MolecularWeight(strMolecule)
Last updated March 20, 2002
Version: 2 | Requires: ColdFusion 5 | Library: ScienceLib
Description:
By entering a valid IUPAC string representing a molecule, the corresponding molecular weight will be calculated. Currently the following elements are parsed: C,O,N,H,K,Na,Ca and Gd - but it is very simple to extend the list.
Return Values:
Returns a numeric value.
Example:
The molecular weight of glucose is
#molecularWeight('C6H12O6')# amu.
</cfoutput>
Parameters:
| Name | Description | Required |
|---|---|---|
| strMolecule | Molecule string. | Yes |
Full UDF Source:
<cfscript>
/**
* Calculates the molecular weight (amu) of input string.
*
* @param strMolecule Molecule string.
* @return Returns a numeric value.
* @author Michael Corbridge (mcorbridge@macromedia.com)
* @version 2, March 20, 2002
*/
function molecularWeight(strMolecule) {
var mw = 0;
var nextChr = '';
var strLen = Len(strMolecule);
var newString='';
var i = 0;
var j = 0;
var n = 0;
var elementArray = arrayNew(2);
var aString = arrayNew(1);
var atom = '';
var elementWeight = 0;
var atomicWeightMultiplier = '';
for(i=1; i LTE strLen; i=i+1)
{
aString[i]=mid( strMolecule, i, 1);
}
arrayAppend(aString,'!');
for(i=1; i LTE strLen; i=i+1)
{
if(aString[i] NEQ '!')
{
newString = newString & aString[i];
nextChr = aString[i+1];
if(nextChr NEQ '!')
{
if(isNumeric(nextChr) OR asc(LCase(nextChr)) IS asc(nextChr))
{
newString = newString & '';
}
if(asc(UCase(nextChr)) IS asc(nextChr) AND NOT isNumeric(nextChr))
{
newString = newString & ',';
}
}
}
}
// input validation
for(n=1; n LTE (arrayLen(aString)-1); n=n+1)
{
for(i=33;i LTE 47;i=i+1)
{
if(chr(i) IS aString[n])
{
return 'invalid input';
}
}
for(i=58;i LTE 64;i=i+1)
{
if(chr(i) IS aString[n])
{
return 'invalid input';
}
}
for(i=91;i LTE 96;i=i+1)
{
if(chr(i) IS aString[n])
{
return 'invalid input';
}
}
for(i=123;i LTE 126;i=i+1)
{
if(chr(i) IS aString[n])
{
return 'invalid input';
}
}
}
elementArray[1][1]='Na';
elementArray[1][2]= 22.989770;
elementArray[2][1]= 'C';
elementArray[2][2]= 12.011;
elementArray[3][1]= 'N';
elementArray[3][2]= 14.6667;
elementArray[4][1]= 'H';
elementArray[4][2]= 1.00079;
elementArray[5][1]= 'O';
elementArray[5][2]= 15.9994;
elementArray[6][1]= 'K';
elementArray[6][2]= 39.0983;
elementArray[7][1]= 'Ca';
elementArray[7][2]= 40.078;
elementArray[8][1]= 'Gd';
elementArray[8][2]= 157.25;
elementArray[9][1]= 'Cl';
elementArray[9][2]= 35.453;
elementArray[10][1]= 'Au';
elementArray[10][2]= 196.96655;
elementArray[11][1]= 'Br';
elementArray[11][2]= 79.904;
// add elements as required
for(i=1;i LTE listLen(newString);i=i+1)
{
for(j=1;j LTE len(listgetat(newString,i));j=j+1)
{
if(isNumeric(mid(listgetat(newString,i),j,1)))
{
atomicWeightMultiplier = atomicWeightMultiplier & mid(listgetat(newString,i),j,1);
}
}
if(len(atomicWeightMultiplier) IS 0)
{
atomicWeightMultiplier = 1;
}
atom = replace(listgetat(newString,i),atomicWeightMultiplier,'');
for(j=1;j LTE arrayLen(elementArray);j=j+1)
{
if(atom IS elementArray[j][1])
{
mw = mw + (elementArray[j][2] * atomicWeightMultiplier);
}
}
atomicWeightMultiplier='';
}
return mw;
}
</cfscript>
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