1：Experimental Design and Method Selection:

A single pulse LIBS setup was used to assess tablet homogeneity. All data were obtained using a nanosecond 1064 nm Nd:YAG Q-switched laser with 50 mJ of laser pulse energy with durations of 8 ns and spot size of 150 μm on the sample surface. The spectral analysis was performed by a CCD spectrometer composed of six detectors with a spectral window of 186 ? 1042 nm (12 288 emission lines with resolution in the range of

2：050 ? 094 nm) with a delay time (between laser pulse and detection) of 1 μs. A xyz translational ablation chamber with a 1280-1024 CMOS color camera imaging system was used to perform the ablation pattern. Sample Selection and Data Sources:

The sample used was a very common medicine found on the Brazilian market, employed for headaches, fever, stressed muscles and pain in general. Its analgesic and antipyretic effects are due to one of its APIs: dipyrone (metamizol, C13H16N30SNa).

3：List of Experimental Equipment and Materials:

Applied Spectra, model J200, USA; Quantel Ultra, USA; Axiom

4：5 software. Experimental Procedures and Operational Workflow:

The chosen region in the target was a 10 × 10 matrix (ablation pattern), where each point received 11 laser pulses. A total of 1100 LIBS spectra in each sample was obtained. The first pulse was used to clean the sample surface and its information was discarded.

5：Data Analysis Methods:

The obtained LIBS spectra were analyzed for each region with a homemade MATLAB routine and the lines of interest (C, Na, Mg and Fe) were identified using the National Institute of Standards and Technology (NIST) database.