Calculation of Results

The potency ratio is obtained from the value of antilog M. 

Similar calculations can be applied for three or more doses and worked examples are given in several references.  

CO2 removal agent A CO2 scrubber is used in the purification tube (16) to remove any traces of CO2 from the reference gas. Soda lime and Ascarite (sodium hydroxide coated silica Thomas Scientific Inc., Swedesborough, NJ, USA) are good choices. 

In the first step, raw voltage readings v (mV) are corrected from the measured NDIR cell pressure p (kPa) during CO2 measurement versus the standard barometric pressure p° (101.325 kPa). It has been foimd empirically (Welles and Eckles, 1991) that pressure affects the voltage signal in a linear fashion  

The CO2 mole fraction x(C02) (pmol/mol = ppnnv) is then calculated from the pressure-corrected voltage readings v (mV) on the basis of the calibration pwlynomial  

In the next step the CO2 mole fraction ac(C02) is linearly corrected for any deviation of the cell temp erature T (K) during the CO2 measurement from the calibration tempjerature T° (K). Welles and Eckles (1991) have shown that the mole fraction is scaled linearly with the inverse of the absolute tempjerature  

For very accurate measurements the non-ideal behaviour of CO2 has to be taken into account, Le., fugadty has to be used instead of partial pressure. This is the case if the results are to be used to calculate other parameters of the CO2 system in seawater. The fugacity can be calculated from a knowledge of the virial expression of the equation of state for CO2. For the binary mixture C02-air the fugacity of CO2 (/(CO2)) is given by 

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With dote(Tors that count x-ray quanta, the time to a given number of counts is often used in the calculation of result s in stead of ihe number of counts iV, which is analogous to an output current,/.)... 

Color Diluting Solution. This is prepared by mixing 5 volumes of absolute ethyl alcohol, 1 volume of concentrated hydrochloric acid, and 4 volumes of 2 to 1 sulfuric acid. It is made up just before use. (In the equation for calculation of results, this solution is referred to as Solution B.)... 

Fig. 2.4. UV spectra for nitrofurantoin, showing calculation of results by First Derivative (FD). Top graph shows UV absorbance (A) versus pH. Lower graph shows dA/dpH versus pH. The pKa result (6.91) is indicated by the position of the peak maxima on the pH axis.

Note that it is highly desirable that the identity of every sample is confirmed before analysis, and that samples are adequately pure for the measurement in question. In the pH-metric methods, the sensor is a pH electrode and cannot distinguish between analyte and impurity. In the methods that depend on UV absorbance, if a sample contains an impurity with stronger absorbance than the sample, then the calculation of results from experimental data is complicated. Combinatorial samples are by nature poorly characterized, and even in the chromatographic methods in which analyte and impurity will be separated, it may be difficult to assign the peaks unambiguously. It is therefore advisable to purify samples before they are submitted for analysis of log D and pKa. 

The theoretical yield of the method is less than 100%, as only 80 - 90% of the aqueous phase is removed after back-extraction. The actual yield obtained by 54 Mn counting was 69.5 7.8%, and this can be allowed for in the calculation of results. Environmental Protection Agency standard seawater samples of known manganese content (4370 ng/1) gave good manganese recoveries (4260 ng/1). 

Total updated media volume must be included in the sample data, and the calculation of results. 

The TRAACS 800+ is controlled by a personal computer and the features provided include complete interactive control via keyboard or mouse calculation of results as necessary taking into account baseline or sensitivity drift, graphical output of calibration curves for all calibration types—either Hnear or non-hnear, input facility for sample identification data allowing storage on disc and real-time results together with chart traces on a computer printer. The programs allow easy access to input or data files and connection to other computers, and gives system performance verification to CLP standards and built-in QC charts. 

I have included self-assessment exercises to bring out the keypoints in most of the chapters and there is particular emphasis on simple arithmetical calculation of results from analytical data because, although this is easy after practice, the decline in arithmetical skills at undergraduate level requires some remedial attention. 

Calculation of Results from Differential Viscometry and SEC. The familiar relationship first expressed by Mark (25) and Houwink (26) in the 1940 s is central to the concept of universal calibration first suggested by Benoit et al. (27). In this relationship,... 

Calculation of result in percent of label claim for each sample... 

Calculation of results from mass/weighing to mass/average mass... 

Calculation of Results. The total calcium and magnesium ion content X (in mg-equiv per litre of the water being studied) is calculated by the following formula ... 

CALCULATION OF RESULTS. The ratio of the two peaks is measured after triangulation of the areas R. The concentration of preg-nanediol is calculated from that of the standard by the expression ... 

CALCULATION OF RESULTS. Peak area measurement was done by triangulation. The equation below would be used for the calculation of the amount of steroid in 20 cm3 urine ... 

CALCULATION OF RESULTS. Peak heights are measured in millimeters and the following equation is used to calculate the amount of cholesterol in the unknown ... 

Having waded through the above account of calculation of results for rings together with the detail given in the references, it is not surprising that the majority of people opt for dumb-bell test pieces. 

ISO 8013 recommends that the test piece is mechanically conditioned by straining 5 times to a higher strain than used in the test between 16 and 48 hours before test, which is intended to remove any irreversible structure. It is then specified that a force shall be applied within 6sec such that an initial strain of 20 2% is realised. The deformation of the test piece is measured after 10 min with further measurements after 10, 100, 1000 min etc. The calculation of results calls for creep increment, creep index and compliance increment after the specified time. Obviously, the strain and time scale could be adjusted to suit individual applications and the creep could be presented graphically as a function of log(time). 

Calculation of Results. By considering the loss of e aq as two psuedo-first-order reactions, namely, a decay by the matrix, m, and decay by the scavenger, s... 

The consecutive steps in speciation analysis are sample collection, sample conservation and storage, elimination of counterfeit samples, extraction/mineral-isation, derivatisation, separation, detection, calibration, calculation of results and evaluation of results [212, 234, 235]. 

Each plot of an analyte in a multilevel or hnear regression calibration model must contain an identifier for that calibration line and the analyte to be determined. The calibration curve should show all calibrating standards mn in any particular assay. In assays containing more than one analyte it will be necessary to interpret all the calibration graphs before the calculation of results. Again, this is an area that is poor for data system as many only offer one line fitting method for all analytes in the run, resulting in compromises. 

Methods for the calculation of results are listed. Often several methods of determining the EC50, LD50, or NOEL are referenced. 

Computers command and phase the electromechanical operation of the analyzer, thus ensuring that all functions are performed uniformly, are repeatable, and are in the correct sequence (e.g., transfer of solutions, placement of proper filters, and regulation and change in speed of rotation). Computer control of operational features of automated equipment, calculation of results, and monitoring of operation contribute to the increased reproducibility of results. These combined features, theoretically at least, allow less-skiUed operators to operate such systems. 

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