Biological samples, extraction homogenized

In the case of water or liquid biological samples, extraction is the next step after filtration, while in case of solid samples it comes after homogenization. Many different devices have been used for extraction procedures. The most important techniques in this field are the classical methods of extraction, liquid-liquid extraction, solid phase extraction and liquid chromatographic techniques. The extraction of solid and liquid samples of environmental and biological origin is described separately. 

Biological Samples. There were three types of biological samples obtained from workers at the plant urine, whole blood, and feces. All urine and blood samples were internally "spiked" at the factory with 1 yg/mL of a nitrosopiperidine (NPiP) standard. NPiP was used for spiking because it has a similar stability and recovery characteristic to nitrosomorpholine, and to provide a means of gauging the accuracy of the analytical methods. Due to the inability to perform homogeneous mixing on-site, the feces samples were not spiked until they were thawed upon return to the laboratory. Ethyl acetate extracts of urine samples were examined for the presence of N-nitrosodiethanolamine (NDEIA), a metabolite of NMOR, by HPLC-TEA. All samples were immediately frozen at the plant (-80°C) and kept at this temperature until analysis. 

The biological sample in consideration for analysis is first pulverized then, it is homogenized, sonicated, or disrupted to form a mixture containing cells and subcellular components in a buffer system. Proteins are extracted from this mixture using these substances... 

Prior to total RNA extraction, sample lysis procedures have to be performed. Lysis conditions are very important for the success of the RNA extraction and depend strongly upon the sample used. Due to great diversity, the biological sample can be pulverized, homogenized, sonicated, or otherwise disrupted to yield a mixture that contains cells, subcellular components, and other biological debris in an aqueous buffer or suspension. Here is described the protocol for the Trizol method of RNA extraction. 

SERS may be employed to analyze highly complex biomedical samples. Extracts obtained by homogenizing human lenses, for instance, have been investigated by SERS to. selectively probe for certain biological components, such as adenine containing molecules (5 Amp), aromatic acids (tyrosine and tryptophan) (Sokolov et al., 1991), or lens pigments (Nie et al., 1990). 

For extraction from solid samples, e.g., biological materials and homogenates (planf tissue, food), liquid extraction can be applied using for instance acetone, methanol, or acetonitrile. Often, extracts are filtered prior to injection to LC-MS. 

Biological samples. PCBs can be extracted from biological samples by using acetonitrile or cyclohexane/acetone in an ultrasonic homogenizer and pentane/ dichloromethane or hexane in a Soxhlet apparatus (23, 44-47). 

PCBs can be extracted from biological samples with a Soxhlet or by performing homogenization in the presence of the organic solvent. After the extraction, the sample is homogenized with anhydrous sodium sulphate. Dichloromethane is the most commonly used solvent, " " " " " ... 

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