Copper calibration curves

Figure 11.3 Copper calibration curves (324.8 mm) measured with the Zeeman 5000...

Figure 2.4 Copper calibration curves (24.8 nm) measured with a Zeeman spectrometer. Source Author s own files.

Construct a calibration curve using the synthetic standard solution add the standard copper solution immediately before the reagent. 

Figure 26.3, represents the typical calibration curves of copper at 3428 A, where ... 

Figure 13 shows the calibration curve of phase-lag for the nickel foils of various thickness. This result suggests the possibility of estimating the thickness of plated materials on the metal. Figure 14 shows the PAXAS spectrum of nickel-plated copper. In the photoacoustic amplitude spectrum, EXAFS of copper at the subsurface of sample was still detected clearly. This means that PAXAS method can be applied... 

Prepare 30-fold and 50-fold dilutions of the test solution. Add 1.25 ml of a mixture prepared the same day by combining 2.0 ml of a 20 g/1 solution of copper sulphate R in water R, 2.0 ml of a 40g/l solution of sodium tartrate R in water R and 96.0 ml of a 40 g/1 solution of sodium carbonate R in 0.2M sodium hydroxide to test tubes containing 1.5ml of water R (blank), 1.5ml of the different dilutions of the test solution or 1.5 ml of the reference solutions. Mix after each addition. After approximately 10 min, add to each test-tube 0.25 ml of a mixture of equal volumes of water R and phosphomolybdotungstic reagent R. Mix each addition. After approximately 30 min, measure the absorbance (2.2.25) of each solution at 750 nm using blank as the compensation liquid. Draw a calibration curve (from the absorbances of the eight reference solutions the corresponding protein contents and read from the curve the content of protein in the test solution. 

Copper, Chromium, Manganese, and Nickel. The analytical method for determining copper, chromium, manganese, and nickel involves digesting the coal with nitric and perchloric acids, fusing the residue with lithium metaborate, and determining the combined digestion and leach solutions by atomic absorption spectrophotometry. Since there is no standard material to analyze for the construction of calibration curves, the standard additions method is used for the assay. While this method increases the time required for analysis, it helps to eliminate the effect of the matrix. 

Conditioning of the manganese oxide suspension with each cation was conducted in a thermostatted cell (25° 0.05°C.) described previously (13). Analyses of residual lithium, potassium, sodium, calcium, and barium were obtained by standard flame photometry techniques on a Beckman DU-2 spectrophotometer with flame attachment. Analyses of copper, nickel, and cobalt were conducted on a Sargent Model XR recording polarograph. Samples for analysis were removed upon equilibration of the system, the solid centrifuged off and analytical concentrations determined from calibration curves. In contrast to Morgan and Stumm (10) who report fairly rapid equilibration, final attainment of equilibrium at constant pH, for example, upon addition of metal ions was often very slow, in some cases of the order of several hours. 

An OSWV was performed and the peak current density of copper was measured. The concentration of copper was determined from the standard calibration curve. Subsequently, the concentration of copper in the original lake water sample was determined. 

Some results of the calibration uncertainty evaluation, due to the linear calibration curve of copper determination cm by molecular absorption spectro (photo)-metry using a Cecil 2020 instrument are illustrated in Table 2. Note that at the end of the linear range (0-10) mg/1 the calibration uncertainty is bigger than in the middle of the linear range for a concentration of 0.987 mg/1 copper the uncertainty component due to the calibration is 3% and for a concentration of at 6.010 mg/1 copper the uncertainty component due to the calibration is 0.56%. 

The combined data provide a ready means by which to compare and select appropriate assays for application in cellulase-catalyzed cellulose saccharification experiments. Products in such experiments are expected to include glucose cellobiose and, potentially, some cellooligosaccharides. Optimum reducing sugar assays would have equivalent molar color yields for these soluble products. As shown in Table 3, this optimum situation only applies to the two copper-based assays (Nelson, BCA). Because of their importance with respect to the analysis of insoluble cellulose (discussed next), calibration curves reflecting the molar color yields for the DNS and BCA assays are presented in Fig. 1. 

COPPER CONCENTRATION (ppm) Fig. 3. Calibration curves for different copper absorption lines. 

Plot die absorbance of each standard solution against the concentration of copper, and read off the concenhation in the sample. The calibration curve should be linear for concenhations in the range 0 to 2 lag/ml. 

Method. Dilute 1 ml of the serum sample with sufficient of a 6% solution of butan-l-ol to produce 10 ml, mix, aspirate into an oxidising (blue) flame, and record die absorbance at 324.7 nm. Repeat die procedure with 1 ml of each of the diluted standard solutions, and with 1 ml of sodium chloride-potassium chloride solution (blank). Plot the absorbance of each standard solution against the concentration of copper, and read off the concenhation in the sample. The calibration curve may be non-linear. 

Only the wavelength intensities were used in this analysis since the concentrations generated by the program are semiquantitative in that the concentration is an average of the spectra scanned for each element. Copper standards were prepared, arced, and scanned along with the copper samples. Calibration curves were drawn for each analytical standard. The wavelength intensities of the sample spectra were compared with these curves and the quantitative trace element composition derived. 

Fourteen standard copper and brass alloys, the compositions of which have been certified by the National Bureau of Standards, have been used to calculate the concentrations of various elements in the coins (NBS C-1100. 1101, C-1102, 1106, C-1109, C-1111, C-1112, C-lllS, 1116, C-1120, 63C, 62D, 157A, and 158A). All standards were prepared metallographi-cally, ending with a diamond polish to obtain a surface representative of the interior of the standard. Excellent calibration curves were obtained with very good precision for both standards and coins, the calculated standard deviation is about 0.003% for Fe, 0.004% for Ni, 0.005% for Ag, 0.002% for Sn, 0.004% for Sb, and 0.003% for Pb. 

In the spectroscopic analysis of many substances, a series of standard solutions of known concentration are measured to generate a calibration curve. How would you prepare standard solutions containing 10.0, 25.0, 50.0, 75.0, and 100. ppm of copper from a commercially pro-... 

The quantitative estimation of copper in the postmodified material was carried out by AAS following complete dissolution using an HF/HNO3 mixture." The amount of copper was determined by a calibration curve method using a copper lamp of wavelength 324.8 nm and air/acetylene fuel (ratio of 3 1). 

Two x-ray fluorescence spectrometers were used for the analyses a General Electric XRD-6 for iron, copper, tin, and antimony, and a General Electric XRD-5 for nickel, silver, and lead (the latter machine has updated electronics and gave superior results for these three elements). Four certified standards from the National Bureau of Standards were used for each element to obtain a straight line calibration curve using linear regression (10). The experimental conditions used for the determination of each element were given by Carter et al. (10). 

Although increasing the quantity of APCD added in the extraction changed the slope of the calibration curves but little, it had a profound effect on the calculated concentration of nickel, lead, and cadmium. In Figure 5a, a definite increase is observed in the concentration of cadmium, lead, and nickel as the quantity of 5% APCD added per 800 ml was increased beyond approximately I ml. Figure 5b presents the results for copper and zinc. Copper is unaffected by the quantity of APCD added. The case for zinc is less clear, no doubt because of the decrease in calibration curve slope and the resulting decrease in precision as the quantity of APCD is reduced below 1 ml per 800 ml of sample. The... 

A calibration curve obtained with standard protein solutions [e.g., bovine serum albumin (BSA)] is used to obtain total protein in the unknown. Under optimum conditions, and in the absence of reactive side chains, it has been shown that two electrons are transferred per tetrapeptide unit however, proteins, with significant proline or hydroxyproline content, or with side chains that can complex copper (such as glutamate) yield less color. The side chains of cysteine, tyrosine and tryptophan contribute one, four and four electrons, respectively.3 Note that different proteins will produce different color intensities, primarily as a result of different tyrosine and tryptophan contents. 

With reagents prepared in advance, the Lowry assay requires 1 h. A 400-pL sample is required, containing 2-100-pg protein (5-250 pg/mL). Nonlinear calibration curves are obtained, due to decomposition of the Folin reagent at alkaline pH following addition to the sample that results in incomplete reaction. Interferences include agents that acidify the solution, chelate copper, or cause reduction of cop-per(II). 

Copper(II) forms a 1 1 complex with the organic complexing agent R in acidic medium. The formation of the complex can be monitored by spectrophotometry at 480 nm. Use the following data collected under pseudo-first-order conditions to construct a calibration curve of rate versus concentration of R. Find the concentration of copper(Il) in an unknown whose rate under the same conditions was 7.0 X 10 A s . ... 

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