Folch method

Bligh Dyers Folch Method Grey Method Alex Brown Hexane Extraction... 

In order to prevent the formation of a stable emulsion at any stage of the extraction procedure, the water content of the hydrated WPC has to be controlled so as not to obtain a biphasic solvent system during extraction with mixtures of chloroform and methanol. Besides, nonlipid contaminants are removed from the extract by gel filtration on nonlipophilic Sephadex G-25 instead of traditional aqueous washing total lipids were eluted with a 19/1 (v/v) mixture of chlo-roform/methanol, saturated with water, whereas a 1/1 (v/v) mixture of water and methanol eluted nonlipid contaminants. The method yields a similar total lipid content to the Folch method, but it is about four times faster (24). 

Currently, there is no doubt that the most widely used method for extraction of tissue lipids is that of Bligh and Dyer (1959). Basically, this is a modification of the Folch method and employs a careful calculation of the amount of sample (tissue) water such that the overall mixture will have a final composition of chloroform-methanol-water of 1 2 0.8 (v/v). Thus, a singlephase extract can be obtained and extraction completed very rapidly, even within minutes. Recovery of the lipid in a chloroform-rich phase can be achieved by addition of equal volumes of chloroform (under certain conditions) and water to produce a two-phase system. The lower (CHC13) phase is subsequently washed with a methanol-water (1 0.9, v/v) mixture to allow removal of a substantial amount of the nonlipid contaminant with little or no problems with interfacial fluff formation or emulsions. However, even though this is a highly efficient method, it is still advisable that one take steps... 

Iverson, S. J., Lang, S. L., and Cooper, M. H. 2001. Comparison of the Bligh and Dyer and Folch methods for total lipid determination in a broad range of marine tissue,... 

Lipid extraction is one of the key steps for the successful analyses of cellular lipidomes by ESI-MS, in general, and by approaches using direct infusion, in particular. Traditionally, lipid samples from biological sources are extracted using a mixture of chloroform and methanol based on the Folch method [17] or the modified method of Bligh and Dyer [18] or other solvent combinations [19, 20]. 

Chromatographic methods are employed to analyze and classify brain lipids. The lipids from brain are generally extracted with a mixture of chloroform and methanol using variations of a method originally described by Folch et al. In most procedures, the tissue or homogenate is treated with 19 volumes of a 2 1 (v/v) mixture of... 

Procedures for isolation and measurement of lipids in foods include exhaustive Soxhlet extraction with hexane or petroleum ether (AOAC, 1995 see Basic Protocol 1), chloro-form/methanol (Hanson and Olley, 1963 Ambrose, 1969), chloroform/methanol/water (Folch et al., 1957 Bligh and Dyer, 1959 see Basic Protocol 2 and Alternate Protocol 2), acid digestion followed by extraction (see Basic Protocol 4), or, for starchy material, extraction with n-propanol-water (e.g., Vasanthan and Hoover, 1992 see Basic Protocol 3). Each method has its own advantages and disadvantages and successful measurement of lipid content is often dictated by the type of sample and extraction medium employed. Commercial extraction and preparation of edible oils are explained in the literature (Williams, 1997). 

Folch, J., Lees, M., and Sloane Stanley, G.H. 1957. A simple method for the isolation and purification of total lipids from animal tissues. J. Biol. Chem. 226 497-509. 

A protocol on lipid extraction modified from the pioneering work of Folch et al. (1957) is included in this unit for convenience (see Support Protocol). The authors laboratory uses this protocol for virtually all kinds of samples, and have found it to be effective with reproducibly high recoveries. Another very popular lipid extraction technique is the Bligh and Dyer method, which uses a 1 1 (v/v) mixture of chloroform/methanol (Bligh and Dyer, 1959). For more information on lipid extraction, the discussion by Nelson (1991) on solvent selection and extraction efficiency is recommended. 

Prior to phospholipid analysis, it is imperative to extract the lipids from their matrix and free them of any nonlipid contaminants. Phospholipids are generally contained within the lipid fraction, which may be recovered by the traditional Bligh and Dyer or Folch extraction procedure (9,22). In any phospholipid extraction method it is recommended to include a rather polar solvent in addition to a solvent with high solubility for lipids. The former is needed to break down lipid-protein complexes that prevent the extraction of the lipids in the organic phase. Traditionally, mixtures of chloroform and methanol (especially 2 1, v/v) have been recommended. These are washed with water or aqueous saline to remove nonlipid contaminants. Comparing the recovery of phospholipids, Shaikh found that the neutral phospholipids PC, PE, SPH as well as DPG were nearly quantitatively extracted by all solvent systems studied (Table 1), although Bligh and Dyer, in which the lower phase was removed only once, was somewhat worse (23). 

However, Shaikh demonstrated that the aforementioned traditional methods are inappropriate to recover completely lysophospholipids as well as acidic phospholipids classical Folch gave 85-90% recovery of LPC and LPE, whereas Bligh and Dyer yielded only 75-80% recovery. Extraction with a mixture of chloroform and methanol, on the other hand, provided nearly complete recovery of acidic and lysophospholipids, but up to 15% losses were observed during subsequent washing, according to Folch. These losses could be circumvented by purification of the crude extract on Sephadex G-25, but this column chromatographic procedure is quite time-consuming. 

Selected examples of analytical methods used for the determination of global profiling of lipids are listed in Table 5. Extraction is usually based on simple liquid extraction, using modified Folch or Blight and Dyer extraction (4,5). For more acidic lipids, such as PSs and phosphatidic acids, adjustment of the pH in the aqueous phase is required. The analysis is most typically performed with LC-MS in RPLC mode, with the UHPLC methods gradually replacing the conventional HPLC methods. HRMS systems, such... 

Total liver lipid was extracted from lyphilized tissue and determined by the method described by Folch et al. (11). Serum total cholesterol and HDL-cholesterol were also enzymatically assayed (12). Fecal fat analyses were performed using the Goldfisch method (13). 

Another advantage of USAL is the need for little or no additional chemicals as compared to classical methods. Such is the case with the USAL of frans-fatty acids from bakery products [32], This method uses n-hexane as leacher by contrast, the Folch reference method requires a chloroform-methanol mixture and additional reagents including sodium chloride to remove non-fat contaminants such as sugars, amino acids and salts, which are co-extracted with the lipid fraction. 

Salivary lipids should be extracted prior analysis by means of chlorophorm-methanol (2 1) according to Folch s method (40). Thereafter, lipids may be separated and quantified with thin-layer chromatography (9) or with gas-liquid chromatography (23). Salivary lipids may also be fractionated with silicic acid column chromatography. 

The stable isotope of carbon, C , is obtained in the form of methane, cyanide or a carbonate. This isotope is available in larger quantities than are the radioactive carbons although highly enriched material is difficult to obtain. Measurements are readily and accurately made with a mass spectrometer. The usual procedure involves combustion of an organic substance containing by the wet oxidation procedure of Van Slyke and Folch or by the usual combustion methods followed by purification of the resulting CO2. The sample of CO2 is then analyzed by means of the mass spectrometer. It should be emphasized at this point that analyses of necessity must be carried out on analytically pure substances since most contaminants contain carbon. This is particularly true of biological substances which have to be isolated from natural sources. 

The unusual solubility behavior of, for example, the Tay-Sachs brain tissues is due to qualitative and quantitative differences in the composition of the appropriate lipid.211 The isolation and purification of these anomalous gangliosides were carried out similarly to those for the gangliosides of normal tissues, for example, by the method of Folch and coworkers.182 In this method, the brain tissues are extracted with chloroform-methanol-water, the extract is washed with potassium chloride solution, and the extracted material is separated on a column of silicic acid by elution with an increasing concentration of methanol in chloroform. 

Folch J., Lees M., Stanley G.H.S., A Simple Method for the Isolation and Purification of Total Lipides from Animal Tissues, Journal of Biological Chemistry 226 (1957) 497-509. 

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