks upon their ends in a warm situation, and leave them so for 10 days or a fortnight, or longer, if convenient. They may then be tapped a little above the bottom, when the contents of some of them will generally be found quite transparent, and may be drawn off and vatted, care being taken to avoid shaking up the bottom. The copaiva that remains foul must be filtered through one or more long Canton flannel bags, sunk in the bottom of a tin cistern, placed over a suitable receiver, in a similar way to that adopted for oils; a few pounds of coarsely powdered charcoal being mixed up with the first 5 or 6 gallons thrown in. This will rapidly fill up the pores of the bag, and make the balsam soon flow clear and pale. The “bottoms” of the casks, containing the water and impurities, may be poured into a large can or jar, and allowed to settle for a few days, when the copaiba may be poured off the top and filtered. A sudden change of temperature will frequently turn a transparent sample of this article opaque or milky; it is not, therefore, deemed fit to send out by the wholesale trade, unless it stands this test. To ascertain this point a common practice is to fill a small bottle with the copaiba, and to leave it out of doors all night in an exposed situation.
Pur., Tests, &c. This substance is frequently adulterated; indeed, fully one half that sold for copaiba does not contain 10% of the genuine balsam. This is particularly the case with that sold in capsules, at low prices, in the shops. Pure balsam of copaiba may be recognised by the following characters:—
1. (Ph. E.) It is transparent; free of turpentine odour when heated; soluble in 2 parts of alcohol; and dissolves one fourth of its weight of carbonate of magnesia with the aid of a gentle heat, and continues translucent.
2. (Chevallier.) A drop of the balsam, placed on a piece of unsized paper, and heated until all the essential oil is expelled, forms a semi-transparent, well-defined spot; but if the balsam has been adulterated with a fatty oil, it is surrounded by an oily areola.
3. (Planche.) 21⁄2 parts of balsam shaken with 1 part of solution of ammonia, sp. gr. ·965, forms a mixture which becomes clear and transparent in a few moments, and may be heated to 212° Fahr. without becoming opaque.
4. (Vigne.) Boiled with 50 times its weight of water for 1 hour, it should lose at least half its weight.
5. (Adder.) By agitating the suspected sample with a lye of caustic soda, and setting the mixture aside to repose, the balsam after a time rises to the surface, and the fatty
oil present (if any) forms a soapy, thick mass below.
6. (‘Journ. de Pharm.,’ 1842.) Pure copaiba may be adulterated with 50 per cent. of a fat oil (nut, almond, or castor oil), without it ceasing to give a clear solution with 2 parts of alcohol; but it combines badly with magnesia and ammonia. Excess of alcohol, however, separates the oil in all cases. It was formerly considered that the best test for detecting the fat oils was pure alcohol, to which some caustic potash had been added.