Extraction homogenizer-assisted

Polyphenolics Alternate Protocol 1 Homogenizer-Assisted Methanol Extraction of 11.2.1... 

The ultrasound-assisted extraction of freeze-dried plant-based materials normally takes 2 hr. If the extract is evaporated to dryness, a total of 3 hr is necessary. As an additional sample preparation step, 2 to 4 days should be allotted for freeze-drying fresh plant materials, depending on the quantity of the material. Homogenizer-assisted extraction of fresh fruit takes <4 hr. 

Extraction of solid samples Homogenization extractions Sonication extractions Microwave assisted extractions Soxhlet extractions Accelerated solvent extractions Supercritical fluid extractions Extraction of liquid samples Liquid-liquid extractions Solid phase extractions (SPE)... 

BDE 47, 99 100 Fish (Muscle tissues of salmon and conger eel and liver tissues of sea bass) green mussel Homogenization, MSPD with sodium sulfate, microwave-assisted extraction with pentane-dichloromethane (1 1) and purification with GPC Gas Chromatography (DB-5MS) Q-MS <100 ng/Kg [41]... 

Extraction of samples. Plant tissues were lyophilized after harvest and ground to a homogeneous powder in a Wiley mill (no. 20 mesh). Samples (0.500 g) of lyophilized whole leaf were extracted in 125 mL roundbottom flasks by steeping in 25 mL of chloroform for 30 min. The extract was filtered and the filtrate set aside. The extraction flask and filtered solids were rinsed with an additional 15 mL of fresh chloroform. The filtrate from the rinse was then combined with the original filtrate and the resulting solution was evaporated to dryness with a rotary evaporator. The dry solids were redissolved in a mixture of 20.0 mL methanol and 5.0 mL acetone using sonication to assist in dissolving of all solid material. 

Having accomplished the homogenization of the sample, extraction of free amino acids is usually a simple process of stirring the sample in an appropriate solvent. This is typically a dilute solution (0. IN) of hydrochloric acid (2,7). Elevated temperatures may be used to assist dissolution, but care must be taken not to damage the more acid-labile amino acids. More recently, Moret and Conte (8) report that 0.1N HC1 was not a suitable solvent for all types of food samples. For some types of meat samples, 5% trichloroacetic acid is reported to afford superior performance (for biogenic amines, also amino acids ). It is not unusual to see perchloric acid employed for extraction from meat tissues (also more commonly for biogenic amines). 

A variety of solvent extraction techniques have been used to extract antioxidants from food matrices. The most commonly used is maceration or homogenization of the sample with an extraction solvent however, alternative procedures have been developed including pressurized fluid extraction (PFE), ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and matrix solid-phase dispersion (MSPD), among others. The principles of each extraction technique will be briefly discussed. 

Soil, sediment, and dust samples were prepared in a similar way before analysis. After the pre-cleanup steps and homogenization, FRs were extracted from samples using different solid-liquid extraction techniques. The most commonly used technique was accelerated solvent extraction (ASE), which enables the fast extraction of samples using different solvents such as hexane and dichloromethane [98-100]. Other commonly used techniques for these samples were ultrawave-assisted extraction (UAE) [97], which also enabled quick extraction, and the more time-consuming but very efficient technique, Soxhlet extraction [96]. Some authors have also described less common techniques such as microSPE [95]. There is also information that many FRs that are no longer produced (mainly PCBs and PBDEs) are present in dusts, soils, and sediments in very high amounts, even 390 pg/g [98]. 

Chapter 6 is oonoerned with analytical steps involving liquid samples (or liquids resulting from the steps disoussed in Chapters 3 and 4). Thus, liquid-liquid extraction, emulsi-fioation and homogenization, among others, can be assisted by US under appropriate conditions. 

The alcohol substrate and at low partial pressure are dissolved in the homogeneous scCOj phase which, upon contact with the powdered sol-gel entrapped catalyst, spills the reactants into the pores where the oxidative dehydrogenation takes place. It then extracts the products. Furthermore, the RuO " immobilization at an imidazolium-modified surface which acts as a potent solubilizing agent accelerates substrate/product dissolution and thus the reaction rate. As evident by the smooth oxidation of the less reactive primary aliphatic alcohol, 1-octanol, a versatile active catalyst is obtained that can be used for the fast conversion of different substrates. Moreover, scCO assists in water removal (thus preventing aldehyde hydration and overoxidation) through its well-known ability of drying solid matrices. 

The homogeneity was verified by repeated determinations of total As, arsenobetaine and DMA. The total As content was determined by HG-QFAAS after microwave assisted digestion, whereas DMA was determined by HPLC-ICP-MS. The within-bottle homogeneity was assessed by 10 determinations in each of two bottles, and the between-bottle homogeneity was evaluated by two determinations out of each 20 bottles the method uncertainty was evaluated by five replicate determinations of a digest or extract solution. The within- and between-bottle CV ranged from 0.5 to 1.2% for total As, from 2.1 to 5% for arsenobetaine, and from 7.1 to 10.6% for DMA, which was comparable to the method uncertainty (respectively 2.6, 3.1 and 6.8%) therefore, no inhomogeneity was suspected at a level of 0.3 g for total As and 1 g for As species, and the material was considered to be suitable for use as a CRM. 

Akhtar MH, Comparison of microwave assisted extraction with conventional (homogenization, vortexing) for the determination of incurred salinomycin in chicken eggs and tissues, J. Environ. Sci. Health B 2004 39 835-844. 

Determination of MC in cyanobacteria, algae, or tissues requires the optimization of additional step in analytical procedure—liquid extraction from these materials. In analysis of cyanobacterial cells, they are most often lyo-philized and then extracted with 75% methanol or with 80% ACN with addition of formic acid."" Double extraction with 75% methanol was also employed for homogenates of algae and fish tissue." In another procedure, extraction of cells with 25% methanol" or 5% acetic acid"° is assisted by sonication. The use of acetic acid instead of methanol is advantageous because of more... 

---