Detection of OH-C6 in S0203 using two different methods: A–F (standard tune) and G–J (small molecule tune). (A) BPC chromatogram; (B–F) extracted ion chromatograms of [M + H]+ ±0.5, [M + H]+ ±0.01, [M + Na]+ ±0.01, 102.05495 ±0.01, and 1 × 13C [M + Na]+ ±0.01; (G–I) extracted ion chromatograms of [M + H]+ ±0.5, [M + H]+ ±0.01, 102.05495 ±0.01, and [M + Na]+; (J) MS/HRMS trace of 216.123. M: MS/HRMS Library spectrum of OH-C6 [M + H]+ at 10 eV, N: simultaneously acquired MS/HRMS spectrum at 10 eV; (L) full scan spectrum (small molecule tune); (K) full scan spectrum (normal tune). Samples were analysed with a time difference of two months and thus retention was altered, but constant in the sequence and identical (±0.02 min) to reference standard.