do not receive Channel 6—the Essex House, Holiday Inn (57th St.), and Park-Sheraton. TV monitor sets will be set up in public areas in the Americana, New York Hilton, Statler Hilton, and Waldorf-Astoria. ACS members attending the meeting are urged to watch as many of the special shows as possible and to indicate their opinions on the questionnaires that will be included with registration materials. The Society wants to know if this type of member communication is of sufficient value to warrant its inclusion in future national meetings. The experiment, arranged by the Divisions of Membership Activities and Public, Professional, and Member Relations, is being undertaken in an effort to give members better information on what is going on overall.
chemists place a 2- to 5-microliter sample in the microreactor and flow a stream of ozonized oxygen over it at room temperature. When reaction is complete, they shut off the ozone and switch to helium. They then insert the outlet needle on the reactor into the injection port of the chromatograph and heat the reactor to 250° C. by activating the soldering gun. This decomposes the ozonide and volatilizes the products. The resulting aldehydic fragments are swept into the chromatograph. Dr. Dutton points out that this is the first method to quantitatively de-
Fats' double bonds found fast U.S. Department of Agriculture scientists have found a new and faster way to locate unsaturation in fatty esters and to determine the fatty-acid content of vegetable oils. Key to the technique, developed by Dr. Herbert J. Dutton and Verle L. Davison of USDA's Northern Utilization Research and Development Laboratory, Peoria, 111., is a microreactor made out of a soldering gun. Unsaturation is located by an ozonization method and the fatty-acid content via transesterification. With the technique, microliter samples are reacted (with ozone, for example) in the microreactor and the products injected directly into a gas chromatograph for analysis. A complete analysis can be done in an hour. Current methods involve preparing and separating products and take up to a week. Also, these older methods are less versatile and require larger samples than the new method. The microreactor consists of a copper-encased, V s -inch o.d. stainless steel U-tube. It fits between the poles of a soldering gun, replacing the gun's tip. A hypodermic needle is fixed to one end of the tube. On the other end is a gas connection and a septum through which sample can be introduced. To locate unsaturation, the USDA chemists ozonize the fatty ester, thermally decompose the ozonide, and analyze the resulting fragments [Anal. Chem., 38, 1302 ( 1 9 6 6 ) ] . Ozonized fatty esters, rupturing at the site of unsaturation in the original ester, yield an aldehyde fragment and an aldehydic ester fragment. Hence, unsaturation in the original ester can be located by analyzing these fragments. With the new technique, the USDA
Microreactor Made from soldering gun
termine the position of unsaturation in complex mixtures. Earlier methods are limited to qualitative determination on single compounds, he says. For the transesterification used in measuring the fatty-acid content of triglyceride vegetable oils, the USDA workers introduce 2 microliters of oil and 3 microliters of 2.7M sodium methoxide (in methanol) into the microreactor. They then heat the reactor to 50° C. for 20 to 30 seconds and immediately add formic acid. After removing excess reagents from the resulting methyl esters (by heating the reactor to 100° C ) , they raise the temperature to 250° C. and sweep the esters into the chromatograph in a stream of helium. Dr. Dutton says that the method gives good agreement when tested against oils of known fatty-acid content and against older, macro methods. In a series of tests, standard deviation was 1.26% for the new method and 1.249c for the macro method. Relative variation for individual components was 9.58% with the new method, 11.09% with the old.
Layer lyophilization patented A patent on a process that can overcome the problem of limited shelf life of some pharmaceuticals, including injectable vitamin mixtures and vaccines, was issued last week. The patent, U.S. 3,269,905, covers layer lyophilization, a freeze-drying process that produces a layered solid product with each ingredient in a separate layer. Such solid systems, which are reconstituted with a diluent before use, have an improved shelf life. Interaction between the ingredients—the usual cause of instability—is eliminated. The patent is assigned to Alpar Laboratories, Inc., La Grange, 111. Inventor is Charles W. Damaskus, head of Alpar. The company uses the process to make a line of mixed vitamins. Mr. Damaskus has had to wait a long time for his patent. He did his first work on the process in the early 1950's when he worked for Armour Pharmaceutical. Armour filed a patent application in 1955. But protracted interference involving Armour, The Upjohn Co., and Farbenfabriken Bayer, A.G., started soon after. In 1961 Armour stepped out of the picture, assigning its rights to Mr. Damaskus who was finally declared inventor of the process by the Patent Office in 1963. Subsequent amendments to the original application delayed issuance of the patent. The patent does not restrict layer lyophilization to drug use. The method may also find food applications, for instance. But Mr. Damaskus sees the process as being particularly appropriate for making injectable vitamin mixtures. Most of these mixtures are sold in solution form and have a shelf life of six months to two years. According to Mr. Damaskus, such systems prepared more than 10 years ago by layer lyophilization still have their full potency. Pie adds that the process has potential applications in making mixed vaccines. An example of the use of the new process for vitamins is in packaging vials of a mixture of folic acid, parenteral liver concentrate, and vitamin B 32 . Each of these components is made up in a separate aqueous gelatin solution. (Gelatin is a bulking agent and speeds reconstitution.) A layer of the folic-acid solution is first run into the vial and frozen. Liver concentrate solution is then run in on top of the frozen folic-acid layer and the vial frozen again. Vitamin B 1 2 solution is then added and frozen the same way. The complete frozen system is then freeze dried; it forms a plug consisting of separate layers of the solid components. SEPT. 5, 1966 C&EN
21
