Solutions and challenges in sample preparation for chromatography.

Sample preparation as practiced today in analytical laboratories is a complex combination of classical and modern techniques. In this review, the progress made in the last few years in sample preparation for chromatography is examined and discussed in comparison with previous achievements in the field. Discovery and development of new materials is seen as one of the main sources of progress, but finding better ways of using the old principles and the improvements in technology are also major contributing factors for advancement. Practical demands for analysis of pharmaceutical products, the environmental studies, and life science are the main driving forces for development in sample preparation for chromatography.

New technique using solid-phase extraction for the analysis of aromatic amines in mainstream cigarette smoke.

A new procedure has been developed for the quantitation of aromatic amines in mainstream cigarette smoke. Two solid-phase extraction (SPE) cleanup steps using different retention mechanisms are required to process the samples. The first step uses a cation-exchange cartridge, followed by a second step that uses a cartridge with a hydrophobic retention character. The aromatic amines eluted from the second SPE cartridge are derivatized with heptafluorobutyric anhydride and analyzed with GC-MS selected ion monitoring in the negative chemical ionization mode. This new method has several advantages over other reported techniques, being sensitive, robust, and easily automated. The detection limits ranged from 0.02 ng/cigarette for tolidine to 1.41 ng/cigarette for aniline and the recoveries were from 79 to 109%.

Analysis of pyridines in mainstream cigarette smoke.

A new technique has been developed for the quantitative analysis of pyridines in mainstream cigarette smoke using a GC-MS technique. For analysis, 10 cigarettes are smoked using conditions based on US Federal Trade Commission recommendations. The smoke is collected in a water trap and analyzed using a GC-MS technique. A standard or a fast GC separation can be applied for the analysis. The standard separation was followed by MS detection using selected ion monitoring (SIM) acquisition on a quadrupole instrument. The fast GC was followed by MS detection with total ion acquisition on a time-of-flight instrument. The levels of pyridine depend on the type of cigarette: for a full flavor cigarette pyridine is as high as 18.0 microg/cigarette (cig.). and for an ultra light cigarette is about 3.0 microg/cig. Substituted pyridines vary between 5.0 microg/cig. to 0.1 microg/cig. for a full flavor cigarette, and between 0.2 microg/cig. and a few ng/cig. for an ultra light cigarette. The reproducibility of the technique is very good, with less than 7-8% RSD in both separation procedures for most of the analyzed compounds.

Analysis of polycyclic aromatic hydrocarbons in the particulate phase of cigarette smoke using a gas chromatographic-high-resolution mass spectrometric technique.

A new procedure is developed for the extraction of polycyclic aromatic hydrocarbons (PAHs) from the particulate phase of cigarette smoke. The procedure applies solid-phase extraction using a Bond Elut CH cartridge as a sample preparation step. The efficiency of the cleanup procedure is verified using a gas chromatographic (GC)-high-resolution mass spectrometric (MS) technique, proving that no interference occurs in the PAHs' determination. The efficient cleanup allows GC detection using either high- or low-resolution MS detection. Enhanced sensitivity is obtained using GC-MS and selected ion monitoring. This new technique has several advantages over other reported techniques. The method is simple and robust and has good repeatability and accuracy. The estimated detection limit is 0.1 ng/cigarette for benzo[a]pyrene. In addition to that, the recovery from the smoke pad in which the smoke is collected is approximately 97% for all PAHs. Results for the PAH analyses for 1R5F, 1R4F, and 1R3 Kentucky reference cigarettes are reported in this study. These results provide useful evidence for clarifying the controversy about previously reported data.

Analysis of polycyclic aromatic hydrocarbons, phenols and aromatic amines in particulate phase cigarette smoke using simultaneous distillation and extraction as a sole sample clean-up step.

Polycyclic aromatic hydrocarbons (PAHs), phenols and aromatic amines can be analyzed in particulate phase mainstream cigarette smoke using simultaneous distillation and extraction (SDE) as a unique sample clean-up step. All analytes are determined from the same smoke sample using GC-MS. The smoke from 20 cigarettes is collected on a Cambridge smoke pad where a mixture of internal standards is added. The Cambridge smoke pad is extracted in a SDE apparatus using water-CH2Cl2. The SDE extract is analyzed directly for PAHs, for phenols after silylation, and for amines after derivatization with heptafluorobutyric anhydride. Excellent results in agreement with data reported in the literature are obtained by this procedure.