J. Itoh

APPLICATION OF A POWDERED-INTERNAL-STANDARD METHOD TO PLANT AND SEAWEED SAMPLES

A preparation method making use of liquid nitrogen combined with a powdered-internal-standard method has been established for seaweed and plant samples, whose elemental concentration has been attracting attention in various research fields. It is found that a powdered-internal-standard method developed by us is applicable to the powdered samples treated with liquid nitrogen with good accuracy and reproducibility. The results were compared with those obtained by direct-powder method and by chemical-ashing method and good agreement was obtained. In addition, it is found that the whole sample of large quantities was almost uniformized by this preparation method. Moreover, it becomes possible to obtain concentrations of all the concerned elements including iodine, chlorine and bromine, which are essential elements in the fields of life-sciences and are difficult to be analyzed by the chemical-ashing method. It is expected that the application to other biological samples is also promising.

ELEMENTAL ANALYSIS OF VEGETABLES ON THE MARKET — Comparison with Wild Plants

We have measured concentration of multi elements in vegetables on the market and a wild plant gathered around Nishina Memorial Cyclotron Center in Iwate prefecture by means of PIXE. Elemental concentration in vegetables cultivated by spraying mineral-rich waters was also analyzed. As a result, it is found that the mineral-supplying vegetables abundantly contain essential elements for body such as K, Ca, Fe, Cu and Zn in comparison with ordinary ones. With regard to a wild plant, concentration of essential elements such as Ca, Cu and Zn shows no clear difference in comparison with that in commercially available one of the same kind, while that of toxic elements such as Cr and Pb is relatively higher. Moreover, it is suggested that the wild plant has a certain property of concentrating a specific element depending on its growing period. The relation between elemental concentration in the plants and that in their growing environment, such as water and soil, was also examined. It is also suggested that elemental concentration in vegetables reflects elemental constituent not only of the soil but also of the sprayed water as well as of the fertilizer.

SIMULTANEOUS MEASUREMENT OF TWO DIFFERENT TARGETS BY MEANS OF VACUUM AND IN-AIR PIXE

A simultaneous measuring system of two different targets by in-vacuum and in-air PIXE has been developed in order to improve efficiency of analyses in the limited machine time. The proton beam passes through a thin target in vacuum and it allows us to perform in-vacuum PIXE, and the beam is further transported to the in-air PIXE system for analyzing another target. The beam intensity for in-air PIXE while performing in-vacuum PIXE is 1.5 nA, which is almost sufficient. The effect of slight changes in the beam transport parameters on the background X-rays for both in-vacuum and in-air PIXE has been found to be negligible. As a result, it is confirmed that accuracy and sensitivity of analysis for many kinds of sample, such as various samples in earth, environmental sciences and in bio-medicine, are almost unchanged for the both systems, and a four-detector-simultaneous measuring system has been completed. It is expected that the system will work miracle for solving the problem of deficient machine time in our laboratory.

PHYSICAL QUANTITATIVE ANALYSIS IN IN-AIR PIXE

A physical method of quantitative analysis for in-air PIXE has been established. Among the three parameters required for performing physical analysis, X-ray production cross sections were recalculated by using the effective energy of the proton beam after losing its energy through a Kapton foil and in air. Detection efficiencies of the Si(Li) detector have been determined according to our method established for in vacuum system, where effects of absorption of X-rays in air are incorporated into the detection efficiencies. As a result, it is confirmed that the present method gives us accurate results in the analyses of standard samples as well as actual samples such as soil and ash. It becomes possible to perform quantitative analysis of various samples by optimizing the measuring conditions depending on the samples.

FLUORINE AND MULTI-ELEMENT ANALYSIS OF MUSHROOM SAMPLES BY MEANS OF PIXE SYSTEM

We have measured concentration of multi elements including fluorine in mushrooms collected in Iwate prefecture, Japan. As a result, it was confirmed that the sample preparation method, which was established for the plant samples, is applicable to the mushroom samples and the elemental concentration was obtained in good accuracy and reproducibility. Moreover, it becomes clear that the mushroom takes a specific element selectively depending on its species, and it is found that to analyze various kinds of mushrooms is of great use as a way of monitoring environmental pollution. Fluorine concentration is found to be 7-68 ppm in the mushroom samples. However, clear correlation of fluorine and other elements was not observed in each sample in this study.

STANDARD-FREE METHOD FOR BODY FLUID SAMPLES SUCH AS SALIVA, SWEAT, SNIVAL AND TEAR

We have developed standard-free methods for PIXE analysis of hair, nail, urine and serum, and they have widely been applied to studies on human exposure to some toxic elements caused by pollution in many countries. Although these samples are known to be quite suited for evaluating human exposure to toxic elements, there is a case where it is required to quantitatively analyze other samples taken from people. We have examined sweat, saliva, snivel and tear, which are expected to be useful for estimating concentration of various elements in a human body. However, sufficient quantities of them are difficult to be taken from a human body and it is required to establish standard-free methods for these samples. In the present work, standard-free methods for sweat and saliva were established and its accuracy and reproducibility are confirmed. It becomes possible to quantitatively analyze only a drop of sweat and saliva by means of this method. For snivel and tear, potassium concentration is obtained by the inter...

QUANTITATIVE ANALYSIS OF VERY SMALL QUANTITY OF ORGANS TAKEN FROM PATIENTS AND EXPERIMENTAL ANIMALS: STANDARD-FREE METHOD FOR ORGAN SAMPLES

A standard-free method for small lymph node and spleen samples taken from rats, and lymph node, esophagus, colon etc. taken from real patients has been developed in order to take measure to meet increasing demands for quantitative analyses of small amount of organs. It becomes possible to quantitatively analyze organ samples of less than 1 mg collected from small experimental animals and also from patients by biopsy, and accuracy and sensitivity of the method were examined by comparing the results with those obtained by a powdered-internal-standard method and a chemical-ashing method. It is found that the method is quite effective for estimating therapeutic effect of CDDP (Cisplatin) since it allows us to quantitatively evaluate uptake of CDDP into organs by analyzing small quantity of samples taken from actual patients by biopsy. It is expected that the method will become a powerful tool for studies not only in fundamental and clinical medicines but also on practical diagnosis and treatment.

Elemental concentration in the hair taken from healthy people for the past 20 years — 1. Long-term changes over 20 years

We developed a standard-free method for untreated hairs and the method has been applied to quantitative analysis of more than 30,000 hairs taken from the people concerned in order to evaluate exposure to some toxic elements and intakes of essential elements. Besides these analyses, we have measured nearly 2000 hairs collected from healthy people in Japan over the past 20 years. It was found that concentrations of some elements, such as vanadium, chromium, manganese, copper and mercury, keep increasing up to the present. Such tendencies were particularly notable for female, while not clearly observed for male. Concentrations of some essential elements, such as calcium, magnesium and zinc, show no obvious long-term variations. On the other hand, iron and selenium show slightly decreasing tendencies. With regard to toxic elements, it was found that arsenic, chromium and mercury are tending to increase year by year.

ELEMENTAL ANALYSIS OF EDIBLE PLANTS IN NATURAL ENVIRONMENT: Trace Elements in Wild Plants

We have measured concentration of multi elements in wild plants collected in Iwate prefecture, Japan. It is found that wild plants contain essential elements such as iron, copper and zinc in the same degree or more in comparison with those in vegetables on the market. It is also found that wild plants contain toxic elements such as chromium and lead in the same degree or less in comparison with vegetables on the market. We took the soils together with the wild plants in nine representative spots and analyzed elemental concentration in them in order to examine the relationship of elemental concentration between plants and soils. Although elemental concentration in each soil has distinguished features, which in wild plants grown on the soil does not directly reflect that in the soil. It is expected that elemental concentration in wild plants is influenced by various factors such as chemical state of existing elements in the soil, pH of the soil, activity of microorganism in the soil, and many other factors.

STANDARD-FREE METHOD FOR BEARD SAMPLES OF VERY SMALL QUANTITY

We developed and reported standard-free methods for various samples such as hair, nail, urine, serum, sweat, snivel, tear and saliva, and they have been confirmed to be effective for addressing global environmental issues. It is expected that analyses of beard samples give us useful information about daily changes of elemental concentration in the body in comparison with the other samples. In this work, a quantitative method for untreated beard analysis based on the standard-free method has been developed. By means of the method, it becomes possible to quantitatively analyze extremely small quantity of beard samples, which are daily taken with ordinary electric shaver. The optimum conditions of washing samples have also been examined. It is found that some elements such as potassium, calcium and chlorine are lost by washing in distilled water and it is better to wash the sample in acetone. As a result, the standard-free method for beard samples has been successfully established and good accuracy and reproducibility were achieved.