Chromatography procedures

The batch and fed-batch procedures are used for most commercial antibiotic fermentations. A typical batch fermentor may hold over 150,000 Hters. When a maximum yield of antibiotic is obtained, the fermentation broth is processed by purification procedures tailored for the specific antibiotic being produced. Nonpolar antibiotics are usually purified by solvent extraction procedures water-soluble compounds are commonly purified by ion-exchange methods. Chromatography procedures can readily provide high quaHty material, but for economic reasons chromatography steps are avoided if possible. 

The successful separation of xanthate-related compounds by high performance Hquid chromatography (hplc) methods has been reported (91—93). The thin-layer chromatography procedure has been used to determine the nature of the alcohols in a xanthate mixture. A short mn of 3 cm at a development time of 25 min gives a complete separation of C —alkanol xanthates (94). 

Adams, R. F., Schmidt, G. J., and Vandemark, F. L., A micro liquid column chromatography procedure for twelve anticonvulsants and some of their metabolites, /. Chromatogr., 145, 275, 1978. 

Liquid Chromatography Procedure for Polyolefin Additives, WAPP-100, Waters, Milford, MA (1978). 

Modified procedure (ASC kit) Ascorbic acid is isolated from plasma proteins and uric acid in a single-step liquid gel chromatography procedure and its amount... 

Spectrophotometric determination with 4-hexylresorcinol and a fluorometric method with m-aminophenol are the most commonly used procedures for the determination of acrolein. However, gas chromatography and high-performance liquid chromatography procedures are also used (USEPA 1980 Kissel etal. 1981 Nishikawa and Hayakawa 1986). Acrolein concentrations in rainwater between 4 and 200 pg/L can be measured rapidly (less than 80 min) without interference from related compounds the method involves acrolein bromination and analysis by gas chromatography with electron capture detection (Nishikawa and Hayakawa 1986). Kissel etal. (1981) emphasize that water samples from potential acrolein treatment systems require the use of water from that system in preparing blanks, controls, and standards and that acrolein measurements should be made at the anticipated use concentrations. 

It is important that all volatile solvents are removed, particularly f-butyl alcohol, since its presence will interfere with the subsequent chromatography procedure. The checkers obtained approximately 9.0 g. of crude material. 

High-performance liquid chromatography (HPLC) grade Solvents of suitable purity for use in liquid chromatography procedures. 

SACHEM Inc., located in Cleburne, Texas, is a producer of high-purity bulk chemicals for companies that have high-purity requirements in their chemical processing. As stated in Workplace Scene 1.2, one of their products is tetramethylammonium hydroxide (TMAH), which is sold to semiconductor industries. The analysis of TMAH for trace anions such as chloride, nitrate, nitrite, and carbonate is critical for SACHEM s quality control laboratory. If these ions are present on the integrated circuit boards manufactured by one of their semiconductor customers, they may cause corrosion severe enough to affect the functionality and performance of the electronic devices in which the circuit boards are used. In SACHEM s quality control laboratory, ion chromatography procedures have been developed to measure the anion concentrations in TMAH. Because the concentration levels are trace levels, a clean room environment, like that described in Workplace Scene 1.2, is used. A special procedure for carbonate analysis is required so that the absorption of carbon dioxide from the atmosphere can be minimized. 

The chromatogram produced by gas chromatography (Procedure 3.2) is comparable to that produced by HPLC and all the considerations regarding peak height and area measurements, and internal and external standards are relevant. The... 

SEC System, Data Processing, and Chromatography Procedures. The SEC/LALLS system contained a Model IlOA pump (Altex), Model 7125 injector (Rheodyne), KMX-6 Low-Angle Laser Light Scattering Photometer (LDC/Milton Roy), and a Model 98.00... 

Even though the number of pesticides surveyed amounted to more than 100, only 46 were actually detected (Table V). From records that were kept as well as unidentified GLC peaks, other pesticides were deposited Into the beds but either were not detected by the gas chromatography procedure, were present In undetectable levels or were unknown or unregistered compounds. Tables VI to XI show the average accumulated pesticide concentrations from each of the six field stations having the heaviest use of the evaporation beds. 

Thin Layer Chromatography Procedures. Silica gel G (Suppelco, Redi-coat, 5 X 20 cm X 0.25 mm) plates were activated by heating in an oven for 1 hour at 110°C. Toxic products were spotted onto duplicate plates at concentrations corresponding to their previously determined LD99 levels. The plates were developed to 14 cm with chloroform, methanol and (6N) ammonium hydroxide (90 9.5 0.5) or chloroform, methanol, and water (60 35 8). Plates were developed and visualized by spraying with 50% aqueous sulfuric acid and charring. Undeveloped plates were scraped, the silica gel fines removed and the extracts concentrated to a residue under a nitrogen gas stream. 

Enzyme-linked immunosorbent assay is a heterogenous immunoassay. Reactions involve a solid phase to which components are sequentially presented and successively bound. This method is very effective in the determination of the total alkaloid content. The positive characteristics of this method are the use of non-toxic reagents and basic equipment with low costs, a small sample volume and the ability to measure alkaloids in crude sample extracts. According to the literature, compared with results obtained from GLC, the precision of ELISA for quinolizidine alkaloids is not as high as that of the gas chromatography procedure, but is adequate for plant breeding purposes. The use of enzymes in developing the methods of quinolizidine alkaloids analysis looks likely to increase in the future. 

Chlorpromazine was analyzed in different body biological fluids by a variety of gas chromatography procedures [188-198], the operating conditions for some of which are given in Table 8. 

Hepatitis B immune globulin (human), purified by chromatography procedure... 

The within-run precision of derivatisation and chromatography procedures was assessed in the reported work a single standard solution was analysed in eight replicates. The relative standard deviation values of the peak-height ratios ranged from... 

Higher-specificity techniques such as immunoaffinity chromatography have been also found widespread acceptance for the determination of chloramphenicol residues in edible animal products. The first pertinent reports concerned the determination of chloramphenicol residues in swine muscle (60) and milk and eggs (21). Alternative immunoaffinity chromatography procedures were suggested later for exiraction/preconcentration of chloramphenicol residues from swine tissues (50), or for online immunoaffinity extraction for the determination of chloramphenicol in milk and swine muscle by an automated column-switching system (22). 

J. R. Troost and E. Y. Olavasen [ Gas Chromatographic/Mass Spectrometric Calibration Bias, Anal. Chem. 1996,68, 708] discovered that a chromatography procedure from the U.S. Environmental Protection Agency had a nonlinear response on a variety of instruments. The assumption of constant response factor led to errors as great as 40%. 

Three recent reviews specifically cover HPLC methods for quantitating riboflavin in foods. In addition to HPLC methods, Nielsen (81) summarized paper chromatography, TLC, and open-column chromatography procedures for quantitating total riboflavin and the individual vitamers in foods, pharmaceuticals, and biological samples. Russell (44) included a brief discussion of the standard methods, along with HPLC and flow injection analyses published between 1990 and 1994 for total riboflavin and the individual vitamers in foods. Ball (45) reviewed HPLC methods for quantitation of riboflavin, as well as chemical and microbiological riboflavin assays for foods. 

Schraer, S.M., D.R. Shaw, M. Boyette, et al. 2000. Comparison of enzyme-linked immunosorbent assay and gas chromatography procedures for the detection of cyanazine and metolachlor in surface water samples. J. Agric. Food Chem. 48 5881-5886. 

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