hi... find these articles informative...

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC440148/pdf/plntphys00328-0137.pdf (FIELD METHOD FOR ESTIMATING NITRATE, PHOSPHATE, AND POTASSIUM IN PLANTS)

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC542985/pdf/plntphys00127-0165.pdf (Estimation of Potassium Recirculation in Tomato Plants by Comparison of the Rates of Potassium and Calcium Accumulation in the Tops with Their Fluxes in the Xylem Stream)

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC439909/pdf/plntphys00348-0102.pdf (THE ADAPTATION OF CERTAIN COLORIMETRIC METHODS TO THE ESTIMATION OF NITRATES, PHOSPHATES AND POTASSIUM IN PLANT SOLUTIONS)

The best, quick and cheap method is flame photometry, otherwise you can do titration, but it is more boring.

http://tera.chem.ut.ee/~koit/arstpr/nak_en.pdf, see this article, very simple.

Refer to APHA (book)

Use atomic absorption AA

Thank you all..

I look for the simple way..

May your article could help me..

The simplest method is determination of K by flame photometer. U can start by taking 1 to 5g Ur dried powdered plant material and prepare its ash solution by heating it up to 600C in furnace, dissolve it in 10 ml HNO3 and heat for 30 mints to reduce the volume about 2ml then add deionized or distilled water ,filter through a watt man filter paper and check it by flame photometer .for detail check AOAC BOOK

Unfortunately, my laboratory doesn't have a flame photometer..

how to check with a very simple way??

Check these links they will help

1. Http://www.jbc.org/content/121/2/631.full.pdf

2. Http://www.jbc.org/content/156/2/743.full.pdf

3. Http://www.ofite.com/products/285-30.asp

if u have pH meter in your lab you can determine potassium by K ion selective electorode

Could u explain the steps?

You have to follow the above cited method in my first comment.but prepare your sample solution of known quantity of deionized water i.e for example prepare your ash sample solution up to 50 ml or 100ml

then follow the following link

www.omega.com/manuals/manualpdf/M0781.pdf

Isolates could be analyzed with ICP spectrometry, but the instrument is pretty expensive. Probably depends on the concentrations you are expecting to see. If they are greater than ppm, a cheaper method would probably be fine.

Dear Muhammad Siddique,

very nice PDF

Thanks, dear Kiran Pund u r welcome

Andita, I don't know if you found a method. But I use a hand held (iSTAT - point of care machine used in ICUs) machine that is used to measure blood electrolytes and arterial blood gases. The machine uses 'use and throw' cartridges, so there is no damage to the electrode, which may occur with a larger machine used in a clinical biochem lab. Since the plant extracts are rich in potassium (for eg, about 70 mM in a solution of about 700 mosm/L, you must dilute your sample so that its osmolarity is less than 100 mosm/L, to get the K conc to the range of serum K. (The electrolyte analyzers used clinically can measure upto 15 mM potassium I think). Then it is just load and read in 45 seconds.

Thank u for ur information siddique..........................

thank you all

I think the plant extracts are low in potassium

no K and Na are present in plants in large quantities as compared to other metals

by atomic absorption spectrophotometry can measure K but first you should identify the type of plant for good ashing and preparation of sample

You just go through this paper.evaluation of triacid and dry

ashing procedures for determining potassium, calcium, magnesium, iron, zinc, manganese,

and copper in plant materials

k. L. Sahrawat,* g. Ravi kumar, and j. K. Rao

Inductively coupled plaspa (ICP) spectrophotometry can measure potassium and does not require ashing of the samples. ICP can measure multiple elements at the same time. An aqueous or organic extract of the plant and a potassium standard is all that would be needed.

Hi! I could provide you fluorescent potassium-sensitive capsules. These capsules are taken up by cells and can measure intracellular concentration of potassium and other ions (protons and sodium).

http://onlinelibrary.wiley.com/doi/10.1002/smll.201001144/abstract

kind regards

Loretta

Thank you all..

Manuel BORRERO CEDEÑO : actually, i do not understand your language. but, anyway, thank you very much

thank you loretta