Method of preparing an organic material sample for LIBS analysis and a searing device for use in the same

A method of preparing an organic material sample for laser induced breakdown spectroscopy, the method comprising:

• a. obtaining a sample of granular organic material, the granular organic material having an organic matrix;
• and
• b. searing the sample of granular organic material to produce a searing event during which the organic matrix undergoes a thermochemical decomposition, wherein the searing the sample of granular organic material includes
• (i) supplying heat to the sample of granular organic material for one or more known exposure times (TN) to produce a same number (N) of one or more searing instances (Sn) of the sample of granular organic material;
• (ii) measuring reflectance values (RN) of the sample of granular organic material before and after producing one or more of the one or more searing instances (Sn) of the sample of granular organic material;
• (iii) determining, by a data processor, a searing parameter (X) as an indicator of a susceptibility of the organic matrix to searing determined based on the measured reflectance values (RN);
• (iv) calculating, by the data processor, a time value (Tcorr) indicative of a time to achieve an optimum exposure time from an application, by the data processor, of a predictive model derived from an empirical analysis of reference data comprising time values indexed against searing parameter to the searing parameter (X), the predictive model linking the searing parameter (X) to the time value (Tcorr);
• (v) generating, a new exposure time (TN+1) using the time value (Tcorr);
• and
• (vi) heating the sample of granular organic material for the new exposure time (TN+1) to produce a new searing instance of the sample of granular organic material.