Aluminum standard curve

For each patient sample, 10 and 20 pi of leukocyte homogenate are transferred to individual wells on the microtiter plate. As two different incubation times are necessary, the same volumes of all samples are also pipetted into the lower part of the plate. Subsequently, 100 pi of substrate buffer is added to each well and the volume is adjusted to a total of 150 pi by adding sodium acetate buffer containing barium acetate. Arylsulfatase A will be inhibited in the presence of barium ions. The plate is briefly shaken, sealed with tape, and covered with aluminum wrapping. Incubation is carried out at 37°C for 30 min (upper half including the standard curve) and 90 min (lower half). The reaction is stopped with 200 pi stop solution and the absorbance is read at 490 nm. 

Domingo et al. [107, 108] used ultrapure nitric acid for sample digestion, performed all specimen manipulation in a laminar flow hood, carried out readings of a blank (reagents only) for each group of samples and, to minimize matrix effects, prepared the standard curves for aluminum determination by the standard addition method. 

Aspirate a 1 10 dilution of Sample Solution into the spectrophotometer, read the absorbance in the same manner, and by reference to the standard curve, determine the concentration (Cj of aluminum, in micrograms per milliliter, in the Sample Solution. 

Set a suitable atomic absorption spectrophotometer to a wavelength of 309.3 nm. Adjust the instmment to zero absorbance against water. Prepare and read the absorbance of four aqueous solutions containing 5, 10, 20, and 50 xg/mL of aluminum, in the form of the chloride, and plot the standard curve as absorbance versus concentration of aluminum. 

When optical density of aluminum standards prepared by dissolving either aluminum wire in HC1 solution or aluminum sulfate in water is measured as a function of aluminum concentration using the modified procedure, curves of the type shown in Figure 1 are obtained. Optical density values plotted on this figure, which are for duplicate sets of experiments, were read about 30 minutes after having added the 2 ml of hydroxylamine hydrochloride. The straight line curve appears to obey Beers law at least up to 0.05-0.06 mg of aluminum. The pH of the standard solutions before analysis was in all cases below 3. 

Preparation of Standards. Standards for ash analysis were prepared from commercially available pure salts in aqueous solution with appropriate acids addition where necessary to match acid concentrations in the samples as well as to hold materials in solution. Master standard solutions were prepared so that serial dilutions for the construction of working curves were possible. A constant amount of silicon and aluminum (equivalent to 20% Si-5% Al) interference solution was added to each set of standards along with lithium tetraborate to carefully match... 

Figure 7. LSF calibration curve of vinyl silanized aluminum hydroxide powder standards shown in Fig. 6.

A second process using complex as the catalyst was independently developed by the Standard Oil Company (Indiana) and by the Texas Company (25,26). A simplified flow diagram of this liquid-phase process is shown in Figure 17. A portion of the dried and heated feed passes through a saturator where aluminum chloride is picked up in accordance with the solubility curve shown in Figure 8. The total feed combined with re( y< le hydrogen chloride enters the bottom of the reactor and... 

X-Ray diffraction experiments (XRD) are perfonned on a curve position sensitive detector INEL CPS 120 which allows a simultaneous collection of diffracted beams in the range 5° < 2 0 < 125°, with the monochromatized CuKai radiation. Powder samples are manually compacted on windowed aluminum holders. After typically one hour of accumulation, patterns are analyzed with the DIFFAC-AT Siemens software program, a-alumina is used as an internal standard. 

Using the 2000-ppm BTEX stock reference solution, prepare a series of calibration standards in which the BTEX is present in 10 mL DDI contained in a 22-mL HS vial with PTFE/silicone septa and aluminum crimp caps. Refer to the calibration in Step 2 for reference as you prepare a series of working calibration standards for HS GC analysis. Following the development of a calibration curve, inject the ICV (only one injection per vial is acceptable in HS GC) and then one or more of the gasoline-contaminated aqueous samples. 

Electric hygrometer - utilizing a substrate, such as a thin film of polymer or aluminum oxide. Water from a sample is absorbed by the film that causes changes in the electrical properties of the film, such as capacitance or resistance. The change of the electrical quantity is related to the amount of water vapor contained in the gas sample and the amount of water is calculated by use of a calibration curve derived from standards. 

---