Detection limit defining

Detection limit (defined as two times the noise level) as minimum detectable quantity is given by ... 

Definition The detection limit defines the smallest flow or the lowest amount of analyte necessary to obtain a signal that can be distinguished from the background noise. The detection limit is valid for one well-specified analyte upon treatment according to a certain analytical protocol. [27-29]... 

We suggest using a new parameter, the minimum reportable concentration, defined as the concentration whose confidence band just includes zero (5.). This parameter is obtained by reducing the value of signal Yo, figure 4, until the band around predicted concentration, Xo, just touches zero. For example, for the determination of iron in water by AAS, (data given in Table III) the detection limit, defined as the concentration at which the... 

Consider a sample that contains analyte at the detection limit defined in Figure 5-2. Explain the following statements There is approximately a 1% chance of falsely concluding that a sample containing no analyte contains analyte above the detection limit. There is a 50% chance of concluding that a sample that really contains analyte at the detection limit does not contain analyte above the detection limit. 

The inhibition and the subsequent signal detection were performed in two different solutions. First the pesticide solution was added and then after 10 min (incubation time) the sensor was moved into a new buffer solution where the substrate (5mmoll 1 acetylthiocholine) was injected and the signal measured. This procedure is particularly suitable when a complex matrix, which could pose problems for the direct measurement of thiocholine oxidation, is used. The analytical characteristics of pesticide determination in standard solutions were then evaluated. Detection limits, defined in this work as the concentrations giving an inhibition of 20%, were 30 and 10 ppb for aldicarb and paraoxon, respectively. By increasing the incubation time up to 30 min, an increase in the degree of inhibition could be observed and lower detection limits both for Aldicarb (5 ppb) and Paraoxon (3 ppb) were achieved. 

The detection limit, defined as the smallest concentration level of the element that can be measured, takes into consideration both the signal intensity and the baseline noise. It is defined as equal to the concentration level of the element to be analysed for which the absorbance has a value equal to six times that of the standard deviation of at least ten values measured on the blank test solution. 

The detection limit, defined as the element concentration corresponding to three times the standard deviation of the blank, is calculated to about 4 ng for antimony and tin and 2 ng for bismuth. When 400 m of air are fUtered and a 2 ml aliquot of the initial 50 ml sample solution is analyzed, practical detection limits are obtained of 0 25 ng m" for antimony and tin and 0.13 ng m" for bismuth. 

It is important to note that with the advent of highly sensitive immunoassays for the measurement of serum and urine (3-hCG concentrations, it has been occasionally observed that postmenopausal women have slightly elevated p-hCG concentrations (typically >5 but <25IU/L). These results may cause confusion when the concentrations are above the detection limit defined for a positive pregnancy test. Although this phenomenon is not associated with pregnancy, these results are not false positives as they are routinely confirmed by alternate methods. 

Determination of methyl paraoxon can be realized in the range of 10"8 -10 6 mol/L. The detection limit, defined as the concentration of pesticide that produce an inhibition percentage of 10% of the AChE activity correspond to a concentration of 5 10 9 mol/L methyl paraoxon. 

Using this method of analysis, the detection limits (defined as above) for glutamate and aspartate are 0.008 pM, or 67 ftnol on the column. For comparison, basal concentrations of glutamate and aspartate m rat striatum dialysates are 1.085 0.129 pM and 0.080 0.013 pM, respectively. 

Thus, a broad range of sometimes complementary analytical techniques is available at present for the characterisation of the various PAH/POM emissions. For standardisation purposes, candidate methods must be tested extensively in a collaborative exercise to determine and evaluate repeatability, reproducibility and recovery criteria before final definition and approval. (Recently, the method detection limit, defined as the concentration which can be detected at a specific confidence level, was proposed as one criterion for assessing the performance of an analytical method (18)). 

The minimum detectable limit defines the concentration level above which it is possible to say with confidence that the element is present. In practical analytical problems one finds that detection is necessary but seldom sufficient. Reporting detection usually stimulates the question About how much Hence, it becomes necessary to define the concentration level at which it is possible to say roughly how much is present. This concentration is called the minimum analyzable limit. Here again, the precise choice of numbers to define the limit is somewhat arbitrary. Frequently the analyzable limit is defined as the concentration that can be measured with a percent standard deviation of 10%. That is,... 

The detection limit defined by the DIN standard is the characteristic value of a measurement process which decides whether the measurement process satisfies a specific requirement, such as the detection of 0.1 Bq/1. 

Phosphomolybdenum blue—batch method Visible photometry MRP 10 0.4 0.32 0.013 100 mm cell Lower detection limit possible detection limit defined [173]... 

The detection limit, defined as the main flow rate of element entering the plasma required to produce a signal to noise ratio of two as listed below together with the selectivity Mercury 253,7nm, detection limit Ipg/s, selectivity 9,1 x 10, ... 

Detection limit Defines the smallest concentration that can be measured. This is also referred to as the Lower Limit of detection (LOD). This is not to be confused with sensitivity... 

Instrument detection limit, defined statistically as a measure for the potential instrument sensitivity at the 99% confidence level from the area precision (RSD%) of a series of measurements, applied in cases a S/N cannot be calculated due to the absence of a suitable noise band in modern digitally filtered MS systems. The IDL does not inform about the lowest detectable concentration LOD. 

The detection limit metric, as used here, is different from the sensitivity metric. Unlike sensitivity, which deals only with absolute signal, detection limits consider signal-to-noise ratio (S/N). Detection limits also consider the entire analytical method including sample extraction efficiencies and injection volumes in addition to the response characteristics and noise levels of the mass spectrometer signal. Detection limits are therefore analytically more relevant than sensitivity. Sensitivity measurements allow one to estimate the theoretical limits for the quantity of a compound that can be detected, whereas detection limits define what can actually be achieved in a practical setting to provide a meaningful result toward the solution of some application of mass spectrometry. 

Detection limit defined as the concentration of gas whose maximum absorption peak lies 3 a above the baseline noise. 

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