i would like to know the procedure and methods of determination of cyanide in cassava root tubers and leaves?
956466
Try this website : It has all the detailed procedures on preparing the plan and the cyanide testing.\n\nhttp://www.plantphysiol.org/cgi/content/full/139/1/363
886413
Use three test tubes, put equal amout of enzymes in all and put the substance they digest in both (equal amounts of course).\n\ntake a test tube(A) and put 2cm3 of Hydrochloric acid.\nTake test tube (B) and put 2cm3 of Pure water(pH7).\nTake test tube (C) and put 2cm3 of Sodium Hydroxide.\n\nshake them all a little just as you start the test.\n\nLeave them for half an hour at their optimum temperature and other factors.Make sure all factors among them are equal.\n\nAfter that, Test for the substance you put in (e.g test for starch using iodine if you put starch in).\n\nThe one with the most negative result is the optimum pH.
76491
Depends on the soil and what chemical process was used, but mostly plant nutrients. Very helpful website below.
106465
Check out the methods section of this article: http://freenet.macatawa.org/~rimmer/Vitamin.htm\n\nThere are different methods to measure the content of different nutrients.  One of the most common methods is NIR spectroscopy.  And then there are chemical analyses and preparation techniques to isolate certain nutrients. In short, big time biochemistry going on!
148827
Cyanide, arsenic, mercury, pesticides...
609782
root, stem, leaf and flower
610466
Spectrophotometric methods, or those based on the absorption of light by an analytical species, are some of the simplest and most common methods used in quantitative analysis. The amount of light which is absorbed by the sample (A) is correlated with the concentration (c) of the analytical species present using Beer's Law (A = e bc; where e is the molar absorptivity for the analytical species and b is the pathlength of the sample cell). \n\nIn this experiment, the analytical species, iron, will be studied using a colorimetric method in which a reagent is added to transform iron into a highly absorbing complex. Iron is often found in nature in reasonably high concentrations and may enter the hydrosphere through the weathering of iron salts and minerals. Both iron (II) and iron (III) ions are commonly found dissolved in water either in a colloidal form or as inorganic or organic complexes. There are also multiple anthropogenic sources of iron in the environment such as canneries, tanneries, textile mills, and metal cleaning operations. \n\nA relatively simple but sensitive colorimetric procedure for the determination of iron involves first reducing all iron present in the sample to iron (II) ion using hydroxylamine hydrochloride and then complexing with 1,10-phenanthroline in a solution buffered at low pH:\n\nPart 1: Preparation of Iron Standard Solutions\n\nWeigh 351 mg of high quality ferrous ammonium sulfate hexahydrate (FeSO4(NH4)2SO4 Ÿ 6H2O) and quantitatively transfer to a 500 mL volumetric flask. Add 50 mL of distilled water followed by 1 mL of concentrated sulfuric acid. Dilute to the mark with distilled water and mix thoroughly. Using this solution, prepare five standard solutions of iron (II) ion (about 10 - 15 mL should be sufficient) ranging in concentration from 0.5 to 5 ppm.\n\nPart 2: Preparing a Beer's Law Plot\n\nTransfer a 5 mL aliquot of the lowest concentration iron standard solution (probably 0.5 ppm) to a 125 mL Erlenmeyer flask and test the pH with test paper. If the pH is greater than 4.5, add enough 0.2 M sulfuric acid to bring the pH to about 3.5, counting the number of drops that you have added. \n\nAgain, counting the drops that you add, add sodium citrate (259 g/L) buffer to bring the pH to about 4.5. Pipet 1 mL of 10% hydroxylamine hydrochloride and 3 mL of 0.3% 1,10-phenanthroline into the sample and mix the solution well. Allow about 5 min for development of color.\n\nUse the same number of drops of sulfuric acid and sodium citrate for your remaining standard solutions. For each solution, add 1 mL of 10% hydroxylamine hydrochloride and 3 mL of 0.3% 1,10 phenanthroline and mix the solutions well. Allow about 5 min for development of color for each solution.\n\nScan the absorbance of each of the solutions from 300 to 600 nm using the Shimadzu ultraviolet-visible spectrometer, noting the absorbance value of each solution at 510 nm. For each sample, use water as your reference blank.\n\nPart 3: Analysis of samples\n\nWater samples should be measured for each member of your group in addition to determining the iron concentration in an unknown water sample provided by the Instructor. Treat the samples in the same way as the standards: using a 5 mL sample, add sulfuric acid initially, if necessary, to adjust the pH, followed by citrate buffer, reducing agent (1 mL of 10% hydroxylamine hydrochloride), and the indicator (3 mL of 0.3% 1,10 phenanthroline). Mix the solutions well and allow about 5 minutes for development of the complex. \n\nScan the absorbance of each of your sample solutions from 300 to 600 nm using the Shimadzu ultraviolet-visible spectrometer, noting the absorbance value of each solution at 510 nm. Using your Beer's Law plots prepared in Part 2 and the measured absorbances of your samples, determine the iron concentrations in each of your water samples.
439611
Yes!\n\nComparison of the Ammonium Oxalate Extraction of Fertilizer for K2O, Method 983.02, with the Ammonium Citrate/EDTA Extraction, Method 993.31 \nNatalie F. Newlon \n\nThe direct available method for phosphorus in fertilizers, Method 960.03, is an Official Method for extraction of both P2O5 and K2O. Because K2O is much more soluble and easier to extract than P2O5, the conditions of the extraction procedure are set for efficient extraction of P2O5, and the extraction of K2O is, in effect, a bonus. In 1993, a modified extraction procedure, using an extractant of ammonium citrate/ethylenediaminetetraacetic acid (EDTA) solution, was evaluated for P2O5 and then collaboratively studied. This now-modified extraction procedure for phosphorus is Official Method 993.31, which is used extensively as an alternative to Method 960.03 for phosphorus because it is less labor-intensive. Method 993.31 was also evaluated in our laboratory for K2O extraction, but it was never formally collaboratively studied for K2O. To demonstrate the suitability of Method 993.31 as an extraction procedure for K2O, as well as P2O5 in fertilizers, Method 993.31 extraction for K2O was compared with Method 983.02, the traditional ammonium oxalate extraction procedure for K2O. A wide range of fertilizer samples was extracted by using both procedures. The t-test for samples containing <30% K2O had a t-value of 1.23 and a probability of 0.22, which indicates there was no significant difference in the results obtained by the 2 extraction methods. The t-test for samples containing >30% K2O had a t-value of 0.30 and a probability of 0.77, also indicating no significant difference. It is recommended that Method 983.02 be modified to include the ammonium citrate/EDTA extraction procedure as an additional option for extraction of K2O from commercial fertilizers.
261828
http://www.academic.marist.edu/~jfjp/chem351E3.htm\n\nThe alternate would be ion chromatography
724819
To determine the concentration of a reagent.
292599
1. take a mixture of different juices in a cup.\n2. cut a filter paper (coffee filter will do) at the center to make a thin wick.\n3. place the filter paper on top of the juice cup with the wick of the filter paper dipped in the juice.\n\nAfter sometimes you will see that juice has been drawn by the wick and the filter paper will show rings of different colors on it.\n\nThis happens because the flow rate of different components of juice is different. Component that has higher flow rate makes bigger circles than the others.\n\nThis method of seperating different components of mixtures of liquids and analyzing them is called chromatography.
918791
Hmm.  Well, in Safety Education a million years ago, I learned cigarette *smoke* contains hydrogen cyanide, among other yummy things.
863749
Cyanide is an extremely potent inhibitor of the enzyme cytochrome c oxidase (an enzyme of the cytochrome P450 family).  This is part of Complex IV in the electron transport chain.  As a result, oxygen cannot accept an electron completing the chain.
665494
It can be made by dehydration of acrylamide\nCH2=CH-C(O)NH2 --> CH2=CH-CN + H2O\nP2O5 is a good reagent for that.
296040
Hydrogen cyanide is a chemical compound with chemical formula HCN. A solution of hydrogen cyanide in water is called hydrocyanic acid or prussic acid. Pure hydrogen cyanide is a colorless, very poisonous, and highly volatile liquid that boils slightly above room temperature at 26 °C, thereby generating hydrogen cyanide gas. Hydrogen cyanide has a faint, bitter, almond-like odor that some people are unable to smell due to a genetic trait. Hydrogen cyanide is weakly acidic and partly ionizes to become the cyanide ion CN– in aqueous solution, resulting in a colorless volatile liquid with the typical hydrogen cyanide odor. The salts of hydrogen cyanide are known as cyanides.\n\nOther names - Hydrocyanic acid, Prussic acid, Formonitrile,Formic anammonide,Carbon hydride nitride,Cyclon \nMolecular formula - HCN \nMolar mass  -27.03 g/mol \nAppearance - Colorless gas or pale blue, highly volatile liquid \n\nCyanide is used in tempering steel, dyeing, explosives, engraving, the production of acrylic resin plastic, and other organic chemical products. Its use in insect killing jars has now largely been replaced by less toxic ethyl acetate.\n\nMost military sources list hydrogen cyanide among the chemical warfare agents causing general poisoning.
97263
cassava,plantain and oil
387966
The classical method is called Karl Fischer titration.\nIt's a little complex, but it's the generally accepted standard way assaying water content.\n\nThe overall reaction is:\n\nI2 + 2H2O + SO2 --> 2HI + H2SO4\n\nThis is done in the presence of a nitrogenous base (usually pyridine) to neutralize the acid produced. An anhydrous alcohol (often methanol) is used as the solvent. \n\nThe KF reagent is made by dissolving the base, I2 and SO2 in the desired alcohol. The sample is dissolved separately in the same alcohol. The KF reagent is then titrated into the sample solution until the I2 is no longer consumed. If you know how much I2 was required, you can calculate how much H2O was present in the sample.\n\nIn practice, there are machines which fully automate this process, so all you have to do is add your sample and wait for the results.\n\nYou can also weight your sample, dry it in an oven, weigh it again, and assume the difference in weight is due to loss of water. While this method will give an estimate of moisture contant, it doesn't have nearly the same accuracy, precision or specificity as the KF titration.