Calculation of Partition Coefficients

In order to calculate partition coefficients you will first have to search for the chemicals of interest. As a second step you have to select compounds, which should be used to calculate the respective partitioning coefficients. If no compound of your query result is selected, all chemicals will be included in the calculations. In the last step you have to select the partition systems of interest. Only if at least one chemical and one system has been selected, a button will appear that enables you to calculate partition coefficients for all chemicals and all selected systems.

Calculation of the Extraction Efficiency

In order to calculate the fraction of an analyte that is extracted, one first has to search and select the analyte(s) in the database. If no chemical of the query result is specified by clicking on it, all chemicals returned in the query will be included in the calculations. Next, one has to select all solvents of interest from the list shown in the window. Finally one enters the volumes of the water sample to be extracted. The fraction of analyte in the solvent can be calculated for a given volume of solvent or for different solvent volumes. It is also possible to calculate the respective volume of solvent for a defined fraction of analyte in the solvent or to include a two-step extraction. Additional components in the water phase such as salts (salting-out), proteins and lipids, and organic matter can be considered in the calculations in any combination.

Biopartitioning

In order to calculate the biopartitioning of the analyte one first has to search and select the analyte(s) in the data base. If no chemical of the query result is selected, all chemicals will be included in the calculations. Next one has to enter the composition of the organism in terms of volume percentages of all components (serum albumin, muscle proteins, storage lipids, phospholipids and water).

Freundlich Koc

Non-linear sorption isotherms for soil organic carbon/water partitioning can be described by a Freundlich isotherm. The calculated partition coefficient from the respective ppLFER equation is only valid for aqueous concentrations in the range of 0.03 mmol/L. Often the aqueous concentrations are different to this value. For these concentrations we offer a calculation tool based on the Freundlich isotherm.

Thermodesorption

In order to trap an analyte quantitatively from air to a sorbent the type and amount of sorbent that is used has to be adjusted to the sampling temperature and volume as well as the type of analyte in order to avoid breakthrough. In the subsequent desorption step, temperature and gas volume have to be adjusted to the type and amount of sorbent and the type of analyte. All this can be planned ahead provided that the sorption constants of the analyte on potential sorbents are known as a function of temperature - information that is contained in our database. Hence, we provide tools to calculate a) the sorbent mass required for quantitative trapping, b) the temperature required for quantitative desorption into a specified gas volume and c) as a general information, the volume of gas per gram sorbent at which 50% of the analyte will break through a sorbent column, BTV50% (for 4 different sorbents) at the specified temperature.

Calculation of the passive Caco-2 permeability

In order to calculate the membrane permeability you will first have to search for the chemicals of interest. As a second step you have to enter some experimental details: we recommend that you enter the total thickness of the unstirred water layers on both sides of the cell layer; alternatively you can also enter the agitation of the assay. In the exported spread sheet you have to specify the percentage of the neutral species of each chemical in the calculation. The default value is 100% (for non-ionizable chemicals). If you are interested in acids or bases, then the respective number for the percentage of the neutral species has to be entered in the exported spread sheet and all subsequent calculations will use this fractionation information. The calculated permeability refers to the total concentration of the chemical, assuming that the ionic species does participate in the permeation through the unstirred water layer and the paracellular pathway but not to the transport through the membrane itself.

Cfree

In order to calculate the freely dissolved fraction or concentration of a solute one first has to search (and select) the solute(s) in the database. Subsequently you have to decide between different options: Option1 calculates the freely dissolved concentration/fraction in plasma. Option 2 calculates the freely dissolved concentration/fraction in a selection of cellular assays. Here you must select a specific combination of medium, serum and cell line from a list. The differences between the different options happen to be rather small, so that you might chose any selection to still receive a good estimate for any assay that does not match the components in the list. Also, the cell number is of little influence so that any rough estimation will do. Option 3: Here you can specify any solution/suspension for which you want to calculate Cfree. It is important to note that all results for Cfree only refer to neutral species. Cfree for ionic species or ionizable chemicals cannot be calculated with these tools.

Preconcentration in a gas stream

With this tool one can calculate the percentual loss of analyte, that occurs during preconcentration of a solvent extract with nitrogen at 25°C. Again one first has to search for the analyte in the database. Among the results one has to select one for which all descriptors are present. Afterwards one can go to the blow-down menu and select the type of solvent and the volumina before and after blow-down.

Search for neutral chemicals








Source:

Search for partition systems

most frequently used

Bio Materials





Technical Sorbents



carbonaceous sorbents

Solvent water


Water



Calculate the biopartitioning



volume %
volume %
volume %
volume %
volume %
volume %
* muscle protein is pure muscle protein without lipids

** carbohydrates, minerals ...
** this is not accounted for as a partitioning phase

Calculate the sorbed concentration


mmol/L

Calculate the extraction efficiencies

NameId
acetophenone7
aniline8
benzene9
benzonitrile10
bromobenzene11
butane13
butan-1-ol12
butyl acetate14
carbondisulfide15
chlorobenzene17
chloroform16
cyclohexane18
decan-1-ol19
dibuthylether20
dibutylether21
dichloromethane22
diethylether23
diisopropylether24
ethyl acetate25
ethylbenzene26
fluorobenzene27
heptan-1-ol28
hexan-1-ol29
iodobenzene30
isobutanol31
isooctane32
isopropylmyristate33
methylcyclohexane34
methylisobutylketone35
n-decane36
n-dodecane37
n-heptane38
n-hexadecane39
n-hexane40
nitrobenzene41
N-methylpyrrolidinone42
n-octane43
nonan-1-ol44
n-undecane45
octanol3
oleylalcohol47
olive oil48
o-nitrophenyloctylether49
pentane51
pentan-1-ol50
perfluoro-hexan, -heptane, -octane52
PGDP53
tetrachloromethane54
toluene55
trichloromethane57
triolein58
1-chlorobutane2
1,2-dichloroethane1
2-methyl-1-propanol4
2-methyl-2-propanol5
3-methyl-1-butanol6

Calculate the fraction of solute in the solvent for a given solvent volume

mL
mL

Calculate the fraction of solute in the solvent for various solvent volumes

mL
mL
mL

Calculate the solvent volume for a given fraction of solute in the solvent

mL
%


Water contains:


Salts

mol/L

Proteins and lipids

mL
mL
mg
mg
%
%
Equations for serum albumin and storage lipids are applied

Organic matter

mg
mg



Calculate optimal parameters for thermodesorption

L
°C
mL g
°C

Calculate the maximal loss of solute during solvent blow down with nitrogen

mL
µL

Calculate the permeability through a Caco-2 monolayer

The fraction of neutral species at experimental pH can be entered in the exported excel sheet.
µm
rpm

Calculate the concentration of freely dissolved analyte
ONLY FOR NEUTRAL MOLECULES !!

Option 1: Cfree in plasma

Option 2: Often used assays

µL
%
%

Option 3: Custom made assay

mL
mL
mL
mg
mg
%
%

Please cite this database as:
Ulrich, N., Endo, S., Brown, T.N., Watanabe, N., Bronner, G., Abraham, M.H., Goss, K.-U., UFZ-LSER database v 3.2.1 [Internet], Leipzig, Germany, Helmholtz Centre for Environmental Research-UFZ. 2017 [accessed on 19.04.2024]. Available from http://www.ufz.de/lserd

Citation LSERD Terms of use

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Only valid for neutral chemicals. For more details about the domain of applicability for each descriptor see Excel Export.

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