ATR-FTIR Spectra of Extracts from Caulerpa spp. and its R script for its Chemometric evaluation

README The present collection of spectra comes from several sample collections conducted in February, April, June, August, October, and December 2022, as well as January 2023, covering one full year to assess seasonal variation and species abundance. Vegetal material was collected at the beach of Dzilam de Bravo, Yucatán, Mexico (21°23′24.3″ N, 88°54′33.9″ W), at depths ranging from 0.5 to 1.5 m, within an area approximately 500 m in length and 50 m offshore. The cleaned material was air-dried at room temperature (RT) for 12 h and subsequently oven‑dried at 45 °C until constant weight was achieved. The dried samples were then milled to a fine powder using a domestic grinder and stored at RT in a dark, dry environment until further processing. Dried and ground algal biomass was extracted by sequential maceration with organic solvents of increasing polarity: hexane (ACS reagent, ≥95.0%, Sig-ma‑Aldrich/Merck, Darmstadt, Germany), dichloromethane (≥99.8%, Sig-ma‑Aldrich/Merck), acetone (HPLC grade, ≥99.9%, Fisher Chemical, Hampton, NH, USA), and methanol (LC‑MS grade, ≥99.9%, Honeywell‑Chromasolv/J.T. Baker, Morris Plains, NJ, USA). Organic fractions were obtained consecutively on the same biomass following an ascending polarity scheme: first hexane, then dichloromethane, then acetone, and finally methanol. After each maceration, the mixture was filtered to recover the liquid phase (supernatant), and the residual solid was briefly air‑dried before proceeding with the next solvent. Each supernatant was concentrated under reduced pressure on a rotary evaporator at ≤45 °C to limit thermal degradation of thermolabile constituents, and the resulting crude extracts were stored at 4 °C in the dark until analysis. FTIR‑ATR measurements were performed on a Nicolet™ iS5 spectrometer (Thermo Scientific, Waltham, MA, USA) equipped with an iD7 ATR accessory fitted with a ZnSe crystal and controlled with OMNIC™ software. Each extract was analyzed in triplicate. Spectra were acquired from 500 to 4000 cm⁻¹, with 32 scans per measurement, automatic background subtraction before each run, and a spectral resolution of 8 cm⁻¹ (data spacing 0.964 cm⁻¹).