The Alpha Cystine is a reference material used to calibrate 2400 Series analyzers. Cystine is a combination of carbon (29.99%), hydrogen (5.03%), nitrogen (11.66%), and sulfur (26.69%). This material comes standard in the CHN/S(O) Standards Kit (02400083) and the CHSN 2000 Runs Kit (N2410684). With this part number, you can purchase this material individually to replenish your supplies.