Identification of alloys using single shot laser ablation inductively coupled plasma time-of-flight mass spectrometry

Abstract

Single shot laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOFMS) has been developed as a method for the rapid identification of alloy samples. This technique provides good accuracy for elemental concentrations greater than 0.1 percent by mass from samples with a range of different matrix compositions. Through the simultaneous measurement of all elements present within a cloud of ablated particles, relative percent composition values are measured that can be directly compared with certified concentrations. Cluster analysis has been used to successfully classify 33 metal alloys based on the measurement of 15 elements. Additionally, cluster analysis was used to identify the samples from a library of standard reference values. For the 15 alloys used to train this method, the correct standard was identified in greater than 99% of measurements. The only failed identification in the training set may have been due to elemental fractionation experienced with a brass sample. For the 18 standards used to validate the technique, samples were identified with a 93% success rate. Misidentifications may have been caused by inaccurate certified data. Several alloys investigated in this study were less than 500 µm in length at their largest dimension and weighed less than one milligram.