How to compare Special characters?

Good day all,

I am working out to compare two strings with in single document it works correctly for alphanumerical data but it is not working properly for the special alphabetic values like Cáceres-Martínez. (a & i values)

Can anyone help me to resolve this issue.

This is my code:

StreamReader sr = new StreamReader(this.textBox1.Text);
string strValue = sr.ReadToEnd();
string[] strSpliter =new string[1];
strSpliter[0] = "References";
string[] strSplitValue = strValue.Split(strSpliter, StringSplitOptions.None);
String[] strParaValue = strSplitValue[1].Split(new string[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
FileStream fst = new FileStream(@"E:\TrueText.txt",FileMode.Append);
StreamWriter swt = new StreamWriter(fst);
FileStream fsf = new FileStream(@"E:\FalseText.txt", FileMode.Append);
StreamWriter swf = new StreamWriter(fsf);

swt.WriteLine("Startred on :" + DateTime.Now.ToString("yyyy/MM/dd/hh/mm/ss") + "\n");
swf.WriteLine("Startred on :" + DateTime.Now.ToString("yyyy/MM/dd/hh/mm/ss") + "\n");

foreach (string strPara in strParaValue)
{
string[] strAuthorsPart = strPara.Split('.');
string[] strAuthorslist = strAuthorsPart[0].Split(',');
string[] strAuthor = strAuthorslist[0].Split(' ');
if (strSplitValue[0].Contains(strAuthor[0].Trim()))
{
swt.WriteLine(strAuthor[0] + "\t");
}
else
{

swf.WriteLine(strAuthor[0] + "\t");
}

Thanks

Deepakkumar G.