Understanding Parts Per Million

PPM conversion values and serial dilutions : Ppm concentrations and percentages. Ppm to Molarity and Molarity to ppm. HOME Email Webmaster Related link 1000ppm AA Stds. PPM = parts per million PPM is a term used in chemistry to denote a very, very low concentration of a solution. One gram in 1000 ml is 1000 ppm and one thousandth of a gram (0.001g) in 1000 ml is one ppm. One thousanth of a gram is one milligram and 1000 ml is one liter, so that 1 ppm = 1 mg per liter = mg/Liter. PPM is derived from the fact that the density of water is taken as 1kg/L = 1,000,000 mg/L, and 1mg/L is 1mg/1,000,000mg or one part in one million. OBSERVE THE FOLLOWING UNITS 1 ppm = 1mg/l = 1ug /ml = 1000ug/L ppm = ug/g =ug/ml = ng/mg = pg/ug = 10 -6 ppm = mg/litres of water 1 gram pure element disolved in 1000ml = 1000 ppm PPB = Parts per billion = ug/L = ng/g = ng/ml = pg/mg = 10 -9 Making up 1000 ppm solutions 1. From the pure metal : weigh out accurately 1.000g of metal, dissolve in 1 : 1 conc. nitric or hydrochloric acid, and make up to the mark in 1 liter volume deionised water. 2. From a salt of the metal : e.g. Make a 1000 ppm standard of Na using the salt NaCl. FW of salt = 58.44g. At. wt. of Na = 23 1g Na in relation to FW of salt = 58.44 / 23 = 2.542g. Hence, weigh out 2.542g NaCl and dissolve in 1 liter volume to make a 1000 ppm Na standard. 3. From an acidic radical of the salt : e.g. Make a 1000 ppm phosphate standard using the salt KH2PO4 FW of salt = 136.09 FW of radical PO4 = 95 1g PO4 in relation to FW of salt = 136.09 / 95 = 1.432g. Hence, weigh out 1.432g KH2PO4 and dissolve in 1 liter volume to make a 1000 ppm PO4 standard. Click this link for Atomic absorption standards Dilution Formula : C1V1 = C2V2 This equation applies to all dilution problems. C1 (initial conc) x V1 (initial volume) = C2 (final conc) x V2 (final volume) Example : What volume of 6.00 ppm solution must be used to give 4.00 liters of a 0.100 ppm solution? C1 = 6.00 ppm V1 = unknown C2 = 0.100 ppm V2 = 4 liters = 4000 mls V1 = (C2 x V2) / C1      = (0.100 X 4000) / 6.00      = 400 / 6.00 = 66.7 mls. This means that 66.7 mls of the 6.00ppm solution diluted to a final volume of 4 liters will give a concentration of 0.100 ppm. The Formula below can be used to calculate the the V1 component only. req is the value you want. req ppm x req vol -------------------------- = no of mls for req vol          stock Example : Make up 50 mls vol of 25 ppm from 100 ppm standard. 25 x 50 / 100 = 12.5 mls. i.e. 12.5 mls of 100 ppm in 50 ml volume will give a 25 ppm solution Serial dilutions Making up 10-1 M to 10-5 M solutions from a 1M stock solution. Pipette 10 ml of the 1M stock into a 100 ml volumetric flask and make up to the mark to give a 10-1 M soln. Now, pipette 10 ml of this 10-1 M soln. into another 100 ml flask and make up to the mark to give a 10-2 M soln. Pipette again, 10 ml of this 10-2 M soln. into yet another 100 ml flask and make up to mark to give a 10-3 M soln. Pipette a 10 ml of this 10-3 M soln. into another 100 ml flask and make up to mark to give a 10-4 M soln. And from this 10-4 M soln. pipette 10 ml into a 100 ml flask and make up to mark to give a final 10-5 M solution. Molarity to ppm Convert molar concentration to grams per liter (Molarity x Atomic mass of solute), then convert to milligrams per liter (ppm) by multiplying by 1000. e.g. What is the ppm concentration of calcium ion in 0.01M CaCO3? Molarity(M) x Atomic mass(At Wt) = grams per liter(g/l) Atomic Mass (Wt.) of Ca = 40 0.01M x 40 =0.40 g/l 0.40g/l x 1000 = 400 mg/l = 400ppm Note: The FW of an ion species is equal to its concentration in ppm at 10-3M. Fluoride has a FW of 19, hence a 10-3M concentration is equal to 19ppm, 1M is equal to 19,000 ppm and 1ppm is equal to 5.2 x 10-5M. Go here for ISE molarity/ppm conversions shown in Table III. PPM to Molarity Convert ppm to gram based or milligram based concentration. ppm = 1 mg solute per liter solution or ppm = 0.001 gram per liter solution e.g. What is the Molarity of 400ppm Ca ions in an aqueous CaCO3 solution? Using the 0.001g/l concentration: 400ppm x 0.001g/l = 0.4g/l. or, Divide 400 mg by 1000 to get g/l = 0.4 g/l Now divide by the At. Mass of Ca to get Molarity. 0.4g/l divided by 40g/mol =0.01M Using the mg/l concentration, the 40g Ca must be converted to milligrams by multiplying by 1000 to give 40,000mg. Hence Molarity = 400ppm divided by 40,000mg/mol = 0.01M Ppm (parts per million) to % (parts per hundred) Divide the ppm amount by 1,000,000 and multiply by 100 to get %. e.g. : 1 ppm = 1/1,000,000 = 0.000001 = 0.0001% 10 ppm = 10/1,000,000 = 0.00001 = 0.001% 100 ppm = 100/1,000,000 = 0.0001 = 0.01% 200 ppn = 200/1,000,000 = 0.0002 = 0.02% 5000 ppm = 5000/1,000,000 = 0.005 = 0.5% 10,000 ppm = 10000/1,000,000 = 0.01 = 1.0% 20,000 ppm = 20000/1,000,000 = 0.02 = 2.0% (Parts per hundred) % to ppm Divide the % value by 100 and multiply by 1,000,000 to get ppm. e.g. : 1% =0.01 x 1,000,000 = 10,000 ppm 0.5% =0.0.005 x 1,000,000 = 5,000 ppm 0.1% =0.001 x 1,000,000 = 1,000 ppm 0.01% = 0.0001 x 1,000,000 = 100 ppm delloyd.50megs.com