An in situ synthesis of cyanogen chloride as a safe and economical aqueous standard

This study developed the in situ synthesis of CNCl as a safe and economical aqueous standard, based on Standard Method 4500-CN− E. This study demonstrated that the synthesized CNCl standards are comparable with commercial standards based on results from purge-and-trap GC/MS analysis and micro-liquid/liquid extraction with GC/ECD analysis. Furthermore, the synthesized CNCl solution provides a source of externally prepared standards, which avoids gas–liquid transfer procedures. Only microgram quantities of this hazardous substance were generated and may be safely converted to the relatively innocuous cyanate ion immediately after use by simply raising the pH. This performance-based approach led to a successful means to synthesize aqueous CNCl solutions as either quality control standards or calibration standards. It may be especially useful for laboratories in other countries where CNCl is difficult to acquire.