Spanjer's chromatography data were published in Spanjer (1984). The authors studied chromatographic retention characteristics of several chemical compounds. The basic purpose of this type of study is to determine which chemical compounds are present in a chemical mixture. To do this, the mixture is dissolved in a liquid, the eluent or mobile phase. This solution is entered into a vertical glass tube or column packed with solid material, the stationary phase. Different compounds or solutes travel at different speeds through the column, depending both on the phases and the affinity of the solute to these phases. The time it takes to travel through the column is called the retention time, and this differs with phases and solutes. It takes some time for a solute to emerge from the column but there generally is a single-peaked function indicating the amounts of a solute exiting the column over time. The instrument used to measure the relative concentration over time is called a chromatograph. Missing data can occur because some compounds take too long to travel through the column, so that their peaks do not emerge until after the experiment is concluded. Spanjer (1984) used the data set to estimate the missing data themselves. In particular, one may explore the effect of starting solutions, different algorithms, varying numbers of components, and effects of centering as was done in Kroonenberg (2008).
The data contains 21 missing data indicated by -9.99.
|No.||Solutes||Type of monosubstituted compound|
|1.||N-Hexa||35 v/v% methylene chloride in n-hexane|
|2.||Methyl||pure methylene chloride|
A three-way data array X = (x(i,j,k)) has the following form
|-----|i=1 |-----| |i=2 | | |.. | | |.. | |____|i=I=39 |_____| k=K=2 j=1,.,J=3 k=1
The actual data file has the following form:
j=1,.,J=3 |-----|i=1 | |i=2 | |.. k=1 | |.. |_____|i=I=39 |-----|i=1 | |i=2 | |.. k=K=2 | |.. |_____|i=I=39
Thus the first mode (i) is nested in the third mode (k) and there are 39 (Solutes) times 2 (Eluents (Mobile phase)) rows and 3 (Adsorbents (Stationary phase)) columns.
Spanjer did not preprocess these data. For details see Kroonenberg (2008). Applied multiway data analysis. Hoboken NJ: Wiley (Chapters 6 and 7).
[Download the zipped Chromatography Data]