String s = "0.13131E+3";
Double d = Double.Parse(s, CultureInfo.InvariantCulture);

Decimal number;
var value = "0.13131E+3";
if(!Decimal.TryParse(value, NumberStyles.Any, CultureInfo.InvariantCulture, out number)) 
   Console.WriteLine("Parsing failed");

string value;
            double number;

            // Parse a floating-point value with a thousands separator.
            value = "0.13131E+3";
            if (Double.TryParse(value, out number))
                Console.WriteLine(number);
            else
                Console.WriteLine("Unable to parse '{0}'.", value);