calibration  R Documentation 
Defines a calibration
object for the calculation of concentrations
from measurement signals including estimations for the limit of detection
(LOD) and limit of quantification (LOQ) in accordance with DIN 32645 (2008).
The LOD is defined as the lowest quantity of a substance that can be
distinguished from the absence of that substance (blank value) within a
given confidence level (alpha
). The LOQ is defined as the lowest quantity of
a substance that can be quantified/distinguished from another sample given
with respect to a defined confidence level (k
).
calibration( formula, data = NULL, blanks = NULL, weights = NULL, model = "lm", check_assumptions = TRUE, ... ) ## S3 method for class 'calibration' print(x, ...) ## S3 method for class 'calibration' summary(object, ...) ## S3 method for class 'calibration' plot(x, interval = "conf", level = 0.95, ...) lod(object, ...) ## S3 method for class 'calibration' lod(object, blanks = NULL, alpha = 0.01, level = 0.05, ...) loq(object, ...) ## S3 method for class 'calibration' loq( object, blanks = NULL, alpha = 0.01, k = 3, level = 0.05, maxiter = 10, ... )
formula 
model formula providing the recorded signal intensities with
respect to the nominal analyte concentrations in the form of

data 
an optional data frame containing the variables in the model. 
blanks 
a vector of numeric blank values overriding those automatically retrieved from calibration data. 
weights 
an optional character string containing one or more model
variables, for example, in the form of " 
model 
model class to be used for fitting; currently,

check_assumptions 
automatically check for normality and
homoscedasticity of model residuals using 
... 
further arguments passed to the submethod, namely the
respective model environment such as 
x, object 
an object of class ' 
interval 
Type of interval calculation (can be abbreviated); see

level 
tolerance/confidence level; see 
alpha 
error tolerance for the detection limit (critical value). 
k 
relative uncertainty for the limit of quantification
( 
maxiter 
a positive integer specifying the maximum number of iterations to calculate the LOQ. 
If the data
supplied to calibration
contain more than one blank
value, namely measurements with a nominal concentration of or close to zero,
the LOD and LOQ are calculated from the deviation of the blank samples. This
method is called "blank method" according to DIN 32645 (2008) and supposed
to be more accurate than the socalled "calibration method" which will be
used for the estimation of LOD and LOQ when data
does not contain zero
concentration measurements.
calibration
returns an object of class
'calibration
'. print()
calls the function parameters together with the
respective LOD and LOQ. plot()
plots the respective calibration curve
together with the measurement values. summary()
may be used to retrieve
the summary of the underlying model.
Zacharias Steinmetz
Almeida, A. M. D., CastelBranco, M. M., & Falcao, A. C. (2002). Linear regression for calibration lines revisited: weighting schemes for bioanalytical methods. Journal of Chromatography B, 774(2), 215222. doi: 10.1016/S15700232(02)002441.
Currie, L.A. (1999). Nomenclature in evaluation of analytical methods including detection and quantification capabilities: (IUPAC Recommendations 1995). Analytica Chimica Acta 391, 105126.
DIN 32645 (2008). Chemical analysis  Decision limit, detection limit and determination limit under repeatability conditions  Terms, methods, evaluation. Technical standard. Deutsches Institut für Normung, Berlin.
Massart, D.L., Vandeginste, B.G., Buydens, L.M.C., Lewi, P.J., & SmeyersVerbeke, J. (1997). Handbook of chemometrics and qualimetrics: Part A. Elsevier Science Inc.
Other calibration:
din32645
,
icp
,
matrix_effect()
,
neitzel2003
,
weight_select()
data(din32645) din < calibration(Area ~ Conc, data = din32645) din plot(din) summary(din) lod(din) loq(din)
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.