Determination of copper in copper alloy by flame atomic absorption spectrometry with AA-1800 - Master's thesis - Dissertation

Key words: flame atomic absorption spectrometer; copper content in alloy; aesthetic analyzer ; AA-1800C

Introduction: Copper alloys are widely used in the industrial field, especially for the high-speed rail construction in the current use of copper alloy materials for the construction of circuit lines. Therefore, the use of copper alloys on circuit power systems is particularly important. Tests for copper alloy materials are also particularly stringent, but the method for determining copper in existing test copper alloys is cumbersome and complicated. Therefore, it is considered to establish a simple standard curve method test method, which can avoid the influence of copper matrix and can accurately determine the copper content analysis method. This paper describes the use of a sample analysis method to determine Cu in copper alloys directly by flame atomic absorption spectrometry using a 249.2 nm absorption line of copper. According to the 324.8nm standard addition method and the two analytical methods, the content values ​​are the same, and a simple test method for determining copper elements in the copper alloy is obtained. This method improves the analysis accuracy and simplifies the analysis and determination process. 1 Experimental Section 1.1 Apparatus and Equipment AA-1800 Atomic Absorption Spectrometer (MEAS China). Adjustable hot plate. Ultra pure water machine. Cu hollow core cathode lamp. 1.2 Reagents and solutions (1) Nitric acid, excellent grade, 68-70%. (2) High purity deionized water. Resistivity ≥ 18 MΩ.cm. (3) Copper standard solution (concentration 1000ug/ml). 1.3 Sample processing and testing 1) Sample preparation: Accurately weigh 0.1106g copper alloy sample into a 100ml beaker. Add 5 ml of concentrated nitric acid and heat it on a hot plate at low temperature to add a small amount of deionized water to prevent the sample from reacting violently. After heating, the nitric acid is exhausted and then taken down and cooled at room temperature. After cooling, transfer it to a 50ml volumetric flask for testing. 2) Standard curve: (1) Standard curve method curve preparation: Take copper standard solution 1000ug/ml Accurately measure 200ul, 400ul, 800ul into 3 10ml volumetric flasks, add 0.5ml concentrated nitric acid, and dilute with deionized water, the solution The concentrations are 20, 40, 80 ug/ml, respectively. Directly determine the standard curve and determine the sample solution 1. (2) Standard addition method: Transfer 1.0ml from sample solution 2 to add 4 10ml volumetric flasks, tube 1 directly to deionized water to volume, tubes 2, 3, 4 respectively A 1000 ug/ml copper standard solution was added at 25, 50, 75 ul, and the concentration was taken as 0, 0.5, 1.0, 1.5 ug/ml, and determined by a standard addition method. Sample solution 1: Dilute the sample solution to a constant volume 1000 times. Sample solution 2: Dilute the sample solution to a constant volume by 50 times. 3) Instrument conditions: (1) Standard curve method: lamp current: 3 mA, high voltage: 400 v, spectral bandwidth: 249.2 nm. Acetylene flow: 2.0 L/min. (2) Standard addition lamp current: 3 mA, high voltage: 409 v, spectral bandwidth: 324.9 nm. Acetylene flow: 2.0 L/min. 4) Analysis results: By comparing the results of the two methods, it can be seen that when the wavelength of 249.2 nm of the secondary sensitive line of copper is used, the standard curve method is directly used, which can effectively avoid the deviation of test results due to matrix interference. Big problem. Reduce the interference factor for copper in the sample by reducing the sensitivity of the test. This method is convenient, easy to operate and has high accuracy. Key words: flame atomic absorption spectrometer; copper content in alloy; aesthetic analyzer ; AA-1800C