The extraction conditions such as extractant mixture composition, extraction time and extractions number, were optimized and the need of an extract freezing step previous to SPME is discussed.
For aqueous extract, freeze-dried powder was extracted with 20 mL of water, 20 mM of diethyldithiocarbamic acid and 0.5% formic acid, whereas, absolute methanol was used for methanolic extract preparation.
After 10 min, heart, skeletal muscle, adipose tissue and liver were rapidly extracted, freeze clamped in liquid nitrogen and homogenized as described previously [28].
Once all the liquid is extracted, freeze for 40 minutes.
The brain is then extracted, frozen and shaved into wafers, microns thin, by a device resembling a mini cold-cut slicer.
Egg-freezing -- the medical term is oocyte cryopreservation -- is the technological process during which a woman's eggs are extracted, frozen and stored for safe-keeping.
Birds were killed via rapid decapitation, and brains were quickly extracted, frozen on liquid nitrogen and stored at −80°C until use.
Tissues were extracted, frozen in liquid nitrogen and stored at −80°C.
At 10 minutes after injection, tissues were extracted, frozen in liquid nitrogen and stored at −80°C.
Serum was extracted, frozen at −20°C and later sent to the veterinary laboratory Synlab Vet in Geesthacht, Germany, for determination of blood chemistry parameters.
Flowers at all these stages were collected during three independent weeks to have biological replicates, the carpels were extracted, frozen in liquid nitrogen and stored at -80°C.
