Linear precision

The validation parameters of the method such as linearity, precision, accuracy, specificity and robustness were good, therefore, the method has been proposed for commercial control laboratories [148]. 

The linearity of the method is demonstrated using 3-5 concentration levels. For APIs, the correlation coefficient should be greater than 0.999. The range is derived from linearity, precision, and accuracy studies and should be established based on the intended application of the method. 

HPLC methods can usually be transferred without many modifications, since most commercially available HPLC instruments behave similarly. This is certainly true when the columns applied have a similar selectivity. One adaptation, sometimes needed, concerns the gradient profiles, because of different instrumental or pump dead-volumes. However, larger differences exist between CE instruments, e.g., in hydrodynamic injection procedures, in minimum capillary lengths, in capillary distances to the detector, in cooling mechanisms, and in the injected sample volumes. This makes CE method transfers more difficult. Since robustness tests are performed to avoid transfer problems, these tests seem even more important for CE method validation, than for HPLC method validation. However, in the literature, a robustness test only rarely is included in the validation process of a CE method, and usually only linearity, precision, accuracy, specificity, range, and/or limits of detection and quantification are evaluated. Robustness tests are described in references 20 and 59-92. Given the instrumental transfer problems for CE methods, a robustness test guaranteeing to some extent a successful transfer should include besides the instrument on which the method was developed at least one alternative instrument. 

In a recent study, Mirza et al. have pointed out that despite the obvious advantages, fiber-based dissolution studies are not yet implemented in industry. They have validated a fiber-optic based dissolution test for linearity, precision, accuracy, specificity and robusmess, with excellent results. 

P33 Analyses wereper/ormed on a gas chromatograph equipped with an electron capture detector (ECD) and a gas chromatograph coupled to a mass-selective detector working in mass spectrometry-mass spectrometry (MS-MS) mode, to achieve better limits of detection and selectivity. The proposed method yields high sensitivity, good linearity, precision, and accuracy. (From Dellinger et ah, 2001)... 

Schubert et al. [72] developed and validated a liquid chromatographic method for the determination of omeprazole in powder for injection and in pellets. The analyses were performed at room temperature on a reversed-phase Ci8 column of 250 mm x 4.6 mm (5 /im). The mobile phase, composed of methanol-water (90 10) was pumped at a constant flow-rate of 1.5 ml/min. Detection was performed on a UV detector at 301 nm. The method was validated in terms of linearity, precision, accuracy, and ruggedness. 

A sensitive reverse-phase HPLC method has been developed for the analysis of etodolac in tablet formulation [22]. The chromatographic separation was achieved using a reverse-phase Cu column, having dimensions of 3.3 cm x 0.46 cm i.d. (3 pm particles) and which was maintained at 30°C. The mobile phase consisted of pH 6.0 phosphate buffer / methanol (60 40 v/v), and was eluted at 1 mL/min. Analyte detection was effected on the basis of UV detection at 230 nm. Diazepam was used as an internal standard. The sample preparation entailed grinding the etodolac tablets, followed by extraction with methanol (using sonication). A retention time of 1.46 min was obtained for etodolac under these conditions, and the method was found to be linear, precise, and accurate over the concentration range of 0.01 to 0.1 mg/mL. 

The work of Mosko [116] is important in that he is one of the few workers who have given serious consideration to the determination of nitrite in water. His paper is concerned with the determination of chloride, sulphate, nitrate, nitrite, orthophosphate, fluoride and bromide in industrial effluents, waste water and cooling water. Two types of analytical columns were evaluated (standard anion and fast run series). Chromatographic conditions, sample pretreatment and the results of interference, sensitivity, linearity, precision, comparative and recovery studies are described. The standard column provided separation capabilities which permitted the determination of all seven anions. The fast run column could not be used for samples containing nitrite or bromide owing to resolution problems. 

Method validation includes determination of performance characteristics such as selectivity (which determines accuracy), linearity, precision, and sensitivity (limit of detection). This work evaluated linearity, precision, and sensitivity for specific CZE separation conditions selectivity was reported previously (15). Factors that contribute to assay imprecision by affecting peak shape (such as the pH of the mobile phase) or migration velocity (pH effects on the electrophoretic velocity) were evaluated also. 

Sodium, potassium and chloride sensors were evaluated using undiluted serum specimens with no sample pretreatment of any kind. The performance data set, summarized by Table II, comprises a minimum of 8 sensors and 60 samples. The bicarbonate assays were performed separately on serum specimens buffered at pH 9.0. Clinical efficacy is normally judged by the response linearity, precision and... 

The same authors also applied capillary electrophoresis to the study of benazepril hydrochloride and several angiotensin-converting enzyme inhibitors [43]. Separation of the compounds was performed by means of two phosphate buffers (each 0.1 M) at pH 7 and 6.25, respectively [42], Due to the highest selectivity of the first mentioned running buffer, the same system has been applied for the quantification of benazepril and other compounds in their corresponding pharmaceutical formulations. It was found that the possibility of simultaneous identification and quantification of the active ingredient in the finished products was especially attractive, and that excipients do not adversely affect the results. This article deals with the validation of some parameters of the quantitative analysis, namely linearity, precision, accuracy, and robustness [43],... 

Addition of excess of hydrogen, on the other hand, served to raise the ignition temperature 2 steadily, with practically linear precision, so that the temperature of ignition m the presence of. molecules of hydrogen, within the limits a =0 and 13, could be calculated from the expression... 

Urine sufficient number of intervals to characterize the rate and extent of urinary elimination of the test article 0-2, 2-4, 4-8, 8-12, and 12-24 hours for intravenous and oral doses Validated assay for plasma and urine specimens from rats to be cross-species validated for specificity, sensitivity, linearity, precision, and accuracy... 

Limit of detection, limit of quantification, selectivity, linearity, precision, accuracy, ruggedness. 

Zhang et al. [43] developed and validated a stability indicating HPLC method for the determination of lornoxicam in pharmaceutical formulation. The isocratic procedure was performed in Shimadzu ODS (4.6 mm x 15 cm, 5 pm) column maintained at 25 °C. The mobile phase was degassed mixture of sodium acetate (0.05 mol/L, pH 5.8) and methanol (55 45). The flow rate was 1 ml/min and detection at 290 nm. Selectivity, specificity, linearity, precision, accuracy, and robustness were evaluated to validate the analytical method. Forced degradation studies were performed to provide an indication of the stability-indicating capacity. The stability indicating method for lornoxicam in the injectable dosage was developed and validated. The method can be considered for routine analysis and quality control of lornoxicam in injectable formulation. 

Bartolucci et al. [33] compared qnantitative data from a triple-qnadmpole and an ion-trap instmment. Both instmments were applicable in residue analysis. The overall performance of the triple-qnadmpole instmment was superior in terms of linearity, precision, and sensitivity. 

E692 Wilwerding, S., Nipper, H., Bozek, S., Teflf, R., Lynch, K. and McClellan, G. (1990). Evaluation of automated CK-MB methods for linearity, precision and accuracy compared to agarose gel electrophoresis in a CCU population. Clin. Chem. 36, 1136, Abstr. 836. 

It is tempting to say that the parameter values of new vertices are obtained by applying the same process to them as to the coordinates. However, this is dependent on a subtlety called linear precision which will be elaborated later in chapter 20 below. 

Similarity is seen between human and animal health products in analytical testing conducted to assure the quality attributes of the final product. The validation of these assays is identical in that linearity, precision, accuracy, robustness, and reproducibility are aU required. Two examples of analytical areas that may differ include stability and in vitro drug testing. 

In order to use TLC as a quantitative method of analysis, it is essential to quantify the spots (Figures 5.1 and 5.6), along with definitions for all of the usual parameters (specificity, range of the domain of linearity, precision, etc.). This is done by placing the plate under the lens of a densitometer (or scanner) that can measure either absorption or fluorescence at one or several wavelengths. This instrument produces a pseudo-chromatogram that contains peaks whose areas can be measured. In fact it is actually an isochronic image of the separation at the final instant. In TLC a spot is usually detectable if it corresponds at least to a few ng of a compound UV absorbent. 

Analytical characteristics. The proposed RRS method was studied for linearity, precision, and sensitivity. Under the optimum conditions, a linear relationship between BSA concentration and enhanced scattering intensity was obtained over the range of 0-1.4 pg/mL, with a regression equation of A/= -39.17 + 2.661 (pg /L) and correlation coefficient (r) of 0.9966. The detection limit of BSA was found to be 2.04 x 10 9g/mL according to 11 parallel determinations of the blank solution. Applications. A milk sample was diluted to 100 mL with water, and then determined by the proposed method. The recovery rates of the method were 96.2 % and 102.8 % RSD was 3.08 and 0.93 that indicated the results were satisfactory. 

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