In situ calibration of inductively coupled plasma-atomic emission and mass spectroscopy

An apparatus for determining the concentration of an element of interest collected at a remote sampling site, comprising:

• an inductively coupled plasma spectrometer for vaporizing, atomizing, and ionizing at least the element of interest to emit characteristic emissions, the emissions generating an output signal intensity proportional to the quantity of the element of interest in the sample;
• a laser proximate the sampling site;
• a first optical fiber with first and second ends, the first end coupled to the laser and the second end positioned proximate the remote sampling site for directing a laser beam from the laser onto a surface of the sampling site to abate a sample of at least the element of interest;
• an aerosol delivery system containing a carrier gas for delivering at least the element of interest to the inductively coupled plasma spectrometer where at least the element of interest is dissociated, atomized and excited to provide its characteristic optical emissions;
• a volatile calibration gas compound of the element of interest;
• and
• a precision gas metering valve for introducing a series of known quantities of a volatile calibration gas directly into the aerosol stream containing at least the element of interest, the metering valve determining the mass flow rate of the calibration gas and the spectrometer generating an output signal intensity proportional to the quantity of calibration gas and element of interest present in the aerosol so that a standard addition curve of the intensity versus the quantity of calibration gas added can be generated to determine the concentration of the element of interest in the sample.

A method for determining the concentration of an element of interest in a sample contained in an aerosol stream, comprising the steps of:

• providing an inductively coupled plasma spectrometer for vaporizing, atomizing, and ionizing at least the element of interest to emit characteristic emissions, the spectrometer generating an output signal intensity proportional to the quantity of the element of interest in the sample;
• providing an aerosol delivery system for delivering the aerosol stream to the spectrometer;
• measuring them ass flow rate of the aerosol stream;
• introducing a series of known quantities of a volatile calibration gas of the element of interest directly into the aerosol stream using a precision gas metering valve, the spectrometer generating an output signal intensity proportional to the quantity of calibration gas and element of interest present in the aerosol stream;
• determining the mass flow rate of the calibration gas;
• and
• generating a standard addition curve of the output signal intensity versus the quantity of calibration gas added to determine the concentration of the element of interest in the sample.