For optical purity analysis and separation of optical Isomers
The
Second Wave of Pirkle Columns from Regis The first wave Based on an approach developed by Dr. William H. Pirkle of the University of Illinois, a first wave of chiral columns was introduced by Regis in 1982. These columns were packed with silica-bonded dinitrobenzoyl (BNB) derivatives of phenylglycine and, later, leucine. Today these columns are finding wide use in separating optical isomers from many classes of aromatic compounds such as alcohols, sulfoxides, bi-βnaphthols, β-hydroxysulfides, and agents related to propranolol.
The second wave Now Regis introduces a second wave: The new Pirkle covalent naphthylalanine HPLC columns. These columns are especially designed for separating the DNB derivatives of amines, amino acids, alcohols, and thiols. These new columns are startlingly selective, with relative retentions as high as 16.5 already reported. These second wave columns are also characterized by typical Regis advantages: They are covalent, highly efficient, based o n spherical silica, and strongly guaranteed. The guarantee: If, for any reason, you are not satisfied with the performance of your Regis column, simply r e t u r n it for a full refund.
How supplied The first w a v e , s t i l l available and w i d e l y used Ionic 25 cm columns D-Phenyl Glycine
L-Leucine Covalent 25 cm columns D-Phenyl Glycine L-Pheriyl Glycine D,L Phenyl Glycine L-I^mctne The beginning of the second wave Covalent 86 cm columns D-NaphUiyl Alanine L-Napcthyl Alanine Regis Pirkle column literature available upon request from your Regis Distributor, or write:
Regis Chemical Co. 8210 Austin Avenue Morton Grove, Illinois 60053 USA
years relative to polyclonal antibodies, but the generation and purification of any of these antibodies still remain a major effort for those who develop im munoassays. In addition, although ra diolabeled tests can be quite sensitive, the use of other methods of detection, such as enzyme-linked or enzyme-am plified detection and fluorescent or lu minescent tags, is receiving increased attention. These nonradiolabeled tags would minimize some of the problems with many of the current radioimmun oassays, such as those associated with safety, stability of reagents, and the need for specific equipment to detect radiolabeled species. Two other aspects of immunoassays are receiving increased attention— automation and reliability. A large number of immunoassays are done in the United States each year, especially in clinical labs. The growth of these analyses will depend on the continu ing ability to automate these methods and obtain a high degree of reliability. Reliability is especially important in the case of disease diagnosis—for ex ample, AIDS test kits—where an in correct analysis could have profound consequences. Finally, although many immunoassays are currently related to medical diagnosis and drug detection, in principle an antibody can be devel oped against any organic molecule of interest. In fact, analysis methods based on immunoassays have recently been described for a specific herbicide residue in soil and PCBs in environ mental samples. These types of tech niques will represent a substantial business in the future. Chromatographic separations The importance of the separations process in biotechnology cannot be overstated for work in research and development through production proc esses. The complexity of both natural sample mixtures and of those using re combinant technology to produce large quantities of a specific biomolecule results in many cases where most of the work involved in a process is separations intensive. The initial work in separations is for analytical purposes—to purify and then identify a biologically useful ma terial for further study. However, once research studies have begun, the sepa rations quickly become preparative. In biotechnology, unlike many chemical processes, the scaleup factors from the laboratory bench to the industrial proc ess can be relatively small. For exam ple, a typical bioactive protein could be purified on a milligram scale using analytical equipment, and total pro duction may be only a kilogram or less per year. Traditionally, biologists and bio chemists have used various forms of
CIRCLE 184 ON READER SERVICE CARD 388 A • ANALYTICAL CHEMISTRY, VOL. 58, NO. 3, MARCH 1986
open-column chromatography involv ing ion exchange, size exclusion, hy drophobic interactions, and affinity for lab purification. More recently, the use of high-performance liquid chro matography (HPLC) has begun to show promise with regard to analysis speed and resolution, but many of the initial workups are still done by tradi tional methods in many laboratories. There are many challenges facing researchers who use separations for analysis and preparative methods. Many separations techniques are bio chemically dependent (such as affinity chromatography), and the develop ment of optimal methods requires a good working knowledge of the bio chemistry involved. A fundamental understanding of the complex mecha nisms involved in many of these sepa rations is still needed to further im prove them. Support materials are needed that are stable, nonadsorptive, selective, and rigid so that these lab separations can be easily scaled to process levels. In general, chromatog raphy can be a powerful technique, but often where to start and what to do first are of prime importance to the overall success of a separations scheme. Finally, specific problems still exist in the fields of very hydrophobic proteins, membrane proteins, highly glycosylated materials, and extremely large protein aggregates and DNAs. Sequencing—protein and DNA One of the most fundamental analy sis needs in biotechnology today is for primary-structure information on the biomolecules of interest. The basic technology for sequencing both pro teins and DNA exists, and its applica tion over the past decade has resulted in an explosion of information on the primary sequence of many biomole cules. Despite this effort, however, only a small fraction of the DNA and proteins in mammals has been se quenced, and there is an enormous amount of work remaining in primarysequence determination. The sequencing of proteins or pep tides is done using Edman chemistry, which was introduced in the early
