Uplc grade acetonitrile

High purity pesticide (>98%) standards of ethephon, glufosinate, fosetyl, phosphonic acid, glyphosate, and hydroxyethyl phosphonic acid (HEPA) were purchased from LGC‐Dr. Ehrenstorfer (Augsburg, Germany), N‐acetyl‐AMPA, N‐acetyl‐glufosinate, N‐acetyl‐glyphosate, and 3‐methylphosphinicopropionic acid (MPPA) from Toronto Research Chemicals, TRC (North York, Canada), aminomethyl phosphonic acid (AMPA) was purchased from Sigma–Aldrich (Steinheim, Germany) and bromide, chlorate, and perchlorate were obtained from Inorganic Ventures (Christiansburg, Virginia, USA). Isotope–labeled internal standards, AMPA ¹³C ¹⁵N, ethephon D₄, fosetyl–aluminum D₁₅, HEPA D₄, glufosinate D₃ hydrochloride, N‐acetyl‐glufosinate D₃, MPPA D₃, glyphosate 1,2‐¹³C₂, ¹⁵N, and N‐acetyl‐glyphosate D₃ were purchased from LGC‐Dr. Ehrenstorfer was obtained from Toronto Research Chemicals. Phosphonic acid‐¹⁸O₃, ¹⁸O₃‐chlorate, and ¹⁸O₄‐perchlorate were supplied by the EURL‐SRM in Stuttgart, Germany. HPLC‐grade water from a Water Purification System of Millipore (Burlington, MA, USA) was used. Formic acid was purchased from VWR (Lutterworth, United Kingdom) and trifluoroacetic acid (TFA) was obtained from Merck (Darmstadt, Germany). UPLC‐grade acetonitrile and LC‐grade methanol were supplied by Biosolve (Dieuze, France) and Merck (Darmstadt, Germany), respectively.