Regex for whitespace-flanked multi-analyte separators
Source:R/cleaning_pipeline.R
multi_analyte_separator_pattern.RdSingle source of truth shared by precheck_multi_analyte(),
flag_multi_analyte(), and suggest_multi_analyte_parts() so the
three stay in lockstep. Matches naked + (not in parens) and
and anywhere, plus & and / only when the separator
is not inside a parenthetical group – so "endosulfan (alpha & beta)" is left
intact while "acetone & ethanol" and "toluene / benzene" split. All
separators require flanking whitespace, which excludes units and ratios such
as mg/L, w/w, and 1.5/1.