生物化学技术

Salbutamol sulfate, shown above, is a bronchodilator used for the treatment of asthma. Most of the papers published in relation to salbutamol sulfate analysis described its determination and quantification in tissues and biological fluids of animals under treatment with this drug. No ...

Supercritical fluid chromatography (SFC), particularly with packed columns, has recently being gaining in popularity and is being investigated with increasing frequency for the characterization of pharmaceutical and biological agents. SFC can be described, roughly, as a form of ...

The liver oils of certain shark species contains squalene, 2, 6, 20, 15, 19, 23-hexamethyltetracosahexane, at high levels. Squalene is used in the pharmaceutical, rubber, and surfactants industries (1). Squalene is easily hydrogenated to give squalane, which is an important raw material in the ...

Supercritical fluids and, in particular, supercritical carbon dioxide (SCCO2) are a promising alternative to the use of organic media in enzymatic catalysis (see Chapter 24 and Chapter 25). Among the advantages associated with SCCO2 are its nontoxicity, nonflammability, and relati ...

Enzymatic catalysis in nonaqueous media (see Chapters 23 and 24) has revealed some beneficial features of enzymes such as enhanced thermostability and altered specificity, and thermodynamic equilibria are shifted to favor synthesis over hydrolysis, e.g., esterification and pep ...

The characteristics that make supercritical fluids attractive solvents for extraction also make them potentially interesting solvents for biocatalysis (1) (see Chapters 23 and 25). Of these, the possibility to integrate the steps of reaction and downstream separation is certain ...

Recently, supercritical fluids (SFs) have been used in applications closely related to biotechnology. For example, they have been proposed as media for processing biocompatible polymers to develop new products for medical and pharmaceutical applications (1). It was shown that SFs are ...

Rapid release of the applied pressure on a supercritical fluid solution allows the fluid to expand, its solvent strength to drop, and solute nucleation to occur, forming fine, airborne particles. This phenomenon was first observed more than 100 years ago by the scientists J. B. Hannay and J. Hogarth ( ...

Particle size is a key factor for the performance in the use of different organic and inorganic materials. The first observation on the possibility of obtaining ultrafine powders through supercritical fluid (SF) processing was made in 1876 (1), but not until 1984 did Krukonis (2) demonstrate t ...

Wood contains a variety of materials with potential commercial value, including resins, sugars, extractives, and other compounds that represent raw materials for syntheses. Economic recovery of many of these materials poses a challenge. Many compounds can be recovered using steam or o ...

Wood is a unique combination of the biological polymers cellulose, lignin, and hemicellulose. In living trees, wood serves a structural function supporting the foliage in its never-ending struggle to collect sunlight for photosynthesis. The properties of wood that make it so useful to the l ...

Caffeine—1,3,7-trimethylxanthine—is one of three common alkaloids found in coffee, cola nuts, tea, cacao beans, mate, and other plants. The other two are theophylline and theobromine (1). The effects of caffeine are commonly reported to be as a stimulant of the central nervous system, cardiac m ...

Although several methods can be used to dry specimens for examination with the scanning electron microscope (SEM), critical point drying (CPD) is by far the most widely used. The technique was first introduced by Anderson (1) to preserve three-dimensional structure of biological specime ...

Latent fingerprints on paper and other porous surfaces can be developed using chemical methods so that they become visible to the naked eye and available as forensic evidence (1,2). Ninhydrin is the most commonly used reagent for developing fingerprints as it reacts with amino acids present in ...

Supercritical fluid extraction or SFE (see Chapter 1) is used to isolate pesticides from environmental samples, fruits and vegetables. However, the use of this technique for the extraction of residues, such as nitrosamines at the ppb level, in cured meat products is relatively recent.

Polychlorinated biphenyls (PCBs) are of great concern to the scientific and regulatory communities due to their tendency to accumulate to toxic levels in the edible tissues of fish and other organisms (1–4). PCBs are nonpolar compounds that can partition into the lipid reservoirs of edible t ...

Melengestrol acetate (MGA)—17α-hydroxy-6-methyl-16-methylene-pregna-4, 6-diene-3,20-dione acetate (Fig. 1)-is a synthetic oral progestational steroidal hormone that is added to the feed of heifers to suppress estrus (heat), thereby leading to improved feed efficiency and r ...

Polynuclear or polycyclic aromatic hydrocarbons (PAHs) are mutagenic compounds formed by incomplete burning of organic material. The mutagenity and carcinogenic activity becomes higher as the number of fused rings in a molecule increases (1). The human intake of PAHs is very variable. ...

Eschscholtzia californica Cham. or the California poppy is the state flower of California. The chemical constituents of the epigeous parts of this plant have been extensively investigated for their isoquinoline alkaloid components (1,2). The hydroalcoholic tincture of the bloom ...

Trichothecenes are sesquiterpenoid mycotoxins produced by a variety of species of imperfect fungi. These mycotoxins are found mainly as products of field flora in grains and cereals. Trichothecenes show a wide range of toxicity, which is dependent on the structure of the molecule. Over 150 t ...