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A new analytical methodology for a simple and efficient on-line preconcentration of trace inorganic anions in water and salt samples prior to ion chromatographic determination is proposed. The preconcentration method is based on partition/ion-exclusion chromatographic ion stacking (PIEC ion stacking) with a hydrophilic polymer gel column containing a small amount of fixed anionic charges. The developed on-line PIEC ion stacking-ion chromatography method was validated by recovery experiments for the determination of nitrate in tap water in terms of both accuracy and precision, and the results showed the reliability of the method. The method proposed was also successfully applied to the determination of trace impurity nitrite and nitrate in reagent-grade salts of sodium sulfate. A low background level can be achieved since pure water is used as the eluant for the PIEC ion stacking. It is possible to reach sensitive detection at sub-μg L-1 levels by on-line PIEC ion stacking-ion chromatography.

Contents 2-3Chapter 1 4-18General Introduction1.1 Preface1.2 The Background/Origin of the present research1.3 Effect of electrolytes in the distribution process1.4 Goal of this study1.5 Summary of the thesis1.6 References Chapter 2 19-26Theoretical2.1 References Chapter 3 27-50Ion stacking mechanism on C18 silica and hydroxyl polymethacrylate gels3.1 Introduction3.2 Experimental3.2.1 Chemicals3.2.2 Instrumentation and Chromatographic Procedure3.2.3 Determination of cation-exchange capacity of a TSKgel G2500PWXL column3.3 Results and Discussion3.3.1 Stacking behavior of inorganic anions on a C18 silica column3.3.2 Ion stacking by a combination of ion partition and ion exclusion3.4 Conclusions3.5 ReferencesChapter 4 51-62Determination of trace amounts of ions in water and salt samples using partition/ion exclusion chromatographic ion stacking4.1 Introduction4.2 Experimental4.3.1 Chemicals4.3.1 Instrumentation and Chromatographic Procedure4.3.2 Preparation of samples and working standard solutions4.3 Results and Discussion4.3.1 Determination of nitrate ion in tap water4.3.2 Determination of trace anions in reagent grade salts4.4 Conclusions4.5 ReferencesChapter 5Conclusions and future outlook 63-64Acknowledgements 65-66List of Publications 67, 指導教員 : 渋川雅美

It has been reported that ion enrichment phenomena are observed in liquid chromatographic processes with an aqueous mobile phase on the columns packed with nonionic materials. However, the mechanism of the ion enrichment is not at all well understood. In this study, we investigated the retention and enrichment behaviors of simple inorganic anions on a C18-bonded silica column and a cross-linked hydroxylated methacrylic polymer gel column with pure aqueous mobile phases containing various electrolytes. We show that the stacking of ionic solutes can successfully be accounted for by the ion partition model, and it takes place due to the effect of the background coion in the eluent and/or sample solution on the distribution of the ions between the bulk water and the water incorporated in the packing material, which acts as the stationary phase. Using the ion exclusion effect of fixed anionic charges on a packing material as well as the ion stacking by partition, we developed a simple and versatile method for effective enrichment of anionic solutes in aqueous solutions. The enrichment factor and the elution time of the stacked ion zone can be predicted by the ion partition model.

Hypothyroidism is a common endocrine disorder resulting from decreased secretion of thyroid hormone. The diagnosis of hypothyroidism is suggested from the clinical and laboratory findings. Its occurrence in childhood is rare. Here we present a case report on this disease with rare presentation of abdominal lump and pervaginal bleeding in childhood. A 7 years old girl admitted in tertiary level hospital with abdominal lump and irregular per vaginal bleeding. Abdominal swelling was gradually increasing in size & associated with lower abdominal pain for last 5 months. On examination the girl was moderately anaemic, mildly oedematous, distended lower abdomen and a mass in left iliac region. Her thyroid function test, serum FSH, serum LH, serum Prolactin was done and high FSH, LH, Prolactin levels were found. USG of lower abdomen revealed bulky uterus and bilateral ovarian cysts. MRI of Brain showed feature of pituitary microadenoma. Finally the patient was diagnosed as primary hypothyroidism and bilateral follicular ovarian cyst with pituitary adenoma developed as its consequence. The case is reported for clinical awareness & to share our experience. CBMJ 2014 July: Vol. 03 No. 02 P: 41-44

Bangladesh is consisting of 30 Agroecological Regions (AEZs) and the applied agricultural research has been conducted based on this. In context of the lack of enough information on mineralogy based on AEZs, an attempt has been taken to study the mineralogy of important soils from all AEZs of Bangladesh in order to provide basic information for applied research. As part of this attempt, the mineralogy of twenty four soils from three representative soil series (Ramgati, Hatiya and Silonia) of AEZ 18, Young Meghna Estuarine Floodplain, has been reported in the current paper. The clay content of the surface soils ranged from 8.7 to 29.4%. According to the USDA system, thirteen soil samples were silt loam, eight were silt and only one was silty clay loam. The