Extraction manual shake

Attention is directed to the great advantage of continuous extraction over manual shaking in a separatory funnel for liquids or for solutions which tend to froth or which lead to emulsification comparatively little difficulty is experienced in the continuous extraction process. 

Procedure manually shake the sample bottle for 5 min to homogenize contents and take sample for analysis directly from the bottle. Operations should be carried out at 20 2°C. Weigh 10.00 g soil into a 250 mL polyethylene bottle add 100.0 mL of 0.01 mol L CaCl2 solution and extract on shaker for 3 h at 30 rpm decant about 60 mL into a centrifuge tube and centrifuge for 10 min at 3000 g measure and report the room temperature before and after the extraction and also the temperature of the extracting solution at the end of the extraction measure pH in the extract before centrifugation analyse immediately. 

Procedure manually shake the sample bottle for 1 min to homogenize contents and take sample for analysis directly from the bottle. Weigh accurately 40 g soil and extract in extraction bottle with 100 mL of 0.1 mol L NaN03 solution at 20 2 °C for 2 h at 120 rpm. Centrifuge for 10 min at 4000 g remove the supernatant by syringe fit the membrane filter and filter into 50 mL bottle add 2 mL cone. HNO3 to 50 mL volumetric flask and make up to volume with filtered extract (prevention of microbial growth) analyse immediately (note that solutions are stable for 1 week at 20 5 °C). 

Classical solvent extraction Blending (mixing, shaking) with a solvent at room temperature and normal pressure Organic solvent(s) blenders, probes, shakers, or manual shaking... 

A simplified procedure for detecting the M. aeruginosa toxins was devised. A 20.0 mg sample of lyophilized cells was extracted for 1 hr with 1 ml of 38% ethanol, 5% n-butanol, 50 mM ammonium acetate pH 6.0, shaking the suspension manually for a few seconds several times. The suspension was then centrifuged (5 min at 12,000 Xg). 

As shown in Table 19.2, extraction with the mixture of methanol-water provides adequate extraction efficiency for most of the samples. However, this technique should be automated and the duration of sample preparation should be reduced. The usual methanolic extraction is carried out with the help of a shaking device and the total time of sample preparation including centrifugation and manual separation of the phases may be as long as 10-12 h. Recently, two new techniques have been introduced that can replace the traditional approach, that is, the accelerated solvent extraction (ASE), sometimes referred to as pressurized liquid extraction (PLE), and the MW assisted extraction (MAE). 

Other manual methods include a solid-liquid extraction, which consists of placing the solvent in a tube with sample and shaking the sample and filtering. This method is also called the shake-filter method. The solvent may be heated to improve extraction efficiency. Several other simple methods include sonica-tion of the sample with an ultrasonic probe and heated solvent, and dissolution of the sample directly with solvent (Majors, 1996). 

The ELISA kits are based on the use of selective antibodies raised against specific PAHs, which are attached to a solid matrix support. These are combined with sensitive enzyme reactions (see Section 6.4.4). The kits provide high selectivity and can provide an immediate answer on site, but the disadvantages are that they can be difficult to use in the less than ideal conditions on site and they can only usually give a range of concentrations, e.g. >50, 20-50, 1-20 or <1 mg/kg of total PAHs and mainly rely on a manual rapid cold shake extraction technique which may only extract a small fraction of the PAHs in some samples. In addition, the test kits can prove quite expensive for a screening analysis. 

Extraction can be done either in discontinuous mode in separatory funnels with manual or mechanical shaking and small volumes of water (100 ml to 1 1), or in continuous mode using pieces of apparatus specially designed for large volumes of water (up to 20 1) (Table 23.2). When the distribution coefficient is low and the sample very dilute, a large volume of water is needed and extraction should be done by the continuous liquid-liquid method. 

About 50 mg sample was wetted with 1 mL NaCl solution (standard additions were carried out at this stage) and shaken manually for 15 min this was followed by an addition of 200 pL (sub-boiling distilled) HCl and 20 min shaking. Neutralization was performed by addition of ca. 2 mL NaOH (1 mol L ) to pH 6-7. The extraction was by addition of 1 mL buffer (pH 9)... 

Weigh, to the nearest 0.001 g, approximately 0.3 g of the dried plant material sample into a polycarbonate test tube. If Si has to be measured, 0.15 g K SiF can be added as a check (see remark 1). Add 10 mL of extraction mixture (4.3) and moisten the plant material by shaking manually. Prepare also a blank extraction. 

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