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Graphene Nanoplatelets as a Solid Phase Extraction Sorbent for Analysis of Chlorophenols in Water
Sadanala, Krishna Chaitanya,Chung, Bong Chul The Korean Society for Applied Biological Chemistr 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.6
Graphene nanoplatelets are a novel class of carbon nanostructures. They possess an ultra high surface area, and thus have great potentials for the use as sorbent materials. We herein demonstrate the use of graphene nanoplatelets as an adsorbent material for solid-phase extraction. Surface compositions of graphene nanoplatelets were examined by X-ray photoelectron spectroscopy. Scanning electron and transmission electron microscopies were performed to elucidate the morphology of graphene nanoplatelets. Three chlorophenols, 3-chlorophenol, 4-chlorophenol, and 2,4-dichlorophenols were selected as model analytes and extracted on a graphene nanoplatelets-packed solid-phase extraction cartridge, followed by elution with alkaline methanol. The extracted chlorophenols were identified and quantified by UV-vis spectrophotometer. Under the optimized experimental conditions, good linearity ($R^2$ >0.9969), recovery (95-103%), precision (<12%), and accuracy (< ${\pm}9$%) were achieved. The advantages of graphene nanoplatelets as solid phase extraction adsorbent, such as good reusability and no impact of sorbent drying, have been detailed. The present study proposes a useful method for water sample pretreatment and reveals the potential of graphene nanoplatelets as an excellent sorbent material in analytical processes.
Graphene Nanoplatelets as a Solid Phase Extraction Sorbent for Analysis of Chlorophenols in Water
Krishna Chaitanya Sadanala,정봉철 한국응용생명화학회 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.6
Graphene nanoplatelets are a novel class of carbon nanostructures. They possess an ultra high surface area, and thus have great potentials for the use as sorbent materials. We herein demonstrate the use of graphene nanoplatelets as an adsorbent material for solid-phase extraction. Surface compositions of graphene nanoplatelets were examined by X-ray photoelectron spectroscopy. Scanning electron and transmission electron microscopies were performed to elucidate the morphology of graphene nanoplatelets. Three chlorophenols, 3-chlorophenol, 4-chlorophenol, and 2,4-dichlorophenols were selected as model analytes and extracted on a graphene nanoplatelets-packed solid-phase extraction cartridge,followed by elution with alkaline methanol. The extracted chlorophenols were identified and quantified by UV-vis spectrophotometer. Under the optimized experimental conditions,good linearity (R2 >0.9969), recovery (95–103%), precision (<12%),and accuracy (<±9%) were achieved. The advantages of graphene nanoplatelets as solid phase extraction adsorbent, such as good reusability and no impact of sorbent drying, have been detailed. The present study proposes a useful method for water sample pretreatment and reveals the potential of graphene nanoplatelets as an excellent sorbent material in analytical processes.
( Krishna Chaitanya Sadanala ),( Byung Hwa Jung ),( In Jin Jang ),( Bong Chul Chung ) 한국약제학회 2011 Journal of Pharmaceutical Investigation Vol.41 No.1
Urinary steroid levels were investigated in the treatment of CKD-501, a new anti-diabetic drug candidate. CKD-501 was administered orally at the dosage of 1, 2, 4 mg/day for 7 days to normal men (n=18). Urine was collected before, during and after stopping the drug administration and the urinary level of androgen, estrogen, progestin and corticoids were quantified using GC-MS (gas chromatography-mass spectrometry). Only urinary corticosteroid and an androgen, DHEA levels among all the analyzed steroids, have been found to increase progressively, reaching significant levels on the last day of drug treatment and later declined after the drug treatment is withdrawn. Therefore, it was thought that an increase in the urinary corticoid and DHEA levels could be a characteristic of CKD-501, since it prominently acts on the glucose sensitivity and suppresses the triglyceride levels. In conclusion, it was found that CKD-501, an anti-diabetic drug candidate, affects the glucocorticoid and DHEA levels and it plays a crucial role in glucose homeostasis.
A Metabolomic Approach to Understanding the Metabolic Link between Obesity and Diabetes
Park, Seokjae,Sadanala, Krishna Chaitanya,Kim, Eun-Kyoung Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.7
Obesity and diabetes arise from an intricate interplay between both genetic and environmental factors. It is well recognized that obesity plays an important role in the development of insulin resistance and diabetes. Yet, the exact mechanism of the connection between obesity and diabetes is still not completely understood. Metabolomics is an analytical approach that aims to detect and quantify small metabolites. Recently, there has been an increased interest in the application of metabolomics to the identification of disease biomarkers, with a number of well-known biomarkers identified. Metabolomics is a potent approach to unravel the intricate relationships between metabolism, obesity and progression to diabetes and, at the same time, has potential as a clinical tool for risk evaluation and monitoring of disease. Moreover, metabolomics applications have revealed alterations in the levels of metabolites related to obesity-associated diabetes. This review focuses on the part that metabolomics has played in elucidating the roles of metabolites in the regulation of systemic metabolism relevant to obesity and diabetes. It also explains the possible metabolic relation and association between the two diseases. The metabolites with altered profiles in individual disorders and those that are specifically and similarly altered in both disorders are classified, categorized and summarized.
A Metabolomic Approach to Understanding the Metabolic Link between Obesity and Diabetes
박석재,Krishna Chaitanya Sadanala,김은경 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.7
Obesity and diabetes arise from an intricate interplay between both genetic and environmental factors. It is well recognized that obesity plays an important role in the development of insulin resistance and diabetes. Yet, the exact mechanism of the connection between obesity and diabetes is still not completely understood. Metabolomics is an analytical approach that aims to detect and quantify small metabolites. Recently, there has been an increased interest in the application of metabolomics to the identification of disease biomarkers, with a number of well-known biomarkers identified. Metabolomics is a potent approach to unravel the intricate relationships between metabolism, obesity and progression to diabetes and, at the same time, has potential as a clinical tool for risk evaluation and monitoring of disease. Moreover, metabolomics applications have revealed alterations in the levels of metabolites related to obesity-associated diabetes. This review focuses on the part that metabolomics has played in elucidating the roles of metabolites in the regulation of systemic metabolism relevant to obesity and diabetes. It also explains the possible metabolic relation and association between the two diseases. The metabolites with altered profiles in individual disorders and those that are specifically and similarly altered in both disorders are classified, categorized and summarized.