Publication details
Rapid Determination of Lead in Submicroliter Samples of Whole Blood using Diode Laser Thermal Vaporization
| Authors | |
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| Year of publication | 2012 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | A method for determination of trace elements in submicroliter sample volumes, diode laser thermal vaporization (DLTV) inductively-coupled plasma mass spectrometry (ICP-MS) is presented. Analyte is desorbed from a substrate, such as paper or cellulose containing a suitable absorber, using a continuous-wave diode laser. The laser induces pyrolysis of the substrate and the generated aerosol is carried out into the plasma torch. Unlike laser ablation, DLTV does not require an expensive high-energy pulse laser, which makes it a promising alternative to nebulizers. Analysis of lead in whole blood is demonstrated. Advantages of the method, simplicity, speed, easy archiving and transportation of samples and low cost, are presented. Selection of experimental arrangement and laser wavelength as well as optimization of experimental conditions, e.g., raster type, scan speed, additives etc. was examined. An arrangement employing common paper as the substrate, commercial printer black ink as the absorber and 808 nm diode laser was chosen. The limits of detection of Co, Ni, Zn, Mo, Cd, Sn and Pb deposited on the pre-printed paper were found to be in a low pg range. The technique was applied to determination of lead in whole blood without any sample treatment. Analysis of 200 nl samples of certified reference whole blood yielded lead concentration 45+-3 ug/L, which is excellent agreement with the theoretical value 46+-5 ug/L. In addition to the commercial ablation chamber, we also designed a simple tubular chamber equipped with a more powerful diode laser. Rapid line scans across a calibration set and unknown samples can be performed with the prototype chamber placed on a common syringe pump; overall duration of the analysis is ~1 minute. DLTV ICP-MS was found to be suitable for quantitative elemental analysis of low volume samples (typically 100 – 500 nL). The method does not require an expensive high-energy pulse laser and ablation chamber. |
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