Standard compensation

In a culture characterized by mistrust, incentives are naturally required, e.g. payment by piece rates in order for the work that needs to be done to be performed somewhat efficiently. Yet anyone who has ever done piece work or similar incentive work knows what employee potential is covered up by piece work and remain untapped by the enterprise. 

It is inconceivable what would happen if an employee decided to implement a reduction in the standard operation time with one of his suggested improvements How would his colleagues treat him  

Although the value-added employee base has many ideas for faster, better, and more efficient performance, the strictures of the system frequently prevent them from ever rising to the surface. 

We need to understand the profit-consuming fact that many smart value-added employees have long had the tools and equipment for better productivity available to them. The institutionalized work preparation division has just not been aware of it. Unfortunately, these employees only use them to reach the level of performance tolerated by the conpany. 

Many employees are already acting as entrepreneurs on their own behalf, namely to earn as much as possible with as little effort as possible. Unfortunately, this behavior which they are almost forced to adopt is not in line with your corporate objectives. 

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Precision The precision of a gas chromatographic analysis includes contributions from sampling, sample preparation, and the instrument. The relative standard deviation due to the gas chromatographic portion of the analysis is typically 1-5%, although it can be significantly higher. The principal limitations to precision are detector noise and the reproducibility of injection volumes. In quantitative work, the use of an internal standard compensates for any variability in injection volumes. 

The muiti-residue method for aiachior, acetochior, and metoiachior determines the concentrations of these anaiytes in groundwater and surface water. This method in-voives the addition of a deuterated intemai standard to the water sampie, concentration of the anaiytes on an SPE coiumn, eiution of anaiytes, concentration of the eiuate to a set voiume, and anaiysis by GC/MS. The use of internai standards compensates for recovery tosses, but separate experiments were conducted to ensure that recoveries were within 70-i20%. The method was vaiidated over the range of 0.05-20 xgL for aii components and is presented in Section 6. 

The CE method was validated in terms of accuracy, precision, linearity, range, limit of detection, limit of quantitation, specificity, system suitability, and robustness. Improved reproducibility of the CZE method was obtained using area normalization to determine the purity and levels of potential impurities and degradation products of IB-367 drug substance. The internal standard compensated mainly for injection variability. Through the use of the internal standard, selected for its close mobility to IB-367, the method achieved reproducibility in relative migration time of 0.13% relative standard deviation (RSD), and relative peak area of 2.75% RSD. 

MS or MS-MS coupled with GC or HPLC has been u.sed for the determination of DAPs in urine (Bravo et al., 2002 Hardi and Angercr, 2000 Hernandez et al., 2004 Oglobine etal.. 2001). The use of GC/MS or GC/MS-MS requires alkylation of DAPs in order to render them volatile for GC separation. HPLC coupled with MS or MS-MS has the advantage that DAPs need not be alkylated. Fimhermore. the use of labeled (isotopic) internal standards compensates for the losses in recovery and improves precision. However, the use of labeled internal standards is very expensive since these compounds have to be custom synthesized. 

Sodium and potassium in serum are determined in the clinical laboratory by atomic-emission spectroscopy, using an instrument designed specifically for this purpose [5]. Two filter monochromators isolate the sodium and potassium emission lines. A lithium internal standard is used, and the ratios of the Na/Li and K/Li signals are read out on two separate meters. The internal standard compensates for minor fluctuations in flame temperature, aspiration rate, and so forth. A cool flame, such as air-propane, is used to minimize ionization. Typically, the serum sample and standards are diluted 1 200 with a 100 ppm Li solution and aspirated directly. The instrument can be adjusted to read directly in meq/1 for sodium and potassium by adjusting the gain while aspirating appropriate standards. 

There are at least 53 separate workers compensation laws in the United States. Attempts to standardize compensation laws or create federal standards for them have not progressed very far. Each of the 50 states has its own workers compensation law. Some states change their laws to reduce the overall costs for employers in comparison to neighboring states. That is a strategy to entice employers to relocate in their state or to stay there. 

The more volatile monomers vinyl chloride, butadiene, and acrylonitrile can be determined by dissolution of the polymer and analysis of the equilibrated headspace above the polymer solution. By this method it was possible to determine vinyl chloride and bntadiene at the 0.05 ppm level and acrylonitrile down to 0.5 ppm. The injection of water into polymer solutions containing styrene and 2-ethylhexyl acrylate monomers prior to headspace analysis greatly enhanced the detection capability for these monomers making it possible to determine styrene down to 1 ppm and 2-ethylhexyl acrylate at 5 ppm. Incorporation of polymer into the calibration standards compensates for the effect which the polymer matrix has upon the equilibrium partitioning of the monomer between the solution and head space. The relative precision and error in the determination of these monomers near the quantitation limit was found to be less than 7%. 

An internal standard, if properly chosen and used, can compensate tor several types of both random and systematic errors. Thus, if the analyte and internal-standard signals respond proportionally to random instrumental and method fluctuations, the ratio of these signals is independent of such fluctuations. If the two signals are inlluenced in the same way by matrix effects, compensation of these effects also occurs. In those instances where the internal standard is a major constituent of samples and standards, compensation for errors that arise in sample preparation, solution, and cleanup mas also occur. 

Other types of physical interference effects include those affecting the nebulization/sample introduction process. These sample transport effects, which result from differences in viscosity, surface tension, and volatility, can be minimized by dilution.The use of a deHvery pump to transport the sample solution to the nebulizer will normalize these effects to a limited extent. Whenever mineral acids are used in sample decomposition or preservation, equivalent quantities added to the calibration standards compensate for differences in solution properties and hence minimize sample transport effects. 

The internal standard procedure requires that every test solution (sample and standard) have the same concentration (or a known concentration) of an internal standard element that is not present in the original sample. The internal standard is usually combined with the dilution solvent. Internal standard compensation is typically handled in one of two different ways, which can be summarized as follows. 

Calibration curves can be constructed differently, depending on the implementation of internal standard compensation. 

When internal standard compensation is handled by multiplying all results for a certain test spedmen by the ratio of the actual internal standard concentration to the determined internal standard concentration, the calibration curve is, in effect, a plot of 1(e) - I(Be)) versus analyte concentration. 

The operation is quite simple One sets the frequency to the lowest value, adjusts the gain and phase to the desired sensitivity using a special calibration standard discussed below and performs a zero-compensation on a defect free zone of the standard. Now one is ready to test. As one slides the probe across the surface of an aluminum structure, a signal response will be indicative of the presence of corrosion or of the presence of a subsurface edge. 

An extension of these metliods to 3D is the Feldkamp algorithm [7], a standard in 3D-tomographic reeonstruction today. In this case off-midplane voxels are taken into eonsideration through weighted filtered 3D-baekprojection. llie weighting compensates for the longer way an oblique ray has to travel. 

The temperature compensator on a pH meter varies the instrument definition of a pH unit from 54.20 mV at 0°C to perhaps 66.10 mV at 60°C. This permits one to measure the pH of the sample (and reference buffer standard) at its actual temperature and thus avoid error due to dissociation equilibria and to junction potentials which have significant temperature coefficients. 

Examine a procedure from Standard Methods for the Analysis of Waters and Wastewaters (or another manual of standard analytical methods), and identify the steps taken to compensate for interferences, to calibrate equipment and instruments, to standardize the method, and to acquire a representative sample. 

When possible, quantitative analyses are best conducted using external standards. Emission intensity, however, is affected significantly by many parameters, including the temperature of the excitation source and the efficiency of atomization. An increase in temperature of 10 K, for example, results in a 4% change in the fraction of Na atoms present in the 3p excited state. The method of internal standards can be used when variations in source parameters are difficult to control. In this case an internal standard is selected that has an emission line close to that of the analyte to compensate for changes in the temperature of the excitation source. In addition, the internal standard should be subject to the same chemical interferences to compensate for changes in atomization efficiency. To accurately compensate for these errors, the analyte and internal standard emission lines must be monitored simultaneously. The method of standard additions also can be used. 

A pH electrode is normally standardized using two buffers one near a pH of 7 and one that is more acidic or basic depending on the sample s expected pH. The pH electrode is immersed in the first buffer, and the standardize or calibrate control is adjusted until the meter reads the correct pH. The electrode is placed in the second buffer, and the slope or temperature control is adjusted to the-buffer s pH. Some pH meters are equipped with a temperature compensation feature, allowing the pH meter to correct the measured pH for any change in temperature. In this case a thermistor is placed in the sample and connected to the pH meter. The temperature control is set to the solution s temperature, and the pH meter is calibrated using the calibrate and slope controls. If a change in the sample s temperature is indicated by the thermistor, the pH meter adjusts the slope of the calibration based on an assumed Nerstian response of 2.303RT/F. 

Photomultipliers are used to measure the intensity of the scattered light. The output is compared to that of a second photocell located in the light trap which measures the intensity of the incident beam. In this way the ratio [J q is measured directly with built-in compensation for any variations in the source. When filters are used for measuring depolarization, their effect on the sensitivity of the photomultiplier and its output must also be considered. Instrument calibration can be accomplished using well-characterized polymer solutions, dispersions of colloidal silica, or opalescent glass as standards. 

In addition, most devices provide operator control of settings for temperature and/or response slope, isopotential point, zero or standardization, and function (pH, mV, or monovalent—bivalent cation—anion). Microprocessors are incorporated in advanced-design meters to faciHtate caHbration, calculation of measurement parameters, and automatic temperature compensation. Furthermore, pH meters are provided with output connectors for continuous readout via a strip-chart recorder and often with binary-coded decimal output for computer interconnections or connection to a printer. Although the accuracy of the measurement is not increased by the use of a recorder, the readabiHty of the displayed pH (on analogue models) can be expanded, and recording provides a permanent record and also information on response and equiHbrium times during measurement (5). 

In many appHcations temperature compensation is added to calculate level (or volume) to an industry standard value, usually the American Petroleum Institute (API). 

The RMS-800 provides steady-shear rotational rates from 10 to 100 rad/s and oscillatory frequencies from 10 to 100 rad/s. An autotension device compensates for expansion or contraction. With the standard 25- and 50-mm parallel plates, the viscosity range is 50-10 mPa-s, and the shear modulus range is 8 x 10 to 10 N/m. These ranges can be expanded with nonstandard plates, cones, and a Couette system. The temperature range is 20-350°C (-150 0 optional). 

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