HS-SPME Determination of Volatile Carbonyl and Carboxylic Compounds in Different Matrices

Abstract

Specific chromatographic methodologies are developed for the analysis of carboxylic acids (C(2)-C(6), benzoic) and aldehydes (C(2)-C(10)) of low molecular weight in diverse matrices, such as air, automotive exhaust gases, human breath, and aqueous matrices. For carboxylic acids, the method is based on their reaction with pentafluorobenzyl bromide in aqueous solution, followed by the separation and identification of the resultant pentafluorobenzyl esters by means of headspace (HS)-solid-phase microextraction (SPME) combined with gas chromatography (GC) and electron capture detection (ECD). Detection limits in the microg/m(3) range are reached, with relative standard deviation (RSD) less than 10% and linear response (R(2) > 0.99) over two orders of magnitude. The analytical methodology for aldehydes is based on SPME with simultaneous derivatization of the analytes on the fiber, by reaction with pentafluorophenylhydrazine. The derivatization reagent is previously deposited on the SPME fiber, which is then exposed to the gaseous matrix or the HS of the sample solution. The pentafluorophenyl hydrazones formed on the fiber are analyzed selectively by means of GC-ECD, with detection limits in the ng/m(3) range, RSD less than 10%, and linear response (R(2) > 0.99) over two orders of magnitude.

Determination of aldehydes in human breath by on-fibre derivatization, solid-phase microextraction and GC–MS

“…The maximum response was obtained with the PDMS/DVB coated fibre, which had previously been reported as being suitable for aldehyde analysis [24,27].…”

“…Clearly, there is Typical concentrations of potential biomarkers in exhalation samples are in the nanomolar range, therefore pre-concentration techniques, such as automatic thermal desorption with sorbents and cryofocusing, are required [12]. Another recently developed technique with considerable potential for preconcentrating volatile analytes is 'solid-phase microextraction' (SPME) [21][22][23][24]. SPME, coupled to GC-MS, has been used to quantify levels of VOCs [22], acetone [21,25] and isoprene [21,26] in exhaled breath.…”

Sampling flower scent for chromatographic analysis

“…In vivo HS-SPME/GC-MS analysis of flower volatiles was performed with the fiber (PDMS, 100 lm) previously saturated with pentafluorophenylhydrazine (PFPH), used as an aldehyde and ketone derivatizing agent [87], in order to selectively detect some volatile aliphatic aldehydes [88], present as traces in the B. suaveolens flower scent (barely detected by HS-SPME with mass spectrometric or flame ionization detection). The determination of aldehydes and ketones, as PFPH-derivatives, was performed by capillary GC with electron capture detection (ECD), as described elsewhere [89].…”

Quantification of benzene, toluene, ethylbenzene and o-xylene in internal combustion engine exhaust with time-weighted average solid phase microextraction and gas chromatography mass spectrometry

“…A number of methods have been developed for determination of VOCs concentrations in exhaust gases. The most popular are gas chromatographic methods with different types of sample preparation (dynamic sampling via pumping exhaust through tubes with different types of sorbents [9]), direct sampling with a syringe injection [10], whole air sampling with Tedlar bags [11] and evacuated canisters [12,13], and solid phase microextraction (SPME) (with exposed fiber) [14]) and detection with mass spectrometric (MS) [15], flame-ionization (FID) [16], infrared [17] methods. These methods often require specialized equipment and interface (e.g., to extract and clean evacuated canisters; pumps, sorbent tubes and thermal desorption) that is cost-prohibitive to many potential users to maintain and to work with.…”