Reagent grade or better. In this evaluation, benzene-free CS 2 was used. Fifty grams of molecular sieve should remove the benzene from 1 L of carbon disulfide. Reagent grade or better. Sodium sulfate, anhydrous.
Sodium sulfate is used as a drying agent.
An internal standard such as ethyl benzene can be used. Standard preparation 3.3.1. Prepare working analytical standards by injecting microliter amounts of concentrated stock standards into 2-mL vials containing 1 mL of desorbing solution delivered from the same dispenser used to desorb samples. Prepare a sufficient number of analytical standards to generate a calibration curve. Ensure that the amount of 2-butanone found in the samples is bracketed by standards.