Recently, the progress of mass spectrometry has been mainly achieved with the development of new soft ionization techniques, such as secondary ion mass spectrometry, plasma desorption, fast atom bombardment, laser desorption, multiphoton ionization, and so on, and with the development of chromatography/mass spectrometry such as gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry and so on. It has been demonstrated that nonvolatile large molecules can be ionized by these soft ionization methods, which are reviewed. The combination techniques of gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry are very powerful methods for mixture analysis and are applied to various fields. These are also reviewed here.
New NMR techniques have proliferated during the past 10 years. In the techniques, two dimensional NMR has been used as routin technique for structure analysis of unknown compounds. High resolution NMR of solid become familiar and give the information of the structure and morphology of solid materials. NMR imaging has been rapidly developed and applied to new medical application field. This article will introduce outline of the technical situation and some applications for each item, and discuss about future prospects of NMR.
Recent advances in theoretical and practical aspects of the application of fluorescence cytophotometry to biological specimens were described. A new method of quantitative detection of DNA damage by computer analysis of Feulgen hydrolysis curve was introduced. The rate constans of depurination and depolymerization in Feulgen hydrolysis can be expressed in the form of k=AN2·exp (-E/RT), where A is a constant, N is HCl concentration, E is the activation energy, R is the gas constant, and T is the absolute temperature. And the Feulgen hydrolysis curve is determined by y (t) =y0k1/ (k2-k1) · (ek1t-ek2t), where y (t) is the amount of apurinic acid stainable with Feulgen reaction at hydrolysis time t, y0 is the amount of apurinic acid theoretically present at t=0. Computer fitting of Feulgen hydrolysis curve to these function makes it possible to determine the values of y0, k1, k2, and E. 1/k1 correlates with the degree of chromatin condensation, k2 reflects the degree of DNA instability, and y0 corresponds to the yield of single-stranded DNA induced by DNA damage due to aging, chemical carcinogen, radiation etc. The values of y0 and k2 are larger for the nuclear DNA in cancerous cells than in noncancerous cells. The increased DNA instability in cancerous cells made it possible to differentially stain cancerous cells with acridine orange after acid hydrolysis. This new technique is a useful tool for detecting malignancy in exfoliative cytology and malignant transformation by chemical carcinogen treatment. Some applications of fluorescence cytophotometry on viable cells were also described.
In vivo NMR is a rapidly developing method to analyze the metabolism in living systems. Biochemical information obtained from the analysis of NMR spectra is described, then the advantages and limitations of the method are discussed. Among the wide range of application of in vivo NMR selected examples are shown. Topics are spectral editing, utilization of stable isotopes and magnetization transfer, localized spectroscopy, and newly available nuclei.
A gas-phase protein sequencer which has been developed for last several years allows the determination of N-terminal amino acid sequence of 2030 residues from picomole amounts of proteins. Recently, using the gas-phase sequencer, a new technique for protein microsequence analysis has been established. In this method, picomole amounts of proteins are first separated by gel electrophoresis, then electroblotted from the gel onto sequencer stable membrane supports, and finally sequenced directly with the gas-phase sequencer. This method frequently permits sequence determination of proteins that could not be easily purified by conventional column chromatographies. In this review, the new instrument and technique for protein microsequence analysis are described.
A chemiluminescence-high performance liquid chromatography (CL-HPLC) was developed [T. Miyazawa et al., Anal. Lett., 20, 915, (1987)] for pmol level micro-determination of lipid hydroperoxides present in biological samples such as human blood plasma, and its lipoprotein fractions, tissue organs of experimental animals, and cultured human fetal diploid cells [T. Miyazawa et al., Anal. Lett., 21, 1033, (1988); J. Biochem., 103, 744, (1988)]. The method involves separation of each lipid class from tissue total lipids with normal phase or reversed phase HPLC and post-column detection of hydroperoxide-dependent chemiluminescence that is generated by luminol oxidation during a reaction of lipid hydroperoxides with cytochrome c-heme. The high specificity for their hydroperoxide group enables an assay for a large range of hydroperoxide concentrations, with a detection limit of 10 pmol of phospholipid hydroperoxides, triglyceride hydroperoxides and tocopherol hydroperoxides, respectively.
Recent developments of the instrumental analysis of oligosaccharides were reviewed. The methods involved (1) microanalysis of oligosaccharides by HPLC, (2) sequence analysis by a combination of exoglycosidase and HPLC, and (3) structural characterization by 1H-NMR.
Diarrhetic shellfish poisoning is a gastro-enteritis caused by eating shellfish infested with polyether toxins of dinoflagellate origins. Three structurally different groups of toxins consisting of eight components have been isolated and their structures were determined. The first group comprising okadaic acid and its derivatives are polyether compounds carboxylic acids having strong diarrheagenisity. The second is a pectenotoxin group which shares a polyether macrolide skeleton. The third group is the newest constituent, yessotoxin, which consists of transfusing ether rings, mimicing the structure of brevetoxins.
Bioactive compounds from plants are divided into several groups, but analysis of plant hormones is focused in this paper. Until now 6 kinds of hormones are isolated from plants, namely indole acetic acid (IAA), gibberellins (GA), abscisic acid (ABA), cytokinins, brassinosteroids and ethylene. They are extracted from plants with organic solvents and purified by high performance liquid chromatography (HPLC). Most common column used for HPLC is a reversed phase column such as ODS. Plant hormones are usually delivetized and analyzed by gas chromatography (GC) or combined gas chromatography mass spectrometry (GC-MS). By using methyl silicone (OV-1) capillary column, most of plants hormones are separated effectively. The accurate quantification of plant hormones are performed by GC-MS using stable isotope labeled internal standards. Examples of analysis of hormones are mentioned.
GC/MS of steroids, bile acids, prostanoids, fatty acids, mono- and oligosaccharides, and amino acids and oligopeptides are reviewed with 60 references. Derivatization of hydroxyl groups and carbonyl groups of steroids, prostanoids, and carbohydrate for GC/MS are mainly described.
Recently, much attention has been focused on natural antioxidants from a food safety viewpoints, and we started our new project to isolate a new type of antioxidants from natural resources, in particular, from plant materials. This attempt was mainly with the assumption that endogenous antioxidative components may play an important role for protection from oxidative damage in plants, and may be a good source for natural antioxidants. From these background, the isolation and structure elucidation of antioxidants have been carried out from plant leaf waxes, and two antioxidative β-diketones were found in the leaf wax of E. globulus and three tocopherol dimers and two tocopherol conjugates were isolated from Prunus leaf waxes. Novel lignan type of antioxidants were also isolated from sesame seeds and antioxidative tannins were isolated and identified from herbs and crude drugs. This paper summarizes isolation and analysis of antioxidative components by HPLC and structural elucidation by instrumental analyses such as MS and NMR.
Although most of fresh raw fishes have very faint odor, their “fishy odor” become stronger during storage through the microbial action and the autoxidation of lipids. On the other hand, an appetizing odor is formed when raw fishes are roasted, boiled or fermented. These uncomfortable fishy and pleasant cooked odor have been analyzed in detail using advanced analytical instruments and some important flavor compounds in very small quantities have been identified. This review deals mainly with analytical methods of flavor compounds of raw and processed fishes and the characteristic flavor compounds of fresh raw fishes, stored raw fishes and processed marine products. Furthermore, this review refers to off-flavors of some kinds of raw fish.
It has been known that plant flavor contributes to the food life from old times. For example, some kind of spice has not only added a relish to a dish, but also been utilized for food preservation because of having anti-microbial activity. In general, since flavor components are very volatile and trace amounts, an efficient technique to isolate and identify them is demanded. This review deals with the ultra-microanalysis and physiological effects of plant flavor components, e.g. antithrombotic agents, vinyldithiins in Allium victorialis L., etc.
Amino-carbonyl reaction has extensively occurred in food and biological systems. Low-molecular weight compounds formed by the amino-carbonyl reaction of carbonyl compounds-amino acids or amines have been identified as amides, furans, pyrroles, pyridines, pyrazines and so on. Especially, pyrrole-carbaldehydes were major products of Maillard reaction. Melanoidins formed as final products of Maillard reaction were analyzed by 13C or 15N CP-MAS NMR. The nitrogen atoms of melanoidins were mostly assigned to pyrrole-like, conjugated enamine and amide nitrogens. Amino groups of proteins in biological system as well as food system react non-enzymatically with reducing sugars to form a Schiff base and Amadori compounds in an early stage. In an advanced stage of Maillard reaction, proteins such as collagen and lens crystallin are modified into colored, fluorescent and cross-linked molecules. These processes have been hypothesized to have an important role in the aging and the diabetic complications.
Chlorophylls (Chls) are contained in all photosynthetic organisms ranging from higher plants to algae and some bacteria, and constitute a group of the most abundant metal complexes in nature. Higher plants possess two major Chl derivatives, Chl a and Chl b, whose separation by Tswett at the beginning of this century was the cradle of chromatography. Once extracted from living tissues, Chls are extremely susceptible to molecular alterations including pheophytinization (Mg release), epimerization, ester hydrolysis, and allomerization. This feature often raises serious problems in practical fields such as quality control of processed vegetables, human photo-hypersensitivity, and biosphere activity evaluation. In view of this, a number of methods have been proposed over the past decades for reliable determination of Chl derivatives. This article reviews recent developments and improvements with regard to extraction, separation, and quantitation of these natural pigments. In addition, a brief discussion is given on the requirement for analytical means with enough sensitivity and resolution in the molecular-level elucidation of photosynthetic mechanisms.
Drugs are metabolized in liver and/or target organs mainly. However the metabolizing enzyme activity is variable in individuals because of genetical deviations, aging, environmental factors and so on. Monitoring of drug levels in biological fluids is, therefore, neaded to avoid side effects and hyper responses. Recently, elegant methods, immunoassay based upon the antigen-antibody reaction and high-performance liquid chromatography (HPLC), have been introduced into the clinical field. In this review we describe the basics and applications for drug level monitoring of these methods. Gas chromatography is also discussed briefly.
The living organism is a dynamic steady-state system in the delicate shifts and balances. This homeostatic mechanism implies that all the necessary enzyme-catalyzed reactions proceed at rates responsive to changes in the internal and external environment, with hormonal and neural control. The living organism might be defined as diseased when it responds inadequately or incorrectly to an internal or external stress. The causes of diseases are the factors affecting the rate of enzyme-catalyzed reactions. Diagnosis of disease depends especially on the accuracy of analytical methods. DNA probe assay, enzymatic analysis, immunoassay, receptor assay, neutral carrier membrane assay, atomic spectrochemical analysis, magnetic resonance spectroscopy, and mass spectroscopy are useful.
A trace element taken in a living body acts as an essential or toxic substance for the life preservation according to the amount of their physiological demand. It is also expected that the activity of trace elements in a living body suffers from coexisting substances, resulting in the so-called reciprocal and/or competitive effect. From these reasons, the development and the practice of simultaneous multielement analysis are required intensely in many fields of environmental science such as analytical chemistry, biology, agriculture, nutrition, medicine etc. In this paper, the following methods used in recent papers are reviewed as simultaneous multielement analysis : neutron activation analysis (instrumental- and radiochemical-; INAA and RNAA), particle induced X-ray emission spectrometry (PIXE), X-ray fluorescence spectrometry (XFS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and simultaneous multielement atomic absorption spectrometry with continuum source (SIMAAC).