Certified acs grade chloroform

High-performance liquid chromatography (HPLC)/MS grade methanol, acetic acid, and isopropyl alcohol were purchased from Sigma (St. Louis, MO, USA), and certified ACS grade chloroform came from Fisher (Fair Lawn, NJ, USA). Ammonium acetate was of analytical reagent grade and was acquired from Merck (Darmstadt, Germany), and C8 cartridges were obtained from Supelco (Bellefonte, PA). The N-omega-CD3-octadecanoyl GM3 (IS), and GM3 and GD3 ganglioside standards from buttermilk were purchased from Matreya (Pleasant Gap, PA, USA). The stock solutions of both standards were prepared separately in methanol to obtain a concentration of 1 mg/mL. Milli-Q grade water was used for all experiments.

Poly (lactic) acid, Ingeo™ biopolymer 6201D, was purchased from Nature Works (Minnetonka, MN, USA) in pellet form. The PLA thermoplastic fiber-grade resin was derived from annually renewable resources with specific gravity of 1.24, glass transition temperature (T_g) of 55–60 °C, and crystalline melting temperature (T_m) of 150–170 °C (according to the supplier datasheet). The weight-average molecular weight and polydispersity index, adopted from the corresponding author’s previous research findings, determined by Size Exclusion Chromatography (SEC) was 143 kDa and 1.8, respectively [23 (link)]. Cellulose acetate (CA) with a 39% acetyl content and number average molecular weight ( $\overline{M_n}$ ) of 30 kDa, determined by Gel Permeation Chromatography (GPC), was purchased from Sigma-Aldrich (St. Louis, MO, USA). Sodium hydroxide Redi-Dri™ anhydrous ACS reagent grade (≥97%) pellets were also purchased from Sigma-Aldrich. Certified ACS grade chloroform, acetone, and glycerol with a ≥99.9% assay were purchased from Fisher Chemical (Fair Lawn, NJ, USA). Ultrapure deionized formamide was purchased from VWR life sciences (Radnor, PA, USA). Additionally, 300 mm × 300 mm copper gauzes (30-mesh), made with 0.15 mm diameter copper wires, were purchased from Alfa Aesar (Ward Hill, MA, USA). Copper foil (annealed, 99.8% metal basis) with a 0.05 mm thickness was also purchased from Alfa Aesar.