CFLib.org – MolecularWeight

MolecularWeight(strMolecule)

Last updated March 20, 2002

author

Michael Corbridge
Send Email

Version: 2 | Requires: ColdFusion 5 | Library: ScienceLib

Rated 0 time(s). Average Rating: 0

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:

	
	<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>