Laser ablation inductively coupled mass spectrometry offers rapid quantitative elemental and isotopic characterization of a myriad of materials. In order to quantify the elemental and isotopic species present in the sample particularly for limited mass samples such as particulates, the entire process from laser ablation through detection in the mass spectrometer must be calibrated. This can only be achieved by creating standards which have known mass and spatial dimensions. Such standards can be created using droplet-on-demand technology such as TIPS (thermal inkjet picofluidic system) which can control both the mass and spatial dimensions of the deposited liquid droplet. This work demonstrates the use of TIPS for calibration of a fs-LA-ICPMS instrument over 6 orders of magnitude ranging from the attogram to nanogram levels for uranium isotopes 235 and 238. In this demonstration, aqueous depleted uranium solutions were deposited onto a silicon substrate using a 300 picoliter volume and creating a 10 x 10 array spaced 500 micrometers apart. The dried spots were about 80 micrometers in diameter. The femtosecond laser spot size was adjusted to match the dried spot deposit. Both individual droplet ablations and entire array ablation of 25 dried residue deposits were sampled. The results show a linear relationship for both 235 and 238 U isotopes with an accurate isotopic ratio of 0.00202 average SD 4.01e-5 for the 235/238 uranium isotopes over the calibration range of 0.03 to 3,000 pg of deposited depleted uranium. This approach can be used with multielement depositions as well as calibrating LIBS sampling for quantification. LA-UR-14-27858

Calibration of femtosecond laser ablation inductively coupled plasma mass spectrometer using a thermal inkjet picofluidic system for sensitive isotopic nuclear material characterization

249th National Meeting (2015)

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