Chromatography of Dns derivatives on pre-coated high-performance thin-layer chromatographic plates

Determination of biogenic amines by capillary electrophoresis with pulsed amperometric detection

The biogenic amines, putrescine, cadaverine, spermidine and spermine were separated and quantified by capillary electrophoresis with pulsed amperometric detection. Detection potential of the pulsed amperometric detection was optimized as 0.6 V. Optimal separation of the biogenic amines was achieved using a separation buffer of 30 mM citrate at pH 3.5, while keeping the buffer in the detection cell as 20 mM NaOH. Using these conditions, the four biogenic amines were baseline separated. Extrapolated limits of detection for putrescine, cadaverine, spermidine and spermine were 400, 200, 100 and 400 nM for the standard mixture (polyamines dissolved in running buffer), respectively. These are lower than ultraviolet detection and comparable or even lower than laser-induced fluorescence detection results as reported in the literature. The number of theoretical plates was maintained at the 10(5) level, which is absolutely higher than any reported method. When applying capillary electrophoresis-pulsed amperometric detection to milk analysis, only spermidine was found in amounts varying between 0.1 and 0.5 mg/kg.

Polyamines as cancer markers: applicable separation methods

Spermine, spermidine, putrescine and cadaverine are aliphatic amines widely spread in the human body. Their concentrations together with their acetyl conjugates increase significantly in the biological fluids and the affected tissues of cancer patients. Their concentrations decrease with the improvement in the patient's condition on multiple therapy. Various chromatographic techniques are frequently used in monitoring concentrations of di- and polyamines in cancer. Among these techniques, thin-layer chromatography and liquid chromatography using pre- or postcolumn derivatization, separating on a reversed-phase or an ion-exchange column are the most commonly used. Besides, high-resolution capillary column gas chromatography (GC) is increasingly used over packed column GC, and in recent years, capillary zone electrophoresis has also gained some importance in polyamine determinations. The review examines the prospects and the limitations of polyamines as cancer markers using chromatographic and electrophoretic techniques.

Thin layer chromatography of dansyl and dinitrophenyl derivatives of amino acids. A review

The dinitrophenyl (DNP) derivatives of amino acids have found continual application in protein sequencing since Sanger used them for the first time for the sequencing of insulin. Dansyl derivatives of amino acids have been widely used in protein sequencing because of their fluorescent nature. The success of protein sequencing largely depends upon correct identification of such derivatives. The choice for the method of identification is related to cost, the availability of instrumentation and to the sensitivity needed for the analysis. Thin layer chromatography (TLC) is simple and has several advantages over other chromatographic methods. Therefore the literature after 1972 is reviewed for TLC analysis of dansyl- and DNP-amino acids, the two important amino acid derivatives required for identifying protein sequences. Additionally, the literature on the TLC resolution of enantiomeric mixtures of dansyl amino acids is reviewed. Application of various adsorbents, composition of solvent systems and other experimental conditions together with successful resolution data have been discussed. TLC provides a direct and inexpensive method for the resolution of enantiomers, and is fast becoming a sensitive instrumentalized quantitative analytical technique.

Polyamines

Putrescine, spermidine, spermine and their derivatives are considered to be potential markers of certain diseases. Routine methods have, therefore, been developed in the course of the last decade. Several automated liquid chromatographic and gas chromatographic methods are presently at our disposal, which meet the practical requirements of sensitivity and specificity. They make the routine application of gas chromatographic-mass spectrometric methods dispensable. Very recently the amino acids deriving from polyamines have also been taken into consideration as tumour markers. Their separation by capillary gas chromatography has been reported. Separation of ion pairs on reversed-phase columns may also prove useful in the establishment of complete concentration profiles of polyamines and their derivatives in tissues and body fluids.

The determination of N1-acetylspermine in mouse liver

N1-Acetylspermine has been postulated to be an intermediate in the conversion of spermine to spermidine. This compound, together with N1-acetylspermidine has now been detected in the liver of mice which were pretreated with tetrachloromethane. The following methods were used for the identification of N1-acetylspermine: (a) High-pressure liquid-chromatography of the non-derivatized amines on a reversed-phase column, using octane sulfonate for ion-pairing. (b) Thin-layer chromatography of the dansyl derivatives. (c) Mass spectrometry of the dansyl derivatives. Both chromatographic methods allowed the quantitative estimation of N1-acetylspermine and N1-acetylspermidine in the liver of tetrachloromethane-treated animals.

A microliter method for the gas chromatographic determination of long-chain non-esterified fatty acids in human serum or plasma

Non-esterified fatty acids (NEFA) from C12 to C24 are assayed in human serum or plasma in a four-step procedure: extraction, volume reduction, methylation and gas chromatography. NEFA are extracted with chloroform--heptane--methanol from 50--100 microliter of serum or plasma buffered with phosphate. After adding ethyl acetate the volume of the extract is reduced under partial reflux to 5--7 microliter. Potassium carbonate, methyl iodide and a crown ether are added to the dry concentrate and the NEFA are selectively methylated with a yield of 100% by heating in a microrefluxer for 10 min. Gas chromatography is carried out with 1 microliter of the reaction mixture on a packed column by temperature-programmed operation. Thirteen individual fatty acids are determined in sera of normal adults. The coefficients of variation for 24 determinations of a pooled serum were 2.7% for the total NEFA content and 3--10% for most of the individual NEFA.

Determination of di-and polyamines by high-performance liquid chromatographic separation of their 5-dimethylaminonaphthalene-1-sulfonyl derivatives

Using a Lichrosorb RP-8 reversed-phase column and a methanol--water gradient elution program, it is possible to separate within 40 min and to determine routinely in picomole quantities the natural di- and polyamines. The precision of the method is comparable to the thin-layer chromatographic procedures, the separations are most efficient, and the method can be fully automated. A modified gradient enables the repeated assay of spermidine and spermine within 20 min. The method is suited for polyamine analyses in tissues and body fluids.

Chromatography of biogenic amines. I. Generally applicable separation and detection methods

This first part of the review on "Chromatography of Biogenic Amines" is devoted to the description of generally applicable separation and detection methods. Gas chromatographic and gas chromatographic-mass spectrometric methods, and applications of chromatographic methods to specific amines or groups of related amines and their metabolites, will be covered in Part II. Trends in the development of separation methods (paper and thin-layer chromatography, paper and thin-layer electrophoresis and ion-exchange methods) are described, using mostly aliphatic amines as examples as they do not exhibit features that permit their specific determination. Reagents suggested for the formation of coloured and fluorescent derivatives of amines are reviewed and their applications are described. Within the limitation of the reviewed and their applications are described. Within the limitation of the mostly inadequate information that is available, the relative usefulness of the different derivative-forming reactions are compared.