### Author Topic: Specifying Unanalyzed Elements For a Proper Matrix Correction  (Read 17949 times)

#### John Donovan

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##### Specifying Unanalyzed Elements For a Proper Matrix Correction
« on: October 24, 2013, 12:21:40 pm »
In order that the measured intensities get properly corrected for matrix effects we need to know the composition of the sample (and the standard).

For standards this is easy because of course we already know the composition of the standard (or it wouldn't be a standard!). So based on the "published" standard composition from the Standard.mdb database we calculate the physics relative to the theoretical pure element. This is called the standard k-factor and is calculated as seen here for each element.

If the standard is a pure element, then the concentration is 1.0 and the matrix correction is 1.0 and therefore the std k-factor is 1.0. In any case the std k-factor is included in the calculation of the unknown concentration by iteratively determining the unknown composition starting with the "1st approximation" where the ratio of intensities (Iunk/Istd) is assumed to be equal to the ratio of the concentrations (Cunk/Cstd) and calculated as seen here:

What does all this mean?  It means that we need to know the correct composition of the unknown in order to correctly calculate the concentration of each measured element. Therefore, if some elements are *not* measured, for example, geologists often (but not always) assumed formula stoichiometry for including oxygen in the matrix correction. Obviously in the case of variable oxidation states, e.g., FeO vs. Fe2O3, replacement of stoichiometric oxygen by halogens, and glasses containing significant H2O, there is some ambiguity in the matrix chemistry which can significantly affect the matrix correction for measured elements as seen in these posts:

http://probesoftware.com/smf/index.php?topic=62.msg235#msg235

http://probesoftware.com/smf/index.php?topic=81.msg292#msg292

In practice we can sometimes "get away" with a simplification of the matrix assumption, for a quite amazing example we might try measuring only U, Th, Pb (and Y and La for the interference correction on Pb Ma) and assuming CePO4 by difference in the matrix correction of the mineral monazite. Surprisingly this assumption works to an extent that is quite impressive, though obviously  one cannot assume that this simplification of the matrix composition is accurate enough without careful testing both ways.

However, it is not uncommon that if the element in question does not cause an interference and is not especially critical in the matrix correction (run a model in CalcZAF and check the absorption correction!), we can simply specify the element as an "unanalyzed" element. In CalcZAF and Probe for EPMA this means that the element does not have an x-ray line specified as shown here in the Elements/Cations dialog from the Analyze! or Acquire! windows:

Once the element is entered as an "unanalyzed" element, we can use the Specified Concentrations (or Calculation Options) dialog from the Analyze! window to enter element concentrations by "specification" as seen here:

This dialog, seen below, has many options for entering elements that are unanalyzed, or even measured by another technique:

The simplest method is to click on a row in the element grid containing a specified (or unanalyzed) element and enter the specified concentration in elemental or oxide weight percent.  One can also specify by formula, by standard composition (useful when analyzing a standard as an unknown), by text file input (see User's Reference manual for details), or by the (one time) analysis of another sample or by the analysis of a sample just prior to the analysis of the currently selected sample. Whew!

Other options for matrix specification are available in the Calculation Options dialog from the Analyze! window which we turn to next.
« Last Edit: December 16, 2013, 01:51:12 pm by John Donovan »
John J. Donovan, Pres.
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#### John Donovan

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##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #1 on: October 24, 2013, 12:29:18 pm »
From the Analyze! window we can also select the Calculation Options dialog and then we see this:

Note that in this example we have selected calculate oxygen by formula stoichiometry (the oxygen stoichiometry can be changed in the Elements/Cations dialog), element by difference is Ce and calculate P by stoichiometry to the stoichiometrc oxygen.

This allows us to specify the formula CePO4 by difference from the measured elements expressed as oxides without measuring Ce or P or O.

There are many variations on this method, for example in carbonates we might specify oxygen by stoichiometry and carbon by stoichiometry (0.333 to 1) to the stoichiometric (calculated) oxygen to obtain CO3 by stoichiometry to the measured cations (usually Ca, Mg, Fe, Mn, etc).
John J. Donovan, Pres.
(541) 343-3400

"Not Absolutely Certain, Yet Reliable"

#### Probeman

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##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #2 on: December 16, 2013, 12:52:50 pm »
Here's an example of a monazite calculation that I've done where Ce2O3 was calculated by difference and P2O5 was calculated by stoichiometry to the calculated (stoichiometric) oxygen using the settings in the Calculation Options dialog shown in the previous post:

Un    8 Allaz-3
TakeOff = 40.0  KiloVolt = 15.0  Beam Current = 50.0  Beam Size =    5
(Magnification (analytical) =  40000),        Beam Mode = Analog  Spot
(Magnification (default) =      400, Magnification (imaging) =    800)
Image Shift (X,Y):                                          .00,   .00
Number of Data Lines:   9             Number of 'Good' Data Lines:   9
First/Last Date-Time: 10/30/2013 12:04:35 PM to 10/30/2013 01:02:35 PM
WARNING- Using Exponential Off-Peak correction for th ma

Average Total Oxygen:       27.194     Average Total Weight%:  100.000
Average Calculated Oxygen:  27.194     Average Atomic Number:   39.773
Average Excess Oxygen:        .000     Average Atomic Weight:   39.299
Average ZAF Iteration:       11.00     Average Quant Iterate:     3.00

Oxygen Calculated by Cation Stoichiometry and Included in the Matrix Correction
Element Ce is Calculated by Difference from 100%
Element P is Calculated  .25 Atoms Relative To 1.0 Atom of Oxygen

Un    8 Allaz-3, Results in Elemental Weight Percents

ELEM:        U      Th      Pb       Y      La      Ce       P       O
TYPE:     ANAL    ANAL    ANAL    ANAL    ANAL    DIFF    STOI    CALC
BGDS:      LIN     EXP     LIN     LIN     LIN
TIME:   200.00  200.00  200.00  120.00  120.00
BEAM:    49.82   49.82   49.82   49.82   49.82

ELEM:        U      Th      Pb       Y      La      Ce       P       O   SUM
219    .472   3.341    .567   1.826   9.508  43.870  13.179  27.237 100.000
220    .446   3.334    .524   1.638   9.721  43.952  13.169  27.216 100.000
221    .237   3.150    .424   1.054   9.937  44.893  13.142  27.162 100.000
222    .510   3.582    .581   1.695   9.716  43.555  13.161  27.200 100.000
223    .445   3.923    .599   1.587   9.413  43.725  13.144  27.165 100.000
224    .512   3.290    .558   1.789   9.884  43.557  13.177  27.234 100.000
225    .515   3.329    .573   1.865   9.354  43.944  13.180  27.240 100.000
226    .125   4.790    .400   1.349   8.802  44.278  13.126  27.129 100.000
227    .446   3.816    .595   1.555   9.514  43.764  13.145  27.167 100.000

AVER:     .412   3.617    .536   1.595   9.539  43.949  13.158  27.194 100.000
SDEV:     .137    .509    .074    .257    .342    .418    .019    .040    .000
SERR:     .046    .170    .025    .086    .114    .139    .006    .013
%RSD:    33.28   14.08   13.75   16.13    3.59     .95     .15     .15
STDS:       15      18     386    1016     836       0       0       0

STKF:    .8725   .8707   .6861   .4480   .6591   .0000   .0000   .0000
STCT:   137.33   44.30  140.31   38.76   33.08     .00     .00     .00

UNKF:    .0035   .0302   .0041   .0116   .0829   .0000   .0000   .0000
UNCT:      .55    1.54     .84    1.00    4.16     .00     .00     .00
UNBG:      .77     .26     .54     .13     .19     .00     .00     .00

ZCOR:   1.1794  1.1961  1.3069  1.3748  1.1510   .0000   .0000   .0000
KRAW:    .0040   .0347   .0060   .0259   .1257   .0000   .0000   .0000
PKBG:     1.71    6.87    2.56    8.82   23.27     .00     .00     .00
INT%:   -14.77    ----   -2.38    ----    ----    ----    ----    ----

Un    8 Allaz-3, Results in Oxide Weight Percents

ELEM:      UO2    ThO2     PbO    Y2O3   La2O3   Ce2O3    P2O5       O   SUM
219    .536   3.802    .611   2.319  11.151  51.384  30.198    .000 100.000
220    .506   3.794    .564   2.080  11.401  51.480  30.175    .000 100.000
221    .268   3.585    .457   1.339  11.654  52.582  30.115    .000 100.000
222    .578   4.076    .626   2.153  11.395  51.015  30.157    .000 100.000
223    .504   4.464    .645   2.015  11.040  51.214  30.118    .000 100.000
224    .580   3.744    .601   2.272  11.591  51.018  30.194    .000 100.000
225    .584   3.788    .617   2.368  10.970  51.471  30.201    .000 100.000
226    .142   5.451    .431   1.713  10.323  51.863  30.078    .000 100.000
227    .505   4.342    .641   1.974  11.157  51.260  30.120    .000 100.000

AVER:     .467   4.116    .577   2.026  11.187  51.476  30.151    .000 100.000
SDEV:     .156    .580    .079    .327    .401    .490    .045    .000    .000
SERR:     .052    .193    .026    .109    .134    .163    .015    .000
%RSD:    33.28   14.08   13.75   16.13    3.59     .95     .15  375.00
STDS:       15      18     386    1016     836       0       0       0

Un    8 Allaz-3, Results in Millions of Years Ago, EPMA Age (from U, Th, Pb)

U WT%  Th WT%  Pb WT%   U PPM  Th PPM  Pb PPM Age[My] Calc Pb %Pb(Th)  %Pb(U)
219 .472289 3.34109 .567045 4722.89 33410.9 5670.45 2323.00 5670.27 64.3415 35.6635
220 .446398 3.33429 .523589 4463.98 33342.9 5235.90 2208.20 5236.10 65.9074 34.0874
221 .236642 3.15039 .424494 2366.42 31503.9 4244.94 2226.00 4245.02 77.4650 22.5299
222 .509558 3.58221 .581436 5095.58 35822.1 5814.36 2231.20 5814.52 64.4655 35.5293
223 .444676 3.92270 .598909 4446.76 39227.0 5989.09 2258.10 5989.38 69.4054 30.5896
224 .511685 3.28988 .557768 5116.85 32898.8 5577.68 2252.20 5577.78 62.3314 37.6634
225 .515049 3.32893 .572963 5150.49 33289.3 5729.63 2285.30 5729.68 62.3537 37.6412
226 .124814 4.79049 .399875 1248.14 47904.9 3998.75 1650.30 3998.89 91.3724 8.62120
227 .445556 3.81612 .594983 4455.56 38161.2 5949.83 2281.40 5949.84 68.7099 31.2850

AVER:  .411852 3.61734 .535674 4118.52 36173.4 5356.74 2190.63 5356.83 69.5947 30.4012
SDEV:  .137073 .509306 .073673 1370.73 5093.06 736.728 205.618 736.721 9.41884 9.41990

« Last Edit: December 16, 2013, 12:58:49 pm by Probeman »
The only stupid question is the one not asked!

#### Probeman

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##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #3 on: December 16, 2013, 01:04:34 pm »
Here's another one: turquoise, which has the ideal formula CuAl6(PO4)4(OH)8 4(H2O).  The Calculation Options dialog looks like this:

Since the ratio of H to Al is 16 to 6, that is 2.666 and this gives the following results

Un    5 Turquoise matrix3
TakeOff = 40.0  KiloVolt = 15.0  Beam Current = 30.0  Beam Size =   20
(Magnification (analytical) =  40000),        Beam Mode = Analog  Spot
(Magnification (default) =      400, Magnification (imaging) =   2797)
Image Shift (X,Y):                                          .00,   .00
Number of Data Lines:   9             Number of 'Good' Data Lines:   6
First/Last Date-Time: 11/20/2013 03:51:02 PM to 11/20/2013 04:22:23 PM
WARNING- Using Exponential Off-Peak correction for p ka
WARNING- Using Slope-Lo Off-Peak correction for ba la
WARNING- Using Exponential Off-Peak correction for si ka
WARNING- Using Time Dependent Intensity (TDI) Element Correction

Average Total Oxygen:       55.067     Average Total Weight%:   99.890
Average Calculated Oxygen:  55.067     Average Atomic Number:   11.402
Average Excess Oxygen:        .000     Average Atomic Weight:   14.468
Average Charge Balance:       .005     Fe+ Atomic Charge:        2.000
Average ZAF Iteration:        3.00     Average Quant Iterate:     3.00

Oxygen Calculated by Cation Stoichiometry and Included in the Matrix Correction
Element H is Calculated  2.666 Atoms Relative To 1.0 Atom of Al

Un    5 Turquoise matrix3, Results in Elemental Weight Percents

ELEM:       Na       P      Ca      Al       K      Fe      Cu       S      Ba      Si       H       O
TYPE:     ANAL    ANAL    ANAL    ANAL    ANAL    ANAL    ANAL    ANAL    ANAL    ANAL    RELA    CALC
BGDS:      LIN     EXP     LIN     LIN     LIN     LIN     LIN     LIN    S-Lo     EXP
TIME:    60.00   60.00   60.00   60.00   60.00   60.00   60.00   60.00   60.00   60.00
BEAM:    30.02   30.02   30.02   30.02   30.02   30.02   30.02   30.02   30.02   30.02

ELEM:       Na       P      Ca      Al       K      Fe      Cu       S      Ba      Si       H       O   SUM
137    .007  13.984    .007  21.165    .061    .259   6.374    .240    .084    .015   2.108  54.469  98.775
140   -.005  14.102    .008  21.078    .067    .289   6.501    .241    .066    .016   2.099  54.612  99.074
141    .004  14.246    .006  21.467    .061    .271   6.770    .234    .062    .019   2.138  55.355 100.633
142   -.001  14.404    .005  21.356    .081    .238   6.673    .216    .039    .013   2.127  55.515 100.664
143   -.009  14.583    .003  21.192    .065    .268   6.559    .221    .053    .018   2.111  55.700 100.764
144    .001  14.177    .012  21.088    .069    .301   6.644    .227    .042    .019   2.100  54.749  99.429

AVER:    -.001  14.250    .007  21.224    .067    .271   6.587    .230    .058    .017   2.114  55.067  99.890
SDEV:     .006    .216    .003    .155    .007    .022    .140    .010    .017    .002    .015    .520    .898
SERR:     .002    .088    .001    .063    .003    .009    .057    .004    .007    .001    .006    .212
%RSD:  -834.06    1.51   44.38     .73   10.91    8.26    2.12    4.53   29.36   14.98     .73     .94
STDS:      336     285     285     336     336     395    1124     327     835     336       0       0

STKF:    .0735   .1599   .3596   .1331   .0409   .6779   .2439   .2207   .7430   .1500   .0000   .0000
STCT:    72.02  276.07  585.58  256.36   29.05  479.39  154.24  192.18  272.78  259.24     .00     .00

UNKF:    .0000   .1087   .0001   .1545   .0006   .0023   .0517   .0018   .0004   .0001   .0000   .0000
UNCT:      .00  187.63     .10  297.46     .41    1.62   32.68    1.56     .15     .20     .00     .00
UNBG:      .33    1.28     .88     .82     .36     .67    1.22     .18     .87     .83     .00     .00

ZCOR:   2.0716  1.3112  1.1184  1.3741  1.1633  1.1845  1.2744  1.2824  1.3769  1.4007   .0000   .0000
KRAW:    .0000   .6797   .0002  1.1603   .0141   .0034   .2119   .0081   .0006   .0008   .0000   .0000
PKBG:      .99  147.55    1.12  366.70    2.15    3.42   27.70    9.80    1.18    1.25     .00     .00
INT%:     -.43    ----    ----     .00    ----    ----    ----    ----  -51.65    ----    ----    ----

TDI%:    -.916  -1.846    .068    ----   2.184  -5.326    ----    ----    ----    ----    ----    ----
DEV%:      5.1      .4     3.9    ----     3.9     2.6    ----    ----    ----    ----    ----    ----
TDIF:   LINEAR  QUADRA  LINEAR    ----  LINEAR  LINEAR    ----    ----    ----    ----    ----    ----
TDIT:    75.00   76.17   75.33    ----   77.00   75.83    ----    ----    ----    ----    ----    ----
TDII:     .332    188.    .974    ----    .778    2.24    ----    ----    ----    ----    ----    ----

Un    5 Turquoise matrix3, Results in Oxide Weight Percents

ELEM:       Na     PO4      Ca      Al       K      Fe      Cu     SO4      Ba      Si    H4O3       O   SUM
137    .007  42.880    .007  21.165    .061    .259   6.374    .718    .084    .015  27.203    .000  98.775
140   -.005  43.241    .008  21.078    .067    .289   6.501    .722    .066    .016  27.091    .000  99.074
141    .004  43.682    .006  21.467    .061    .271   6.770    .701    .062    .019  27.591    .000 100.633
142   -.001  44.168    .005  21.356    .081    .238   6.673    .646    .039    .013  27.448    .000 100.664
143   -.009  44.716    .003  21.192    .065    .268   6.559    .661    .053    .018  27.237    .000 100.764
144    .001  43.471    .012  21.088    .069    .301   6.644    .679    .042    .019  27.104    .000  99.429

AVER:    -.001  43.693    .007  21.224    .067    .271   6.587    .688    .058    .017  27.279    .000  99.890
SDEV:     .006    .661    .003    .155    .007    .022    .140    .031    .017    .002    .200    .000    .898
SERR:     .002    .270    .001    .063    .003    .009    .057    .013    .007    .001    .081    .000
%RSD:  -834.06    1.51   44.38     .73   10.91    8.26    2.12    4.53   29.36   14.98     .73  451.66
STDS:      336     285     285     336     336     395    1124     327     835     336       0       0

Un    5 Turquoise matrix3, Results Based on 6 Atoms of al

ELEM:       Na       P      Ca      Al       K      Fe      Cu       S      Ba      Si       H       O   SUM
137    .002   3.453    .001   6.000    .012    .035    .767    .057    .005    .004  15.996  26.039  52.373
140   -.002   3.497    .002   6.000    .013    .040    .786    .058    .004    .004  15.996  26.215  52.613
141    .001   3.469    .001   6.000    .012    .037    .803    .055    .003    .005  15.996  26.091  52.474
142    .000   3.525    .001   6.000    .016    .032    .796    .051    .002    .003  15.996  26.302  52.725
143   -.003   3.597    .001   6.000    .013    .037    .788    .053    .003    .005  15.996  26.595  53.083
144    .000   3.514    .002   6.000    .013    .041    .803    .054    .002    .005  15.996  26.269  52.701

AVER:     .000   3.509    .001   6.000    .013    .037    .791    .055    .003    .005  15.996  26.252  52.661
SDEV:     .002    .051    .001    .000    .001    .003    .014    .003    .001    .001    .000    .196    .247
SERR:     .001    .021    .000    .000    .001    .001    .006    .001    .000    .000    .000    .080
%RSD:  -823.52    1.45   44.83     .00   10.82    8.72    1.71    4.80   29.50   14.99     .00     .75

I have no idea if it is correct, but the total looks good!
The only stupid question is the one not asked!

#### Probeman

• Emeritus
• Posts: 1874
• Never sleeps...
##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #4 on: December 16, 2013, 01:17:34 pm »
In the previous turquoise sample, the Time Dependent Intensity (TDI) acquisition was very important as seen here for phosphorus:

See additional info on TDI here:

http://probesoftware.com/smf/index.php?topic=116.0
The only stupid question is the one not asked!

#### Probeman

• Emeritus
• Posts: 1874
• Never sleeps...
##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #5 on: December 16, 2013, 01:32:13 pm »
Here's an example of a carbonate calculated by measuring only the cations. Oxygen is calculated by stoichiometry and carbon is calculated by stoichiometry to the calculated (stoichiometric) oxygen:

St  135 Set   1 Calcite (analyzed)
TakeOff = 40.0  KiloVolt = 15.0  Beam Current = 30.0  Beam Size =    2
(Magnification (analytical) =   4000),        Beam Mode = Analog  Spot
(Magnification (default) =     3200, Magnification (imaging) =    100)
Image Shift (X,Y):                                          .00,   .00
Pre Acquire String :                                            PB OFF
Post Acquire String :                                            PB ON

Locality: unknown
XRF (UCB), ICP-MS (Washington Univ, D. Kremser)
Element    XRF-EDS    ICP-MS (ppm)
Sr            150       165
Mn            130       166
Fe            n.d.        4
Mg            n.d.       21
Number of Data Lines:   4             Number of 'Good' Data Lines:   4
First/Last Date-Time: 06/15/2008 10:14:18 AM to 06/15/2008 10:16:05 AM

Average Total Oxygen:       47.916     Average Total Weight%:  100.001
Average Calculated Oxygen:  47.918     Average Atomic Number:   12.575
Average Excess Oxygen:       -.002     Average Atomic Weight:   20.031
Average ZAF Iteration:        7.00     Average Quant Iterate:     2.00

Oxygen Calculated by Cation Stoichiometry and Included in the Matrix Correction
Element C is Calculated  .333 Atoms Relative To 1.0 Atom of Oxygen

St  135 Set   1 Calcite (analyzed), Results in Elemental Weight Percents

ELEM:       Ca      Mn      Fe      Mg       P       C       O
TYPE:     ANAL    ANAL    ANAL    ANAL    ANAL    STOI    CALC
BGDS:      LIN     LIN     LIN     LIN     LIN
TIME:    10.00   10.00   10.00   10.00   10.00
BEAM:    30.00   30.00   30.00   30.00   30.00

ELEM:       Ca      Mn      Fe      Mg       P       C       O   SUM
1  40.363   -.007   -.046    .000   -.011  11.959  47.943 100.202
2  40.049    .003    .038   -.002    .014  11.978  47.926 100.007
3  40.167   -.006    .016   -.021    .029  11.973  47.959 100.118
4  39.837    .046    .011   -.031   -.015  11.995  47.834  99.676

AVER:   40.104    .009    .005   -.013    .004  11.976  47.916 100.001
SDEV:     .220    .025    .036    .015    .021    .015    .056    .231
SERR:     .110    .012    .018    .007    .011    .007    .028
%RSD:      .55  271.48  732.18 -109.50  492.43     .12     .12

PUBL:   40.031    n.a.    n.a.    n.a.    n.a.  12.000  47.952  99.983
%VAR:      .18     ---     ---     ---     ---    -.20    -.08
DIFF:     .073     ---     ---     ---     ---   -.024   -.036
STDS:      138     140     145     139     285       0       0

STKF:    .3789   .3969   .4258   .1957   .1599   .0000   .0000
STCT:   3769.3  3961.2  4241.7  1936.5  1599.3      .0      .0

UNKF:    .3796   .0001   .0000  -.0001   .0000   .0000   .0000
UNCT:   3775.8      .7      .4     -.8      .4      .0      .0
UNBG:     37.5    30.7    38.3    15.3    21.4      .0      .0

ZCOR:   1.0566  1.2363  1.2120  1.6542  1.1569   .0000   .0000
KRAW:   1.0017   .0002   .0001  -.0004   .0002   .0000   .0000
PKBG:   101.97    1.03    1.01     .95    1.02     .00     .00

St  135 Set   1 Calcite (analyzed), Results Based on Sum of 2 Cations

ELEM:       Ca      Mn      Fe      Mg       P       C       O   SUM
1   1.006    .000   -.001    .000    .000    .995   2.994   4.994
2   1.000    .000    .001    .000    .000    .998   2.999   4.999
3   1.003    .000    .000   -.001    .001    .997   2.998   4.998
4    .998    .001    .000   -.001    .000   1.003   3.002   5.002

AVER:    1.002    .000    .000   -.001    .000    .998   2.998   4.998
SDEV:     .004    .000    .001    .001    .001    .003    .003    .003
SERR:     .002    .000    .000    .000    .000    .002    .002
%RSD:      .35  271.04  727.41 -109.60  493.78     .33     .10
The only stupid question is the one not asked!

#### Probeman

• Emeritus
• Posts: 1874
• Never sleeps...
##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #6 on: December 16, 2013, 01:43:05 pm »
You can also specify an element by stoichiometry to a measured element (1 C to 1 Ca), oxygen by stoichiometric calculation and an element by stoichiometry to calculated oxygen (.333 C to 1 O) as seen here:

St  138 Set   1 Calcite (Harvard #97189)
TakeOff = 40.0  KiloVolt = 15.0  Beam Current = 30.0  Beam Size =    2
(Magnification (analytical) =   4000),        Beam Mode = Analog  Spot
(Magnification (default) =     3200, Magnification (imaging) =    100)
Image Shift (X,Y):                                          .00,   .00
Pre Acquire String :                                            PB OFF
Post Acquire String :                                            PB ON

Specimen from Harvard Mineralogical Museum (Carl Francis)
Locality: Oberdorf, Austria
EPMA (UCB): MnO=0.01, FeO=0.00, MgO=0.00
See Garrels, et al., 1980 AJS 258, 402-418
Number of Data Lines:   4             Number of 'Good' Data Lines:   4
First/Last Date-Time: 06/15/2008 10:16:54 AM to 06/15/2008 10:18:38 AM

Average Total Oxygen:       47.949     Average Total Weight%:   99.995
Average Calculated Oxygen:  47.951     Average Atomic Number:   12.568
Average Excess Oxygen:       -.002     Average Atomic Weight:   20.021
Average ZAF Iteration:        2.00     Average Quant Iterate:     2.00

Oxygen Calculated by Cation Stoichiometry and Included in the Matrix Correction
Element C is Calculated  .333 Atoms Relative To 1.0 Atom of Oxygen
Element C is Calculated  1 Atoms Relative To 1.0 Atom of Ca

St  138 Set   1 Calcite (Harvard #97189), Results in Elemental Weight Percents

ELEM:       Ca      Mn      Fe      Mg       P       C       O
TYPE:     ANAL    ANAL    ANAL    ANAL    ANAL    STOI    CALC
BGDS:      LIN     LIN     LIN     LIN     LIN
TIME:    10.00   10.00   10.00   10.00   10.00
BEAM:    30.00   30.00   30.00   30.00   30.00

ELEM:       Ca      Mn      Fe      Mg       P       C       O   SUM
5  39.853    .062   -.005   -.019    .010  11.943  47.742  99.584
6  40.366    .010   -.005   -.035    .044  12.097  48.375 100.852
7  39.844   -.034    .034   -.035   -.026  11.940  47.658  99.380
8  40.085    .043   -.012    .018   -.003  12.013  48.021 100.165

AVER:   40.037    .020    .003   -.018    .006  11.998  47.949  99.995
SDEV:     .246    .042    .021    .025    .029    .074    .324    .661
SERR:     .123    .021    .010    .012    .015    .037    .162
%RSD:      .61  209.49  721.04 -138.86  473.91     .61     .68

PUBL:   40.038    .008    .000    .000    n.a.  12.000  47.954 100.000
%VAR:    (.00)  150.10     .00     .00     ---    -.02    -.01
DIFF:    (.00)    .012    .000    .000     ---   -.002   -.005
STDS:      138     140     145     139     285       0       0

STKF:    .3789   .3969   .4258   .1957   .1599   .0000   .0000
STCT:   3769.3  3961.2  4241.7  1936.5  1599.3      .0      .0

UNKF:    .3789   .0002   .0000  -.0001   .0001   .0000   .0000
UNCT:   3769.3     1.6      .2    -1.1      .5      .0      .0
UNBG:     40.0    31.0    38.8    16.1    22.2      .0      .0

ZCOR:   1.0566  1.2363  1.2120  1.6542  1.1570   .0000   .0000
KRAW:   1.0000   .0004   .0001  -.0005   .0003   .0000   .0000
PKBG:    95.31    1.06    1.01     .94    1.03     .00     .00

St  138 Set   1 Calcite (Harvard #97189), Results Based on 1 Atoms of c

ELEM:       Ca      Mn      Fe      Mg       P       C       O   SUM
5   1.000    .001    .000   -.001    .000   1.000   3.001   5.001
6   1.000    .000    .000   -.001    .001   1.000   3.002   5.002
7   1.000   -.001    .001   -.001   -.001   1.000   2.996   4.994
8   1.000    .001    .000    .001    .000   1.000   3.001   5.002

AVER:    1.000    .000    .000   -.001    .000   1.000   3.000   5.000
SDEV:     .000    .001    .000    .001    .001    .000    .003    .004
SERR:     .000    .000    .000    .001    .000    .000    .001
%RSD:      .00  210.32  711.86 -138.67  480.74     .00     .09

So let's calculate oxygen by stoichiometry and do carbon 0.333 C to calculated O. So on a complex carbonate it looks like this:

St  143 Set   1 Kutnahorite (Harvard #85670)
TakeOff = 40.0  KiloVolt = 15.0  Beam Current = 30.0  Beam Size =    2
(Magnification (analytical) =   4000),        Beam Mode = Analog  Spot
(Magnification (default) =     3200, Magnification (imaging) =    100)
Image Shift (X,Y):                                          .00,   .00
Pre Acquire String :                                            PB OFF
Post Acquire String :                                            PB ON

Specimen from Harvard Mineralogical Museum (Carl Francis)
Locality: Franklin, NJ
See Garrels, et al., 1980 AJS 258, 402-418
Also J. V. Smith, Am. Jour. Sci. 1960
Number of Data Lines:   4             Number of 'Good' Data Lines:   4
First/Last Date-Time: 06/15/2008 10:27:04 AM to 06/15/2008 10:28:50 AM

Average Total Oxygen:       45.509     Average Total Weight%:  100.231
Average Calculated Oxygen:  45.512     Average Atomic Number:   13.971
Average Excess Oxygen:       -.003     Average Atomic Weight:   21.131
Average ZAF Iteration:        7.00     Average Quant Iterate:     2.00

Oxygen Calculated by Cation Stoichiometry and Included in the Matrix Correction
Element C is Calculated  .333 Atoms Relative To 1.0 Atom of Oxygen

St  143 Set   1 Kutnahorite (Harvard #85670), Results in Elemental Weight Percents

ELEM:       Ca      Mn      Fe      Mg       P       C       O
TYPE:     ANAL    ANAL    ANAL    ANAL    ANAL    STOI    CALC
BGDS:      LIN     LIN     LIN     LIN     LIN
TIME:    10.00   10.00   10.00   10.00   10.00
BEAM:    30.00   30.00   30.00   30.00   30.00

ELEM:       Ca      Mn      Fe      Mg       P       C       O   SUM
21  19.734  22.026    .382   1.385    .021  11.333  45.532 100.412
22  19.850  21.699    .401   1.377    .016  11.354  45.532 100.229
23  19.615  21.856    .321   1.278   -.008  11.366  45.396  99.824
24  19.767  21.962    .363   1.423    .032  11.338  45.574 100.460

AVER:   19.741  21.886    .367   1.365    .015  11.348  45.509 100.231
SDEV:     .097    .143    .034    .062    .017    .015    .077    .289
SERR:     .049    .071    .017    .031    .009    .007    .039
%RSD:      .49     .65    9.30    4.53  112.08     .13     .17

PUBL:   19.612  21.925    .389   1.333    .000  11.408  45.594 100.261
%VAR:      .66    -.18   -5.70    2.43     .00    -.53    -.19
DIFF:     .129   -.039   -.022    .032    .000   -.060   -.085
STDS:      138     140     145     139     285       0       0

STKF:    .3789   .3969   .4258   .1957   .1599   .0000   .0000
STCT:   3769.3  3961.2  4241.7  1936.5  1599.3      .0      .0

UNKF:    .1930   .1843   .0031   .0077   .0001   .0000   .0000
UNCT:   1919.6  1839.4    31.3    75.8     1.3      .0      .0
UNBG:     31.1    43.3    42.8    14.2    22.8      .0      .0

ZCOR:   1.0230  1.1875  1.1669  1.7823  1.1895   .0000   .0000
KRAW:    .5093   .4644   .0074   .0392   .0008   .0000   .0000
PKBG:    62.65   43.58    1.74    6.38    1.06     .00     .00

St  143 Set   1 Kutnahorite (Harvard #85670), Results in Oxide Weight Percents

ELEM:      CaO     MnO     FeO     MgO    P2O5     CO2       O   SUM
21  27.611  28.440    .492   2.297    .048  41.527   -.003 100.412
22  27.774  28.019    .516   2.283    .038  41.603   -.003 100.229
23  27.446  28.221    .413   2.119   -.019  41.647   -.003  99.824
24  27.658  28.359    .467   2.359    .073  41.546   -.003 100.460

AVER:   27.622  28.260    .472   2.264    .035  41.581   -.003 100.231
SDEV:     .136    .184    .044    .103    .039    .055    .000    .289
SERR:     .068    .092    .022    .051    .020    .027    .000
%RSD:      .49     .65    9.30    4.53  112.08     .13    -.06

PUBL:   27.441  28.310    .500   2.211    .000  41.801   -.003 100.261
%VAR:      .66    -.18   -5.70    2.43     .00    -.53    -.03
DIFF:     .181   -.051   -.029    .054    .000   -.221    .000
STDS:      138     140     145     139     285       0       0

St  143 Set   1 Kutnahorite (Harvard #85670), Results Based on 1 Atoms of c

ELEM:       Ca      Mn      Fe      Mg       P       C       O   SUM
21    .522    .425    .007    .060    .001   1.000   3.016   5.031
22    .524    .418    .008    .060    .001   1.000   3.010   5.020
23    .517    .420    .006    .056    .000   1.000   2.998   4.997
24    .522    .423    .007    .062    .001   1.000   3.017   5.033

AVER:     .521    .422    .007    .059    .001   1.000   3.011   5.020
SDEV:     .003    .003    .001    .003    .001    .000    .009    .016
SERR:     .001    .002    .000    .001    .000    .000    .004
%RSD:      .56     .75    9.36    4.64  112.00     .00     .29

The only stupid question is the one not asked!

#### BenH

• Post Doc
• Posts: 12
##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #7 on: February 04, 2015, 01:59:53 pm »
Is there any way that I can calculate more than one element as an atomic ratio to another element?
I know the composition of my base glass quite well and I know that the molar ratios stay the same.  Since this stuff is loaded with alkali I would like not to have to do more than one element per spectrometer.  Even “fixing” and element as a constant would due because the elements in question are in low abundances and are light elements.

#### John Donovan

• Emeritus
• Posts: 2424
• Other duties as assigned...
##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #8 on: February 04, 2015, 02:26:52 pm »
Is there any way that I can calculate more than one element as an atomic ratio to another element?
I know the composition of my base glass quite well and I know that the molar ratios stay the same.  Since this stuff is loaded with alkali I would like not to have to do more than one element per spectrometer.  Even “fixing” and element as a constant would due because the elements in question are in low abundances and are light elements.

Not specifically.  But once the atomic ratios are calculated every element has a stoichiometry to every other element.

Also, the previous post shows how to do oxygen by stoichiometry plus another element relative to another.

I'm probably missing what you are really asking. Can you provide an example?
john
John J. Donovan, Pres.
(541) 343-3400

"Not Absolutely Certain, Yet Reliable"

#### Gseward

• Global Moderator
• Professor
• Posts: 128
##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #9 on: February 04, 2015, 04:44:46 pm »
John,

Ideally I would like to be able to  'add a compound by difference'. In this case Li2B4O7
Initially I thought I could do this for simple compounds by doing this:

However, in this situation it seems the element is added by difference, but the element by stoichiometry to it, is not added. It seems this could be possible if you checked for 'elements stoichiometric to element by difference' before adding both (or perhaps more?) to the matrix???
« Last Edit: June 17, 2015, 04:41:15 pm by John Donovan »

#### John Donovan

• Emeritus
• Posts: 2424
• Other duties as assigned...
##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #10 on: February 04, 2015, 05:09:09 pm »
Ideally I would like to be able to  'add a compound by difference'. In this case Li2B4O7
Initially I thought I could do this for simple compounds by doing this:

[snip]

However, in this situation it seems the element is added by difference, but the element by stoichiometry to it, is not added. It seems this could be possible if you checked for 'elements stoichiometric to element by difference' before adding both (or perhaps more?) to the matrix???

It is a good suggestion, but difficult to implement in code and keep all the other existing specification method working.  It gets complicated... A lot of it has to do with the order that things are calculated (as you correctly point out!).

But I did get something to kinda of work along the lines you need, here using this specification:

Here is the output:

ELEM:       Ti      Fe      Al      Mn      Mg      Si      Ca       O      Li       B
TYPE:     ANAL    ANAL    ANAL    ANAL    ANAL    SPEC    SPEC    CALC    STOI    RELA
BGDS:      EXP     LIN     AVG     LIN     LIN
TIME:  1200.00 1200.00 1200.00 1200.00 1200.00
BEAM:   100.09  100.09  100.09  100.09  100.09

ELEM:       Ti      Fe      Al      Mn      Mg      Si      Ca       O      Li       B   SUM
142  .00152  .01969  .00020  .01182  .03467  .00000  .00000 64.8992 8.03761 25.0453 98.0500
143  .00117  .02084  .00070  .01177  .03541  .00000  .00000 64.8992 8.03748 25.0449 98.0515
144  .00151  .02067  .00028  .01170  .03578  .00000  .00000 64.8993 8.03748 25.0449 98.0515

AVER:   .00140  .02040  .00039  .01176  .03529    .000    .000  64.899   8.038  25.045 98.0510
SDEV:   .00020  .00062  .00027  .00006  .00056    .000    .000    .000    .000    .000  .00088
SERR:   .00012  .00036  .00015  .00004  .00032  .00000  .00000  .00001  .00004  .00013
%RSD:  14.4836 3.03898 68.0015  .53620 1.59054  .00000  .00000  .00003  .00088  .00087
STDS:       22     395     336     140      12       0       0       0       0       0

STKF:    .5616   .6862   .1159   .4052   .4215   .0000   .0000   .0000   .0000   .0000
STCT:  1894.84 1019.49  330.27  164.35  978.80     .00     .00     .00     .00     .00

UNKF:    .0000   .0002   .0000   .0001   .0002   .0000   .0000   .0000   .0000   .0000
UNCT:      .04     .26     .01     .04     .46     .00     .00     .00     .00     .00
UNBG:     3.08    1.43    1.28     .31     .70     .00     .00     .00     .00     .00

ZCOR:   1.1405  1.1652  1.4834  1.1816  1.8006   .0000   .0000   .0000   .0000   .0000
KRAW:   .00002  .00026  .00002  .00025  .00046  .00000  .00000  .00000  .00000  .00000
PKBG:  1.01348 1.18203 1.00592 1.12886 1.64704  .00000  .00000  .00000  .00000  .00000
BLNK#:    ----    ----    ----    ----    ----    ----    ----    ----    ----    ----
BLNKL:    ----    ----    ----    ----    ----    ----    ----    ----    ----    ----
BLNKV:    ----    ----    ----    ----    ----    ----    ----    ----    ----    ----

Un    3, Results in Atomic Percents

ELEM:       Ti      Fe      Al      Mn      Mg      Si      Ca       O      Li       B   SUM
142  .00042  .00468  .00010  .00286  .01894  .00000  .00000 53.8443 15.3762 30.7525 100.000
143  .00032  .00495  .00035  .00284  .01934  .00000  .00000 53.8443 15.3760 30.7520 100.000
144  .00042  .00491  .00014  .00283  .01954  .00000  .00000 53.8442 15.3760 30.7520 100.000

AVER:   .00039  .00485  .00019  .00284  .01927    .000    .000  53.844  15.376  30.752 100.000
SDEV:   .00006  .00015  .00013  .00002  .00031    .000    .000    .000    .000    .000  .00000
SERR:   .00003  .00009  .00008  .00001  .00018  .00000  .00000  .00002  .00009  .00017
%RSD:  14.4836 3.03890 68.0015  .53628 1.59046  .00000  .00000  .00006  .00096  .00096

Yes, the unnormalized total is a little low, but probably good enough for the matrix correction!

Maybe this would work for Ben's situation also?

Of course one can also just simply specify the concentrations explicitly from the Specified Concentrations button in Analyze!
« Last Edit: February 04, 2015, 05:26:11 pm by John Donovan »
John J. Donovan, Pres.
(541) 343-3400

"Not Absolutely Certain, Yet Reliable"

#### Gseward

• Global Moderator
• Professor
• Posts: 128
##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #11 on: February 04, 2015, 05:50:11 pm »
John,

Thanks for the reply. I think in a situation where the measured elements are in low concentration, your suggestion would work. But as you say, in the situation where the measured elements are only trace, one can simply add the matrix from the Specified Concentrations menu.
When the measured elements are a more significant contribution (and thus they have stoich O also), adding the Li relative to the calculated oxygen might become problematic. For my situation I can add approximately the correct amount of Li2B4O7 as a specified concentration, and probably get close enough, but obviously the specified concentration is not involved in any iterations.

Cheers,

Gareth

#### BenH

• Post Doc
• Posts: 12
##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #12 on: February 05, 2015, 08:48:40 am »
I have glasses that we are ion exchanging.  That means that the glass is immersed in a molten salt bath and alkalis exchange at the surface one for one.  The base glass composition is well known.  I don’t really need to analyze the 3 minor elements in the sample.  So I do 2 light minor elements by mole ratio to a measured element.  I do Li by difference.

I need a way to do more than one element by mole ratio to a measured major element.  Is there a way to do that?  If not, is that something that can be modified without burning the building down?

#### John Donovan

• Emeritus
• Posts: 2424
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##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #13 on: February 05, 2015, 09:54:23 am »
I have glasses that we are ion exchanging.  That means that the glass is immersed in a molten salt bath and alkalis exchange at the surface one for one.  The base glass composition is well known.  I don’t really need to analyze the 3 minor elements in the sample.  So I do 2 light minor elements by mole ratio to a measured element.  I do Li by difference.

I need a way to do more than one element by mole ratio to a measured major element.  Is there a way to do that?  If not, is that something that can be modified without burning the building down?

I think I should add a formula by difference option to the Calculation Options which would take care of this situation nicely. I'll do that ASAP and let you know when it is ready to download...

In the meantime you can specify fixed concentrations as a formula in the Specified Concentrations dialog as seen here:

The totals may not be perfect if your measured minor elements are significant, but it might be good enough for the matrix correction of the minor elements.
John J. Donovan, Pres.
(541) 343-3400

"Not Absolutely Certain, Yet Reliable"

#### John Donovan

• Emeritus
• Posts: 2424
• Other duties as assigned...
##### Re: Specifying Unanalyzed Elements For a Proper Matrix Correction
« Reply #14 on: June 17, 2015, 04:47:42 pm »
Ok, the requested formula by difference feature has been added to both the ZAF, Phi-rho-z and alpha factor methods (not yet for the multi-standard calibration curve method), as described here:

http://probesoftware.com/smf/index.php?topic=42.msg2568#msg2568
John J. Donovan, Pres.
(541) 343-3400

"Not Absolutely Certain, Yet Reliable"