Separation of 17 DNPH derivatised carbonyles

Carbonyl compounds are often found in urban atmospheres and can give rise to photo-chemical smog and reactions leading to ozone formation. The main source of these compounds includes products of incomplete hydrocarbon combustion produced by internal combustion engines. Insulating materials used in buildings and furniture can also be a source of such compounds in the atmosphere.

Introduction

This application note gives an HPLC method for the separation and detection of carbonyl compounds in aqueous samples. Extracts are first derivatised with 2,4 dinitrophenylhydrazine (DNPH). After derivatisation, the carbonyl compounds are extracted and injected onto a Merck Hibar® HR 100-2.1 mm Purosher® STAR RP-18e, 2 μm column and separated using gradient elution. The separated compounds are then quantified by UV detection at a set wavelength of at 360 nm. These analytical procedures are consistent with U.S. EPA Method 554, pertaining to drinking water samples and U.S. EPA Method 8315, pertaining to aqueous and solid waste, soil, stack gas and indoor air samples. In this method the VWR Hitachi Chromaster is used in a mixerless pump formation, meaning that the system delay volume is kept to a minimum. The high performance Chromaster proportioning valve is used in a high frequency mixing mode (HFM) instead of a mixer. This use of Hitachi‘s expertise in high performance electronics has greatly improved the design of low pressure gradient (LPG) accessories, meaning that in a number of applications a high pressure gradient binary system is not necessary. This makes use of the flexibility of a LPG quaternary system where by tetra hydrofuran is used as a third component of the mobile phase. The THF aids the separation of the more polar components by forming an intermediate complex to slightly reduce the polarity of these derivitised compounds. 

Large quantities of carbonyl compounds are used worldwide as raw materials and intermediates in the chemical and plastics manufacturing industries. These compounds are skin, eye and respiratory system irritants, many are also suspected of being carcinogenic. Owing to widespread, high volume industrial use of such compounds, they are present in workplace air spaces and industrial waste materials. As a result of this they are also present in municipal waste burial sites, which can contaminate groundwater that may eventually be used for drinking.