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Spectrophotometric Determination of Barbituric Acid by Coupling with Diazotized Nitroanilines
| Content Provider | Semantic Scholar |
|---|---|
| Author | ابراهيم, Batool B. Ibraheem بتول بشير |
| Copyright Year | 2011 |
| Abstract | A simple spectrophotometric method for the trace determination of barbituric acid (BA) has been established. The method is based on the coupling reaction of barbituric acid with diazotized nitroaniline in basic medium to form an intense yellow-water soluble and stable mono azodyes which shows maximum absorption at 418, 380, and 370 nm with diazotized o-, mand p-nitroanilines, (DONA, DMNA, and DPNA), respectively. A plot of absorbance versus BA concentration was linear to a certain limit, indicating that Beer's law was adhered to over the range 5-300 μg of BA/25 ml final volume (i.e., 0.2-12 ppm) with a molar absorptivity of 1.998×10, 2.328×10, and 2.184×10 l mol cm for DONA, DMNA, and DPNA, respectively. Sandell sensitivity indexes were 0.0064, 0.0055, and 0.0059 μg cm, while the relative errors were -3.365 to 0.904%, -3.325 to 0.138%, and -2.053 to 2.679% for DONA, DMNA, and DPNA, respectively. The relative standard deviation (RSD) were 0.489 to 3.330, 0.897 to 2.209 and 0.059 to 3.689 for DONA, DMNA and DPNA, respectively. The optimum conditions for the color reaction, nature of dye, stability constant and the interference of variety of organic compounds had been investigated. The method has been successfully applied to the determination of barbituric acid in Tigris water river. The proposed method for the determination of barbituric acid is simple, sensitive, very low cost, has a wide analytical range and without the need for heating or solvent extraction techniques. keywords: Azo-dye, Barbituric acid, Diazotized Nitroanilines, Spectrophotometric determination. ـــــــــــــــــــــــــــــــــــــــ ــــ ـــــــــــــ ارتقاب كرويتيبرابلا ضماحل يفيطلا ريدقتلا ن توزؤملا نيليناورتيان عم ه صخلملا يتيبرابلا ضماح نم رغصلا يف ةيهانتم تايمك ريدقتل ةطيسب ةقيرط تيبثت مت و ةقيرطلا دمتعت ،كير كيرويتيبرابلا ضماح نارتقا لعافت ىلع ك عم و ةغبص نيوكتل يدعاق طيحم يف توزؤملا نيليناورتيان فشا ةيداحأ يطعت يتلاو ءاملا يف ةبئاذ ءارفص ىلعأ صاصتما ةي دنع 418 و 380 و 370 تاضوعملل رتمونان Batool B. Ibraheem 57 DONA و DMNA و DPNA و يلاوتلا ىلع . ةيصاصتملاا ينحنم رهظأ ً اطخ هنأ ىلع دكؤي يذلاو ً اميقتسم رت ىدم دنع ريب نوناق عبتي كيرويتيبرابلا ضماح زيك 5 300 مارغوركيام / 25 رتللم يأ نأ ) 0.2 12.0 ( ءزج ب نويلملا بو ماعم ل اصتما يرلاوم ص 1.998×10 ، 2.328×10 و 2.184×10 ل رت . لوم 1 . مس 1 ل تاضوعمل DONA و DMNA و DPNA عو يلاوتلا ىل . تناكو ةللاد لدناس ةيساسحلل 0.0064 , 0.0055 و 0.0059 مس مارغوركيام 2 نم يبسنلا أطخلا غلب امنيب ، 3.365 ىلإ 0.904 % و 3.325 ىلإ 0.138 % و 2.053 ىلإ 2.679 % تاضوعملل DONA و DMNA و DPNA لعو يلاوتلا ى . ةفاضلإاب صلاختسلاا ةينقت لاو ةرارحلا ةجرد يف مكحتلا ىلإ جاتحت لاو ةعيرسو ةطيسب تناك ةقيرطلا نأ ىلإ ،تابيذملاب متو امك ت ةسارد ظلا فور ىلثملا لعافتلل تلاخادتملاو ةيرارقتسلاا تباثو ةغبصلا بيكرتو . دقلو تقبط ةقيرطلا حاجنب ل ريدقت كرويتيبرابلا ضماح يف ءام رهن ةلجد . ةلاادلا تاملكلا : يفيطلا ريدقتلا ،نيليناورتان ،كيرويتيبرابلا ضماح ،وزلآا ةغبص . ــ ـــــــــــــــــــــــــــــــــــــــــــــ ـــــــ INTRODUCTION Barbituric acid {2,4,6(1H,3H,5H)-pyrimidinetrione}is widely used in the preparation of barbiturates, dyes and polymerization catalysts (Hawley, 1981), pharmaceutical preparation and indicators (Acheson, 1967), textile (Brown, et al., 1970) and also been identified as an intermediate in many processes. It is well known that barbituric acid itself has no affect on the central nervous system (Wesson and Smith, 1977) however it is used as a precursor to medical barbiturates which can be lethal in excessive amounts (Matther, 1971). Therefore, the determination of trace amounts of barbituric acid is very important in studies for both biological and industrial processes. Different methods such as chromatography (Cela et al., 2000), mass spectrometry (Van Langenhove et al., 1982) capillary electrophoresis (You, 2000) infra-red spectrophotometry (Pawelczyk, et al., 1972) spectrophotometry (Medien, 1996), (Medien and Zahran, 2001) and (Bartzatt, 2002) and colorimetry (Nematollahi and Hesari, 2001) also have been reported for determination of barbituric acid. Some of these methods are time consuming and suffer from lack of selectivity or good sensitivity and/or have short linear dynamic range or have higher limit of detection and/or use reagents not commercially available. Recently, (Nematollahi and Hesari, 2001) used controlled potential colorimetric technique for barbituric acid analysis in the range of 1-200 mmol. The method is not very sensitive and has several interferences. (Medien and Zahran, 2001) used 1,4naphthoquinone as a spectrophotometric reagent for barbituric acid determination, but the method has a high limit of determination 2.7-61.5 mg ml and has many interfering substances for barbiturate determination. (Bartzatt, 2002) used sodium nitrite as a suitable reagent for colorimetric analysis of barbiturate, with linear range of 18.7-225 mg ml. Therefore, the need for a fast, low cost and sensitive method is obvious, especially for routine quality control analysis. This spectrophotometric procedure is suitable for determination of barbituric acid at trace level. Spectrophotometric Determination of Barbituric. 58 EXPEREMINTAL Apparatus Spectral measurements were made on a Shimadzu UV-1601 recording spectrophotometer. All the pH measurements were done on Elico pH meter (LI-10T). Reagents and Chemicals All chemicals used were of highest purity. Standard barbituric acid solution (100 μg/ml). A 0.1000 g of barbituric acid dissolved in 1L distilled water. This solution was prepared weekly. Diazotized nitroanilines reagents solution, (5×10 M). A 0.0691g of o-, m-, and pnitroanilines (Fluka) were dissolved in about 8 ml of distilled water. Then 1.6 ml of 5 M hydrochloric acid solution was added ( the solution was heated in case of o-nitroaniline only), the clear mixture was then transferred to a 100ml volumetric flask and cooled to 05C in an ice bath. A 3.5 ml of 1% of sodium nitrite (NaNO2) solution was added and the mixture was stirred vigorously. After 5 min., the solution was made up to volume in 100-ml volumetric flask with cold distilled water. The solution was kept in a brown bottle in refrigerator and was stable for five days at least. Hydrochloric acid solution (5 M). This solution was prepared by appropriate dilution of concentrated hydrochloric acid (Fluka) with distilled water. Na2Co3 solutions 2%. Sodium carbonate solution were prepared by appropriate dilution of concentrated ampoule solution (Fluka) with distilled water and then transferred to a plastic bottle. The other bases (sodium hydroxide, potassium hydroxide, sodium acetate, sodium bicarbonate, sodium formate) 2% solutions were prepared by dissolving 2.0 g of base in 100-ml volumetric flask with distilled water and then transferred to plastic bottle. Surfactant solutions (1×10 M). These solutions were prepared by dissolving 0.0365 g of SDS and 0.0289 g of CTAB each in 20 ml distilled water and the volume was made to 100 ml in volumetric flask with distilled water. Triton X-100 (1%). This solution was prepared by completing 1.00 ml Triton X-100 in 100-ml volumetric flask with distilled water. Foreign compounds (Fluka) solutions (100 μg/ml). These solutions were prepared by dissolving 0.1000 g of the foreign compound in 1L distilled water. River water: This water taken from the middle of Tigris river in forest place in Mosul city was filtered and then 25, 50, 75 and 100 μg barbituric acid were added and the recommended procedure was applied without any further treatment. Procedure Transfer aliquots of aqueous sample solutions containing (5-300μg) of barbituric acid into a series of 25-ml calibrated flasks. To each flask, 1ml of reagent (DONA, DMNA, and DPNA) solutions and 1ml of 2% KOH, 1 ml of 2% CH3COONa and 0.5 ml of 2% NaOH solutions were added, respectively. The solutions were mixed and diluted to the mark with distilled water. The absorbance of each colored solution at 418, 380, and 370 nm were Batool B. Ibraheem 59 |
| Starting Page | 56 |
| Ending Page | 71 |
| Page Count | 16 |
| File Format | PDF HTM / HTML |
| Volume Number | 22 |
| Alternate Webpage(s) | https://www.iasj.net/iasj?aId=32476&func=fulltext |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
