Amino Acids

The scraped layer corresponding to each spot is extracted with 70% ethanol in a known minimum volume, and ninhydrin reaction is performed followed by spectrophotometry. Six to eight standard dilutions in an appropriate concentration range for each amino acid are prepared; 2 mL of amino acid solution and 2 mL of buffered ninhydrin are mixed in a test tube, heated in a boiling-water bath for 15 min, cooled to room temperature and 3 mL of 50% ethanol is added. The extinction is read at 570 nm (or 440 nm for proline) after 10 min. Standard plots of concentration versus absorbance are drawn for each amino acid. Materials consist of standard solutions of amino acids, acetate buffer (4 mol L_1, pH 5.5), ethanol (50%), methyl cellosolve (ethylene glycol monomethyl ether), and ninhydrin reagent (0.9 g ninhydrin and 0.12 g hydrantin dissolved in 30 mL methyl cellosolve and 10 mL acetate buffer, freshly prepared). The concentration of the unknown sample is read from the standard plots. TLC densitometry can be used to determine 0.5 mg L_1 of phenylalanine in blood as an indicator of phenylketonuria.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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