Hplc grade isopropanol

On the second day of sequential sampling, pre-shift and post-shift hand wipe samples were collected from worker’s hands. Two 3”× 3” sterile gauze pads (Dynarex, Orangeburg, NY) were placed in 120 mL amber glass jars (Fisher Scientific, Pittsburgh, PA). Each jar included 6 mL of 99% HPLC grade isopropanol (Fisher Scientific) using an automatic pipette. The jars were then tightly sealed, and stored at approximately 5°C for up to seven days. Samples were collected in a break room or conference room before and after the work shift. During sample collection participants were instructed to grab one of the gauze pads and wipe both sides of their bare hands (the area from the bend of the wrist to the fingertips) for 30 seconds. Then they were instructed to grab the other wipe and repeat the process. Both gauze pads were placed into the same jar, sealed, and stored at refrigerated temperatures until analyzed. At the end of the day, workers were asked how many times they washed their hands that work day and glove use was observed and recorded.

Workers provided pre-shift and post-shift hand wipe samples on the second day of sampling. Sample jars were prepared less than a week before sampling. Two 3”x 3” sterile gauze pads (Dynarex, Orangeburg, NY) were placed in 120 mL amber glass jars (Fisher Scientific, Pittsburgh, PA). In each jar, we pipetted 6 mL of 99% HPLC grade isopropanol (Fisher Scientific). The jars were then tightly sealed and stored at approximately 5°C. Hand wipe samples were collected in a break room before and after the work shift. For sample collection, an industrial hygienist instructed participants to remove gloves, grab one of the gauze pads and wipe both bare hands for 30 seconds. Then they were instructed to grab the other wipe and repeat the process. Both gauze pads were placed back into the jar, sealed, and refrigerated (< 4C) until analyzed. For the post shift hand wipes, workers were asked if they washed their hands since providing the pre shift hand wipe sample. The hand wipe samples were analyzed for TPhP.

All CL standards, as well as the E. coli CL extract, were purchased from Avanti Polar Lipids (Alabaster, Alabama), and used without further purification. The general composition of CL molecules is illustrated in Scheme S1, with the structures and molecular weights of all CL standards highlighted in Table S1. The numbering of carbons in fatty acids is displayed in Scheme S2. A detailed description of the nomenclature and shorthand notation for lipids is also provided in Supporting Information. HPLC-grade methanol and acetonitrile were purchased from EMD Millipore (Billerica, MA). HPLC-grade isopropanol and LC/MS-grade formic acid were purchased from Thermo Fisher Scientific (Waltham, MA). Chloroform was purchased from Sigma-Aldrich (St. Louis, MO). A total lipid extract was prepared from a human papillary thyroid carcinoma, procured through the Cooperative Human Tissue Network, utilizing the Bligh and Dyer total lipid extraction method.^{46 (link)} Samples were diluted in 50:50 Chloroform-methanol to 10 μM for CL standards and 10 ng/μL for the biological extracts.