CFLib.org – Common Function Library Project

MolecularWeight(strMolecule)

Last updated March 20, 2002

author

Michael Corbridge

Version: 2 | Requires: CF5 | 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:

<cfoutput>
The molecular weight of glucose is
#molecularWeight('C6H12O6')# amu.
</cfoutput>

Parameters:

Name Description Required
strMolecule Molecule string. Yes

Full UDF Source:

/**
 * 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;
}
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