What are the values needed to calculate the total phenolic content?

Please show me the step-by-step calculation of total phenolic content determination. Given the following: weight of sample  = 0.1 g; Absorbance at 760 nm = 0.342

Standards curve provided the following information: y=11.924x - 0.0307; R²  = 0.9993

Extracts from the 0.1 g sample was diluted 10 times before aliquots were taken for analysis.

Experiment:

Weight of sample: 282g

Weight after extraction: 38g

Amount used in FC assay: 300uL used per reaction at (1mL/mg concentration)

GAE equivalent value: 0.1008

How can I calculate the total phenolic content to express as (mg GAE/g extract)?

Thank you in advance.

I have to find out the total phenolic contents in five different plant extracts. I have read many papers but am unable to understand the calculations how to express total phenolic contents as mg GAE/ gram of dry weight. Please explain the calculations in detail.

Hello All,

I'm doing RNA extraction from cells. I tried both ways by using TRIZOL (with chloroform, and isopropanol) and RNeasy mini kit.

When I use TRIZOL, the RNA concentration is high, however the quality of RNA is not good. The ratio of 260/280 is less than 1.8.

When I use RNeasy mini kit, the RNA concentration is low, however the quality of RNA is good. The ratio of 260/280 is more than 1.8.

Can anyone advise me how to get high RNA concentration with good quality together.

Thank you

I've been conducting RNA extraction from 200 microliters of whole blood using the Purelink RNA Minikit according to the provided instructions. Despite several attempts, I'm consistently obtaining low yields (less than 20ng) with poor quality, indicated by a 260/280 ratio of 3+ and low 260/230 ratios. Unfortunately, I'm unable to switch to a different kit at the moment. Could someone please give me some advice on how to improve both the yield and quality of my RNA extraction?

Hi fellows, I've started a project in a new lab where I have to extract RNA from mice liver, brain, and muscles. Upon dissection I immediately snap-freeze the tissue in liquid nitrogen and store it for later isolation. When I had to isolate, I separated a piece of the tissue frozen in the tube with small tweezers, put it in trizol, and returned the tube to -80C.

I've been reading some places and it occured to me that the tissue must be ground to powder while it's frozen before it's used for RNA isolation in trizol. Can anyone please clarify this procedure (everything you do with the dissected tissue up until you put your sample in trizol and homogenize it)? Why is the tissue ground to powder? How long do you wait after snap freezing your tissue to grind it? What tools do you use? What do you do to make sure you preserve the RNA in your sample? How do you measure 50-100mg of tissue (Trizol protocol says thats the range u should use in 1mL) while avoiding the thawing of the tissue and activation of endogenous RNAses?

Any insight will be appreciated.

I encounter the following problem: I want to send viral RNA for further analysis. As the receiver requires, I must process my samples according to a regular RNA extraction protocol and send the filtered spin columns from the RNA extraction kit, without performing the final elution step. But I don't have the original sample preserved, only the RNA already extracted is stored. Can I do a re-extraction using the stored eluate as the starting material?

Although standard betanin pigment is soluble in water, it is getting spread on a TLC sheet. So what can be done in this case?

Every time I conduct protein crystallization experiments, it takes a considerable amount of time, often extending into the late hours of the night. Therefore, I am considering flash-freezing the purified protein samples in liquid nitrogen and storing them in a -80°C freezer. The idea is to thaw them the next day and continue the experiments. Is this approach viable?