Minimum quantifiable limit

The extraction of the AOT samples consisted of taking a 50-mL subsample and extracting by separatory funnel with hexane and 10% NaCl in water. The cleaned-up and dried hexane extract was then injected onto a gas chromatograph (GC) with an ECD (electron conductivity detector). The minimum quantifiable limit (MQL), or limit of quantification, for the method was 0.002 ug/mL dislodging solution. A typical set of chromatograms can be seen in Figures 1 and 2. 

The development of the experimental procedure then involves the preparation of standard mixtures to prepare a calibration curve, with due care paid to corrections for particle size distribution, background, illuminated volume of sample and preferred orientation. A typical calibration run is shown in Fig. 4.25. Determinations on a series of similar spiked mixtures leads to the calibration curve in Fig. 4.26. Analysis of the resulting data led to the determination of a minimum quantifiable limit of 5 per cent, a working range of 5-50 per cent Form B and an RDS of 16 per cent. The method... 

It is important to point out here that each polymorphic system, indeed each polymorphic modification of polymorphic system must be considered unique and must be individually characterized. For instance, the 5 per cent minimum quantifiable limit for the above system is well above the technical feasibility. Depending on the nature... 

Measured value at LQ (MLQ) (also minimum quantifiable value, IUPAC [1995]) Limit of quantification, LQ... 

One of the most important performance characteristics in residue analysis is certainly the detection capability of a method. Unfortunately, many different definitions with regard to the detection and quantifying capability of an analytical method are found in the literature. Attempts have been made to harmonize the definitions with regard to the limit of detection (LoD) and the limit of quantification (LoQ). For the sake of consistency, here reference is made only to the harmonized definitions of IUPAC and ISO for the detection decision (Lc, critical value), LoD (minimum detectable value) and LoQ (minimum quantifiable value) (45 -47). ISO terminology is given between brackets. 

Depending on the stage of development of a pharmaceutical product, the decision for selecting ICP-AES over an AAS technique may simply be the amount of sample available for a set of analyses. The advent of axial ICP-AES systems, with their increased sensitivity, makes ICP-AES an excellent choice where large amounts of sample are not available. The axial ICP-AES system allows the analyst to use considerably less sample than in the past, while achieving the same detection limits and minimum quantifiable hmits. 

As a rule, the lower the temperature used for equilibration, the fewer artifacts from decomposition of the surfactant clutter the chromatogram. On the other hand, the lower the equilibration temperature, the higher the detection limit for the analyte. Thus the optimal headspace GC conditions are somewhat dependent on the value chosen for minimum quantifiable concentration. Artifacts produced from decomposition of the surfactant include aldehydes and ethylene oxide itself. Some investigators add stabilizers like butylated hydroxytoluene to inhibit decomposition. 

The MDL and practical quantitation limit (PQL) should be appropriate for the objectives of the analysis. MDL refers to the minimum concentration of the compound of interest that can be measured and reported with a specified confidence (99% probability) that the concentration is above zero. The registrants must provide or develop an analytical method for water for the parent pesticide and its degradates that has an MDL of 0.01% of the label application rate (calculated as the average concentration in the top six inches of soil), or 0.05 pgL , whichever is lower. PQL refers to the lowest concentration at which the laboratory can confidently quantify the concentration of the compound of interest. The study authors must report all samples with concentrations above the MDL as detections, including those below the PQL in which the concentration cannot be quantified. In addition, the study authors must provide sample equations to demonstrate how the PQL was calculated. 

Limit of Quantification, (LoQ), sometimes also called limit of quantitation or limit of determination, is the minimum content that can be quantified with a certain confidence. Values below LoQ are reported as less than. 

The Limit of Quantification is the minimum content that can be quantified with a certain confidence... 

Multivariate methods, on the other hand, resolve the major sources by analyzing the entire ambient data matrix. Factor analysis, for example, examines elemental and sample correlations in the ambient data matrix. This analysis yields the minimum number of factors required to reproduce the ambient data matrix, their relative chemical composition and their contribution to the mass variability. A major limitation in common and principal component factor analysis is the abstract nature of the factors and the difficulty these methods have in relating these factors to real world sources. Hopke, et al. (13.14) have improved the methods ability to associate these abstract factors with controllable sources by combining source data from the F matrix, with Malinowski s target transformation factor analysis program. (15) Hopke, et al. (13,14) as well as Klelnman, et al. (10) have used the results of factor analysis along with multiple regression to quantify the source contributions. Their approach is similar to the chemical mass balance approach except they use a least squares fit of the total mass on different filters Instead of a least squares fit of the chemicals on an individual filter. 

Equations (21a,b) allow quantifying the two limiting cases of maximum and minimum coupling range, 1 —> 0 and /> - r. respectively. For arguments < n, the... 

Effect of the face gas velocity (mass transfer limitations). It is well known how these monolithic catalysts work in laminar flow because of the small size of their channels. There are transversal gradients of concentration in them, thus. This effect has been quantify in this research by two ways 1st) Some tests were made with the same gas hourly space-velocity [10,000 h (450 C)] varying the face gas velocity (equivalent to Ae superficial gas velocity in fixed beds) from 28 to 83 cm/s, The monoliths were then cut to different lengths (from 10 to 30 cm). Results on oxidation of EC (1,000 ppm at inlet) are shown in Figure 3 for two BASF catalysts, and indicate some external diffusion control at low face gas velocities. To keep it to a minimum extent, most of further tests were made at the maximum (in this facility) face velocity 83 cm/s. 2nd) Mass transfer limitations in these monoliths have also been studied by the well established procedures in chemical engineering, following the detailed... 

Limit of Detection The lowest amount of analyte in a sample that can be detected but not quantified as an exact value. Also called lower limit of detection, minimum detectable concentration (or dose or value). ... 

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