Abstract: A method that can be used for the monitoring of exposure to alkylating agents in the environment is presented. It is based on the quantification of alkylated N‐terminal valines in hemoglobin, using a modified Edman degradation procedure. The detection limit (GC/electron capture detector or GC/MS) is increased by two magnitudes of ten when using pentafluorophenyl isothiocyanate instead of phenyl isothiocyanate in the derivatization step. As little as one nmole N‐(—2 hydroxyethyl)valine per gram hemoglobin can be detected under practical conditions.

Abstract: Synthetic deoxyoligonucleotides have been 5'-aminoalkylated at the end of step-wise synthesis on the polymer support. This was achieved through the activation of the 5'-hydroxyl group as its 5'-imidazolyl derivative using carbonyldiimidazole, which was subsequently displaced with hexamethylene diamine to yield the title compound. The alkyl carbamate linkage thus generated withstands the deprotection conditions used in oligonucleotide synthesis. Purification by gel electrophoresis and further derivatization at the 5'-amino group with N-hydroxysuccinimidobiotin is described.

Abstract: Globin samples from ethylene oxide-exposed workers and non-exposed referrents were analysed by two methods: (i) gas chromatography-mass spectrometry determination of Nt-(2-hydroxyethyl)histidine as its methyl ester heptafluorobutyryl derivative, after hydrolysis of the protein and isolation of the alkylated amino acid by ion exchange chromatography. The internal standard, Nt-(2-hydroxy-d4-ethyl)histidine, was added to the protein before hydrolysis. (ii) Determination of N-(2-hydroxyethyl)valine after derivatization of the protein by a modified Edman procedure, extraction and g.c.-m.s. determination of alkylated N-terminal valine in the form of its pentafluorophenylthiohydantoin derivative. The internal standard used was in this case a globin with a known content of hydroxy-d4-ethylated amino acids. The two methods gave consistent results, especially at high levels of alkylated products. The average content of hydroxyethylhistidine was 0.6 nmol/g higher than the content of hydroxyethylvaline. Higher levels of background alkylation (of unknown origin) were recorded with the histidine method as compared with the valine method, suggesting that the latter assay should show greater sensitivity for low level ethylene oxide exposure monitoring.

Abstract: 4-Trifluoroacetamidoaniline was reacted with reducing oligosaccharides in the presence of sodium cyanoborohydride to give aminoalditol derivatives, useful for linkage to proteins or solid matrices. A mixture of reducing oligosaccharides, difficult to separate by HPLC, was treated in the same way. The resulting derivatives were easily separated by HPLC.

Abstract: Direct analysis of polar solutes by supercritical fluid chromatography (SFC) has been somewhat limited because the mobile phases in common use are all relatively nonpolar. Derivatization is demonstrated as a viable means for facilitating the SFC separation of sugars. Oligo- and polysaccharides containing up to 18 glucose units are completely resolved by capillary SFC.

Abstract: An HPLC system has been developed in which 23 phenylthiocarbamyl (PTC) amino acids are distinctly separated. Applying this system, the preceding steps in HPLC amino acid analysis i.e. gas-phase hydrolysis of the protein/peptide sample and the pre-column derivatization, were evaluated and optimized. PTC amino acids in HPLC buffer solution are stable for at least 16 hours if stored at 5°–8°C. The sensitivity of the method is in the low pmol range.

Abstract: Two highly sensitive, chiral derivatization reagents, 1-(1-anthryl)- and 1-(2-anthryl)ethylamines, have been developed. Condensation of carboxylic acids with the chiral reagent was effected in the presence of water-soluble carbodiimide and 1-hydroxybenzotriazole. The diastereomeric amides formed from N-acetylamino acid and naproxen enantiomers were efficiently resolved by normal phase chromatography (Resolve 5μ Spherical Silica column) with hexane/ethyl acetate as a mobile phase. With a fluorescence detector (excitation 260 nm, emission 400 nm), the detection limit was 100 fmol (S/N=10).

Abstract: Reliable and sensitive amino acid analyses are important steps in studies of protein structures. In this respect, high performance liquid chromatography (HPLC) has greatly increased speed and sensitivity. The use of ortho-phthalaldehyde [1] and subsequent fluorimetric detection is applicable also to HPLC. Thus, separation of underivatized amino acids by ion exchange HPLC and subsequent detection by post-column derivatization [2], as well as pre-column derivatization and subsequent separation of amino acid derivatives by reverse phase HPLC have been widely used. We have tested both methods and find, like others, that they are suitable. However, base line drift due to ammonia contamination is a serious problem when maximal sensitivity is attempted in the post-column mode of the ortho-phthalaldehyde method. Similarly, the lack of direct detection of proline requires one further step in this derivatization procedure [3] both in the pre- and post-column derivatization mode. Therefore, additional methods for analysis are of value. In this respect, pre-column derivatization with phenylisothiocyanate (PITC) to produce the phenylthiocarbamyl (PTC)-amino acids for subsequent separation by reverse phase HPLC has proved highly efficient and valuable [4, 5]. We have tested this method extensively and find it reliable, sensitive, and easy to use.

Abstract: The application of a technique for the determination of aflatoxins by reverse phase HPLC and fluorescence detection incorporating post-column derivatization with iodine, is described. The procedure proved to be extremely sensitive and reproducible. Chromatograms of extracts from maize, peanut butter, sorghum malt and duckling mash are presented illustrating the value of the procedure for confirming the presence of aflatoxins B1 and G1.