ICP-OES as a Viable Alternative to ICP-MS for Trace Analysis: Meeting the Detection Limits Challenge

This month’s column focuses on the applicability of inductively coupled plasma–optical emission spectroscopy (ICP-OES) fitted with a high efficiency nebulizer as a real-world alternative to ICP–mass spectrometry (ICP-MS) for certain applications. It is well-recognized that ICP-MS is the most widely used and recommended technique for ultra trace element analysis because it offers extremely high sensitivity. However, if the necessary sensitivity is achieved, an ICP-OES instrument can be a viable option because it is simpler to operate and less costly to maintain than an ICP-MS instrument. In this study, the sensitivity of ICP-OES was significantly enhanced by using a highly efficient yet robust sample introduction system. The increased efficiency was accomplished by employing an external impact surface positioned close to the nebulizer gas orifice at an optimized angle. The robustness by a non-concentric design was achieved by separating the gas and sample channels throughout the entire body of the nebulizer. The results of applying this approach to the ICP-OES analysis of a select group of sample matrices and meeting the required challenging detection limits are demonstrated.