Determination of carbonyls using liquid chromatography-mass spectrometry with atmospheric pressure chemical ionization

Abstract

A liquid chromatographic method for the determination of aldehydes and ketones based on mass spectrometric detection is described. Recently developed modular derivatizing agents are employed for analysis. These hydrazine reagents, e.g. 4-dimethylamino-6-(4-methoxy-1-naphthyl)-1,3,5-triazine-2-hydrazine (DMNTH), react with the carbonyl compounds with the formation of the respective hydrazones, which are separated by HPLC-MS with atmospheric pressure chemical ionization in the positive mode. Electrospray ionization may also be used for analysis. Particular focus is directed on various calibration approaches, including external calibration with standard solutions and internal calibration with a hydrazone standard of cyclobutanone, an aldehyde not likely to occur in real samples. A second approach for internal calibration is based on the 13C2-labelled acetaldehyde hydrazone standard. Different calibration approaches may then be used for the analysis of real samples. Limits of detection range from 2 x 10(-8) to 5 x 10(-8) mol L-1 for a series of hydrazones, including hydrazones of saturated aldehydes with alkyl chain lengths from 1 to 7 carbon atoms, and hydrazones of selected unsaturated and aromatic aldehydes as well as ketone hydrazones.

Air monitoring of aldehydes by use of hydrazine reagents with a triazine backbone

“…Their structures are depicted in Scheme 1. These reagents not only fluoresce strongly, they can also be used in conjunction with massspectrometric detection, because they are readily ionized by electrospray ionization (ESI) or atmospheric-pressure chemical ionization (APCI) in the positive-ion mode [15]. Because of its rapid reaction with aldehydes and ketones, DMNTH has been successfully used for the determination of carbonyl compounds in water [16].…”

“…A chromophoric or fluorophoric group, a reactive moiety, and a third functionality, e.g. to modify the polarity of the complete reagent in the desired way, are coupled to cyanuric chloride by means of nucleophilic substitutions or Friedel-Crafts alkylations [14,15,16]. 4-N,N-Dimethylamino-6-(4′-methoxy-1′-naphthyl)-1,3,5-triazine-2-hydrazine (DMNTH), and Nmethyl-4-N′,N′-dimethylamino-6-(4′-methoxy-1′-naphthyl)-1,3,5-triazine-2-hydrazine (MDMNTH) have been identified as being particularly favourable.…”

Atmospheric pressure chemical ionization mass spectrometry of aldehydes in biological matrices

“…17 As is now common in recent analytical developments, GC is frequently substituted by HPLC analysis. [9][10][11]15,16,24 In these studies, DNPH derivatives were found most useful. Single-stage mass spectrometry is more specific than UV, and detection limits may reach the lowpicogram range.…”

“…The most common method is derivatization with 2,4-dinitrophenylhydrazine (DNPH) reagent. 15 Alternatives include derivatization with 4-dimethylamino-6-(4-methoxy-1-naphthyl)-1,3,5-triazine-2-hydrazine, 16 and the use of pentafluorophenyl-, 2-chloro-and 2,4-dichlorophenylhydrazine derivatives. 17,18 Analysis is often performed using gas chromatography (GC), [18][19][20] with flame ionization (FID), 19 occasionally with mass spectrometric 2,21 or ECD 17,18 detection.…”

The use of hydrazine-based derivatization reagents for improved sensitivity and detection of carbonyl containing compounds using MALDI-MSI

“…There are several reports on the use of DMNTH as a derivatization reagent. Examples are the derivatization of carbonyl containing compounds followed by chromatographic separation and detection by atmospheric pressure chemical ionisation (APCI) mass spectrometry and in water samples [10,11]. The optimised parameters necessary for the separation of DMNTH derivatized carbonyl compounds by reversed phase capillary electrochromatography (CEC) have been described [12].…”