Quantitative Apatite Analysis

[BenjaminWade]

Hi Jeremy
I had a good look and made a list, looked at the prices and cut some off the list...so I am left with MgF2, TiO2, SiO2, and YVO4. That would be great if you could add them to the list.

Cheers

[AndrewLocock]

Hello,
An alternative source of high-purity MgF2 is Sigma-Aldrich, catalog number 378836: "Magnesium fluoride, random crystals, optical grade, ≥99.99% trace metals basis, Synonym: Sellaite". A quantity of 5 grams is available for $128 (Cdn), before an academic discount, if any.
Best regards,
Andrew

[EricKelly]

I am revisiting this topic to post our new protocol for apatite, which might be useful to others.  The most notable part of this is that our biggest improvement came from obtaining new standards.

After getting poor results from Utah Topaz, Fluorite, or Durango Apatite as primary standards for F, we obtained MgF2 (Sigma-Aldrich, 378836 - Thanks for the tip Andrew) and saw big improvements.  We also obtained several of the Schettler et al. (2011, American Mineralogist v96 p138-152) synthetic apatite crystals for Ca, P, and Cl.  Our APS-26 grain works well as a primary standard.  We tried several others for use as secondary standards and found that APS-27 worked well.  Durango apatite now serves as a secondary standard in our lab (This seems to be another example of Durango’s variability, given that it works as a primary standard in some labs and not others).

Our goal was to develop a fast protocol to handle a large number of grains.  For those grains that require better analyses, we will return to them with longer counting times and fewer trace elements.  Starting with Anette’s protocol and other comments from the forum, we now use the following on our JEOL 8200:

Analytical conditions:
15 kV
10 nA
10 micron spot diameter

Crystal assignments:
LDE (with expanded slit): F
TAP: Na, Si
PETH/J: Ca, P, Cl, Sr, Ce, Nd
LIFH: Fe, Mn

Peak/background counting times:
F: 50/25
Cl, Na, and Si: 40/20
All others: 20/10 (or 30/15 for better analyses)

Frequency of background measurements:
F, Cl, Ca, P: Every analysis
All others: First analysis of a grain only (Nth backgrounds)

Other options:
We use an exponential fit for F backgrounds (and Ce)
We include TDI measurements, but for our samples typically Ca and F are the only elements that need a TDI fit, and Ca rarely needs it.
We use PFE’s halogen correction (or apply our own correction).
We recalibrate every 12 hours or so using different spot locations on standards that contain migrating elements, but so far have not seen significant drift.

Thanks again for everyone’s help.

[Brian Joy]

I would urge extreme caution in using MgF2 as a standard for analysis of F in apatite.  In this case the F Ka absorption correction is astronomically large, and hence the accuracy of the correction is not likely to be good.  For instance, using PAP in conjunction with MAC values suggested by Pouchou and Pichoir (in Electron Probe Quantitation) and using 15 kV potential and 40 deg. takeoff angle, f(chi) for F Ka in MgF2 is 0.6090, while in Ca5(PO4)3F it is 0.1355.  This produces an absorption correction factor of 4.494, i.e. a correction of ~350%.  Any small error in MACs or in the phi(rho*z) model could affect calculated wt% F significantly.  Not only is F Ka strongly absorbed by oxygen, but it is roughly equally strongly absorbed by Ca, as it is energetic enough to ionize Ca L1,2,3.  For instance, comparison of F Ka f(chi) in MgF2 and CaF2 gives 0.6090 versus 0.2180.  Other problems notwithstanding (TDI, for instance), if there ever were a case in which a “matrix match” were needed between standard and unknown, the analysis of F in apatite is it.

Also, when analyzing for F using LDE1, are you taking into account the overlap from P Ka(3)?  If you are using pulse amplitude discrimination, have you verified that you have completely eliminated the contribution from P Ka?  For instance, have you done a wavelength scan for F Ka in differential mode on a nominally F-free material such as Ca2P2O7 (calcium pyrophosphate), which has roughly similar wt% CaO and P2O5 as apatite?

[Probeman]

Other options:
We use an exponential fit for F backgrounds (and Ce)

We include TDI measurements, but for our samples typically Ca and F are the only elements that need a TDI fit, and Ca rarely needs it.

We use PFE’s halogen correction (or apply our own correction).

Hi Eric,
Very nice.  A couple of questions...

For F ka did you use a 40 or 60 angstrom LDE?

Can you provide some example output from PFE?  I'm especially interested in the difference between the results with and without the halogen - oxygen equivalent correction.

Also maybe could you post a couple graphs of the TDI effects?  I've seen some strange behavior there and wondered how your curves look.

[Probeman]

I would urge extreme caution in using MgF2 as a standard for analysis of F in apatite.  In this case the F Ka absorption correction is astronomically large, and hence the accuracy of the correction is not likely to be good.  For instance, using PAP in conjunction with MAC values suggested by Pouchou and Pichoir (in Electron Probe Quantitation) and using 15 kV potential and 40 deg. takeoff angle, f(chi) for F Ka in MgF2 is 0.6090, while in Ca5(PO4)3F it is 0.1355.  This produces an absorption correction factor of 4.494, i.e. a correction of ~350%.  Any small error in MACs or in the phi(rho*z) model could affect calculated wt% F significantly.  Not only is F Ka strongly absorbed by oxygen, but it is roughly equally strongly absorbed by Ca, as it is energetic enough to ionize Ca L1,2,3.  For instance, comparison of F Ka f(chi) in MgF2 and CaF2 gives 0.6090 versus 0.2180.  Other problems notwithstanding (TDI, for instance), if there ever were a case in which a “matrix match” were needed between standard and unknown, the analysis of F in apatite is it.

Also, when analyzing for F using LDE1, are you taking into account the overlap from P Ka(3)?  If you are using pulse amplitude discrimination, have you verified that you have completely eliminated the contribution from P Ka?  For instance, have you done a wavelength scan for F Ka in differential mode on a nominally F-free material such as Ca2P2O7 (calcium pyrophosphate), which has roughly similar wt% CaO and P2O5 as apatite?

Hi Brian,
I think you make some good points.

On the standard for fluorine I suspect that a robust standard may be more import than the matrix match.  Here are some comparisons between the Heinrich, Henke and FFAST MACs for these matrices:

MAC value for F ka in O =   12439.63  (LINEMU   Henke (LBL, 1985) < 10KeV / CITZMU > 10KeV)
MAC value for F ka in O =   12390.00  (CITZMU   Heinrich (1966) and Henke and Ebisu (1974))
MAC value for F ka in O =   11927.75  (MAC30    Heinrich (Fit to Goldstein tables, 1987))
MAC value for F ka in O =   11863.62  (FFAST    Chantler (NIST v 2.1, 2005))

MAC value for F ka in Ca =   12415.20  (LINEMU   Henke (LBL, 1985) < 10KeV / CITZMU > 10KeV)
MAC value for F ka in Ca =   12370.00  (CITZMU   Heinrich (1966) and Henke and Ebisu (1974))
MAC value for F ka in Ca =   12623.93  (MAC30    Heinrich (Fit to Goldstein tables, 1987))
MAC value for F ka in Ca =   12132.31  (FFAST    Chantler (NIST v 2.1, 2005))

MAC value for F ka in P =    5550.00  (LINEMU   Henke (LBL, 1985) < 10KeV / CITZMU > 10KeV)
MAC value for F ka in P =    5526.00  (CITZMU   Heinrich (1966) and Henke and Ebisu (1974))
MAC value for F ka in P =    5219.60  (MAC30    Heinrich (Fit to Goldstein tables, 1987))
MAC value for F ka in P =    4905.57  (FFAST    Chantler (NIST v 2.1, 2005))


The MAC for F ka by P is fairly small and the others are larger but in relative agreement, but I do think having a matrix match is ideal as you suggest.

I wonder if we should talk to Marc Schrier about the possibility of synthesizing an end member fluor-apatite?  Wouldn't that be nice to have for everyone?

I already have a synthetic chlor-apatite (just a few grains left, but hydrothermally grown from the University of Nice, see Argiolas and Baumer, Can. Min., v. 16, pp 285-290, 1978), which is wonderful, though a little beam sensitive. Fortunately the Cl intensity doesn't seem to change much over time with mild beam conditions.  I should also mention to Marc him synthesizing this in 100 - 200 gram quantities as well...

By the way, I received about 200 grams of RbTiOPO4 and after we analyze it for traces I will be sending it to Marc Schrier for distribution, so I'll let you know when that is ready.

Back to fluor-apatite though- the question isn't so much the size of the matrix correction relative to the standard, though it is worth considering, but the relative accuracy error on that correction is important I agree. Here is a comparison of two different matrix corrections on a fluor-apatite material (all using the same MACs) done by a student at the USGS so please ignore the accuracy!  I also cut out most of the elements because she analyzed 36 elements in this standard!

First the JTA matrix correction (the default in my software):

ELEM:        W      Ta      Fe      Ti      Nb      Mn      Na       F   SUM 
   100    .000    .000    .079    .000    .011    .037    .157   4.342 101.390
   101    .000    .000    .000    .306    .000    .007    .130   3.655 100.569
   102    .000    .000    .000    .000    .020    .038    .139   4.484 101.617

AVER:     .000    .000    .026    .102    .011    .028    .142   4.160 101.192
SDEV:     .000    .000    .045    .176    .010    .017    .014    .444    .551
SERR:     .000    .000    .026    .102    .006    .010    .008    .256
%RSD:      .16     .19  173.20  173.21   96.92   63.20    9.61   10.66

PUBL:     n.a.    n.a.    n.a.    n.a.    n.a.    n.a.    .178   3.700  99.662
%VAR:      ---     ---     ---     ---     ---     ---  -20.44   12.44
DIFF:      ---     ---     ---     ---     ---     ---   -.036    .460
STDS:      468     467    7852    7840     442    7845    7815    8811

STKF:   1.0000  1.0000   .4985   .5548  1.0000   .1418   .0505   .1537
STCT:   602.94  622.84   44.65   43.13  135.92   13.23   52.31   16.58

UNKF:    .0000   .0000   .0002   .0008   .0001   .0002   .0007   .0083
UNCT:    -1.53    -.86     .01     .05     .00     .02     .68     .89
UNBG:     4.20    3.11     .29     .03     .27     .29     .80     .15

ZCOR:   1.1917  1.2114  1.1812  1.2234  1.2559  1.2066  2.1646  5.0168
KRAW:   -.0025  -.0014   .0002   .0011   .0000   .0016   .0129   .0540
PKBG:      .64     .72    1.04     .52     .99    1.08    1.85    7.21
INT%:     5.62     .30    ----    ----    ----    ----    ----  -18.21


And here is the original PAP (XPP) correction:

ELEM:        W      Ta      Fe      Ti      Nb      Mn      Na       F   SUM 
   100    .000    .000    .079    .000    .012    .037    .153   4.386 101.453
   101    .000    .000    .000    .307    .000    .007    .127   3.715 100.627
   102    .000    .000    .000    .000    .022    .038    .136   4.549 101.685

AVER:     .000    .000    .026    .102    .012    .028    .139   4.217 101.255
SDEV:     .000    .000    .046    .177    .011    .017    .013    .442    .556
SERR:     .000    .000    .026    .102    .006    .010    .008    .255
%RSD:      .13     .15  173.20  173.21   96.94   63.20    9.43   10.48

PUBL:     n.a.    n.a.    n.a.    n.a.    n.a.    n.a.    .178   3.700  99.662
%VAR:      ---     ---     ---     ---     ---     ---  -22.07   13.96
DIFF:      ---     ---     ---     ---     ---     ---   -.039    .517
STDS:      468     467    7852    7840     442    7845    7815    8811

STKF:   1.0000  1.0000   .4892   .5435  1.0000   .1383   .0485   .1498
STCT:   602.94  622.84   44.65   43.13  135.92   13.23   52.31   16.58

UNKF:    .0000   .0000   .0002   .0008   .0001   .0002   .0006   .0081
UNCT:    -1.53    -.86     .01     .05     .00     .02     .68     .90
UNBG:     4.20    3.11     .29     .03     .27     .29     .80     .15

ZCOR:   1.3693  1.3918  1.2122  1.2560  1.3782  1.2383  2.2085  5.2191
KRAW:   -.0025  -.0014   .0002   .0011   .0000   .0016   .0129   .0540
PKBG:      .64     .72    1.04     .52     .99    1.08    1.85    7.21
INT%:     5.62     .30    ----    ----    ----    ----    ----  -18.19


The matrix correction for F Ka goes from 5.0168 to 5.2191 so about 4% which is less than the relative standard deviation. 

Also, the interference from P Ka III is important and I observe that on my Sx100, and it should be a slightly larger overlap on a JEOL instrument. For that of course we'd like to have a material with known P and no F, for instance the chlor-apatite standard I mentioned above. By the way, the above analyses are with the P III interference on F Ka corrected (see the line labeled INT% which is the interference correction percent which is ~18% so that is quite important as you mentioned.

Lots more to discuss here...

[Marc Schrier]

John, I found the paper at http://rruff.info/uploads/CM16_285.pdf  Unfortunately I took Spanish in school, so I'm not doing really well with this French paper.  Copying and pasting sections into a translator is giving me a sense for the paper, but not to enough detail yet.  I do have a Leco Tem-Pres Reactor, so the 1-3000 bar and 200-850°C (I cannot go beyond 750°C) are possibilities.  But... the reactor volume is just 28.2 cc, and if I use gold tubes like they did, it's dramatically less, so I  would not get very much material.  I did a search to see if I could find any other papers (hopefully one in English too), and I found several where chlorapatite was prepared from a molten flux, CaCl2.  That's much more amenable to bulk syntheses!  Two papers I saw were: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3638812/ and http://journal.chemistrycentral.com/content/7/1/56  Are you guys familiar with chlorapatite prepared in this fashion?     -Marc

[John Donovan]

John, I found the paper at http://rruff.info/uploads/CM16_285.pdf  Unfortunately I took Spanish in school, so I'm not doing really well with this French paper.

I'm pretty sure I found the paper in The Canadian Mineralogist...  in English.

[EricKelly]

I would urge extreme caution in using MgF2 as a standard for analysis of F in apatite.  In this case the F Ka absorption correction is astronomically large, and hence the accuracy of the correction is not likely to be good.  For instance, using PAP in conjunction with MAC values suggested by Pouchou and Pichoir (in Electron Probe Quantitation) and using 15 kV potential and 40 deg. takeoff angle, f(chi) for F Ka in MgF2 is 0.6090, while in Ca5(PO4)3F it is 0.1355.  This produces an absorption correction factor of 4.494, i.e. a correction of ~350%.  Any small error in MACs or in the phi(rho*z) model could affect calculated wt% F significantly.  Not only is F Ka strongly absorbed by oxygen, but it is roughly equally strongly absorbed by Ca, as it is energetic enough to ionize Ca L1,2,3.  For instance, comparison of F Ka f(chi) in MgF2 and CaF2 gives 0.6090 versus 0.2180.  Other problems notwithstanding (TDI, for instance), if there ever were a case in which a “matrix match” were needed between standard and unknown, the analysis of F in apatite is it.

Also, when analyzing for F using LDE1, are you taking into account the overlap from P Ka(3)?  If you are using pulse amplitude discrimination, have you verified that you have completely eliminated the contribution from P Ka?  For instance, have you done a wavelength scan for F Ka in differential mode on a nominally F-free material such as Ca2P2O7 (calcium pyrophosphate), which has roughly similar wt% CaO and P2O5 as apatite?

Hi Brian,

How appropriate that you responded – you were my TA at Davis!

I also prefer to matrix-match the standard to the unknown, but all of the other standards I’ve tried gave impossible F compositions (>4 wt%).  Of course there may be something else wrong and the MgF2 standard fortuitously brings the F counts into alignment, but I haven’t found anything else to blame.  I am happy to hear more suggestions though.

Thanks for bringing up the P III peak issue.  I think I’ve excluded it in my runs so far.  Here are a couple of screenshots from a wavescan done on a nearly pure chlorapatite.  The first image shows the location of the F peak, and the second shows the P peak.

[EricKelly]

Other options:
We use an exponential fit for F backgrounds (and Ce)

We include TDI measurements, but for our samples typically Ca and F are the only elements that need a TDI fit, and Ca rarely needs it.

We use PFE’s halogen correction (or apply our own correction).

Hi Eric,
Very nice.  A couple of questions...

For F ka did you use a 40 or 60 angstrom LDE?

Can you provide some example output from PFE?  I'm especially interested in the difference between the results with and without the halogen - oxygen equivalent correction.

Also maybe could you post a couple graphs of the TDI effects?  I've seen some strange behavior there and wondered how your curves look.

I don’t remember off-hand which LDE crystal we have.  I think the spacing is 60 but I’ll have to check when I’m back on campus tomorrow.

Here are results from one of the synthetic standards (Schettler et al).  The halogen correction gives slightly better results.  I attached a longer print out in case anyone wants to see more.

Halogen corrected
TDI log-linear fit to F

St  209 Set   1 Apatite APS-27, Results in Oxide Weight Percents

ELEM:     P2O5       F      Cl     MnO     FeO     CaO       O   SUM 
    30  41.505   2.512   2.135    .043    .008  54.989  -3.039  98.151
    31  41.652   2.442   2.192   -.076    .036  54.656  -3.023  97.879
    32  42.261   2.350   2.158    .017   -.004  54.783  -2.976  98.588
    33  42.090   2.350   2.158   -.008   -.009  54.980  -2.976  98.585
    34  41.784   2.509   2.213    .046    .040  54.826  -3.056  98.362
    35  42.034   2.321   2.164   -.039    .019  54.820  -2.965  98.353
    36  42.011   2.518   2.129    .034    .028  55.012  -3.041  98.691
    37  41.605   2.601   2.173    .014   -.010  55.114  -3.086  98.411
    38  42.069   2.413   2.168   -.021    .034  55.166  -3.005  98.824

AVER:   41.890   2.446   2.166    .001    .016  54.927  -3.019  98.427
SDEV:     .260    .095    .026    .041    .020    .166    .041    .288
SERR:     .087    .032    .009    .014    .007    .055    .014
%RSD:      .62    3.90    1.20 4609.42  127.17     .30   -1.35

PUBL:   41.863   2.472   2.290    n.a.    n.a.  54.874  -1.500 100.000
%VAR:      .06   -1.06   -5.42     ---     ---     .10  101.26
DIFF:     .027   -.026   -.124     ---     ---    .053  -1.519
STDS:      211     206     211      42      39     211       0




Without halogen correction

St  209 Set   1 Apatite APS-27, Results in Oxide Weight Percents

ELEM:     P2O5       F      Cl     MnO     FeO     CaO       O   SUM 
    30  41.556   2.521   2.135    .043    .008  55.016  -1.500  99.778
    31  41.703   2.451   2.193   -.076    .036  54.682  -1.500  99.489
    32  42.310   2.359   2.158    .017   -.004  54.808  -1.500 100.148
    33  42.139   2.358   2.159   -.008   -.009  55.005  -1.500 100.145
    34  41.836   2.518   2.213    .046    .040  54.853  -1.500 100.006
    35  42.082   2.329   2.164   -.039    .019  54.845  -1.500  99.901
    36  42.062   2.527   2.130    .034    .028  55.038  -1.500 100.319
    37  41.657   2.611   2.174    .014   -.010  55.141  -1.500 100.087
    38  42.119   2.421   2.168   -.021    .035  55.192  -1.500 100.414

AVER:   41.940   2.455   2.166    .001    .016  54.953  -1.500 100.032
SDEV:     .259    .096    .026    .041    .020    .167    .000    .282
SERR:     .086    .032    .009    .014    .007    .056    .000
%RSD:      .62    3.91    1.20 4608.25  127.17     .30     .00

PUBL:   41.863   2.472   2.290    n.a.    n.a.  54.874  -1.500 100.000
%VAR:      .18    -.70   -5.40     ---     ---     .14     .00
DIFF:     .077   -.017   -.124     ---     ---    .079    .000
STDS:      211     206     211      42      39     211       0


Without the TDI fit (shown next), F matches the published value a bit more closely, but I think the slope is real so I use the TDI fit.

Halogen corrected
No TDI fit

St  209 Set   1 Apatite APS-27, Results in Oxide Weight Percents

ELEM:     P2O5       F      Cl     MnO     FeO     CaO       O   SUM 
    30  41.506   2.560   2.135    .043    .008  54.988  -3.059  98.179
    31  41.653   2.498   2.192   -.076    .036  54.655  -3.046  97.911
    32  42.263   2.490   2.158    .017   -.004  54.780  -3.035  98.668
    33  42.092   2.462   2.158   -.008   -.009  54.978  -3.024  98.650
    34  41.784   2.477   2.213    .046    .040  54.827  -3.042  98.343
    35  42.035   2.384   2.164   -.039    .019  54.819  -2.992  98.389
    36  42.010   2.475   2.129    .034    .028  55.012  -3.023  98.666
    37  41.604   2.534   2.173    .014   -.010  55.115  -3.057  98.372
    38  42.070   2.464   2.168   -.021    .034  55.165  -3.027  98.853

AVER:   41.891   2.483   2.166    .001    .016  54.926  -3.034  98.448
SDEV:     .261    .049    .026    .041    .020    .167    .021    .292
SERR:     .087    .016    .009    .014    .007    .056    .007
%RSD:      .62    1.99    1.20 4607.13  127.17     .30    -.69

PUBL:   41.863   2.472   2.290    n.a.    n.a.  54.874  -1.500 100.000
%VAR:      .07     .41   -5.42     ---     ---     .09  102.28
DIFF:     .027    .010   -.124     ---     ---    .052  -1.534
STDS:      211     206     211      42      39     211       0


Here is an example from our Durango standard.  The TDI fit uses all but one obviously bad analysis.  Note that the published value shown for F is probably wrong as the halogen site is overfilled.  Other reports show about 3.3-3.4 wt% F.

St   60 Set   1 Apatite (Fluor) Durango, Results in Oxide Weight Percents

ELEM:     P2O5       F      Cl     MnO     FeO     CaO    Na2O    SiO2     SO3   As2O3   La2O3   Ce2O3   Pr2O3   Nd2O3       O   SUM 
    21  41.098   3.102    .441    .017    .042  53.983    .187    .351    .370    .092    .468    .591    .060    .180  -1.400  99.582
    22  40.498   3.544    .421    .029    .022  53.808    .187    .351    .370    .092    .468    .591    .060    .180  -1.582  99.039
    23  40.862   3.298    .429    .023    .012  54.027    .187    .351    .370    .092    .468    .591    .060    .180  -1.480  99.469
    25  40.764   3.894    .414   -.028    .004  54.163    .187    .351    .370    .092    .468    .591    .060    .180  -1.728  99.782
    26  41.244   3.805    .418   -.040    .022  54.051    .187    .351    .370    .092    .468    .591    .060    .180  -1.691 100.108
    27  41.182   3.232    .421    .006   -.005  53.968    .187    .351    .370    .092    .468    .591    .060    .180  -1.451  99.653
    28  40.897   3.409    .430   -.032    .070  53.897    .187    .351    .370    .092    .468    .591    .060    .180  -1.527  99.443
    29  40.300   3.403    .423    .033   -.006  53.974    .187    .351    .370    .092    .468    .591    .060    .180  -1.523  98.904

AVER:   40.856   3.461    .425    .001    .020  53.984    .187    .351    .370    .092    .468    .591    .060    .180  -1.548  99.497
SDEV:     .330    .274    .008    .030    .026    .105    .000    .000    .000    .000    .000    .000    .000    .000    .114    .388
SERR:     .117    .097    .003    .010    .009    .037    .000    .000    .000    .000    .000    .000    .000    .000    .040
%RSD:      .81    7.92    2.00 2774.99  128.99     .19     .00     .00     .00     .00     .00     .00     .00     .00   -7.36

PUBL:   40.881   3.530    .373    n.a.    .054  54.020    .187    .351    .370    .092    .468    .591    .060    .180    .005 101.259
%VAR:     -.06   -1.96   13.87     ---  -62.98    -.07     .00     .00     .00     .00     .00     .00     .00     .00-28754.95
DIFF:    -.025   -.069    .052     ---   -.034   -.036    .000    .000    .000    .000    .000    .000    .000    .000  -1.553
STDS:      211     206     211      42      39     211       0       0       0       0       0       0       0       0       0




The scatter is difficult to work with so I tend to get 7-10 analyses and disable several of them.   Here is another try with more analyses removed.  The F composition is more reasonable.  If I also remove lines 21 and 27, F comes out to 3.35 wt%.

St   60 Set   1 Apatite (Fluor) Durango, Results in Oxide Weight Percents

ELEM:     P2O5       F      Cl     MnO     FeO     CaO    Na2O    SiO2     SO3   As2O3   La2O3   Ce2O3   Pr2O3   Nd2O3       O   SUM 
    21  41.098   3.102    .441    .017    .042  53.983    .187    .351    .370    .092    .468    .591    .060    .180  -1.400  99.582
    23  40.862   3.298    .429    .023    .012  54.027    .187    .351    .370    .092    .468    .591    .060    .180  -1.480  99.469
    27  41.182   3.232    .421    .006   -.005  53.968    .187    .351    .370    .092    .468    .591    .060    .180  -1.451  99.653
    28  40.897   3.409    .430   -.032    .070  53.897    .187    .351    .370    .092    .468    .591    .060    .180  -1.527  99.443

AVER:   41.010   3.260    .430    .003    .030  53.969    .187    .351    .370    .092    .468    .591    .060    .180  -1.465  99.537
SDEV:     .155    .128    .008    .025    .033    .054    .000    .000    .000    .000    .000    .000    .000    .000    .053    .098
SERR:     .078    .064    .004    .012    .017    .027    .000    .000    .000    .000    .000    .000    .000    .000    .027
%RSD:      .38    3.93    1.92  722.05  112.26     .10     .00     .00     .00     .00     .00     .00     .00     .00   -3.62

PUBL:   40.881   3.530    .373    n.a.    .054  54.020    .187    .351    .370    .092    .468    .591    .060    .180    .005 101.259
%VAR:      .32   -7.64   15.38     ---  -45.07    -.10     .00     .00     .00     .00     .00     .00     .00     .00-27215.08
DIFF:     .129   -.270    .057     ---   -.024   -.052    .000    .000    .000    .000    .000    .000    .000    .000  -1.470
STDS:      211     206     211      42      39     211       0       0       0       0       0       0       0       0       0




Here is the log-linear fit.

St   60 Set   1 Apatite (Fluor) Durango, Results in Oxide Weight Percents

ELEM:     P2O5       F      Cl     MnO     FeO     CaO    Na2O    SiO2     SO3   As2O3   La2O3   Ce2O3   Pr2O3   Nd2O3       O   SUM 
    21  41.103   3.445    .441    .017    .042  53.977    .187    .351    .370    .092    .468    .591    .060    .180  -1.545  99.779
    23  40.863   3.404    .429    .023    .012  54.025    .187    .351    .370    .092    .468    .591    .060    .180  -1.525  99.530
    27  41.186   3.504    .421    .006   -.005  53.962    .187    .351    .370    .092    .468    .591    .060    .180  -1.565  99.808
    28  40.899   3.509    .430   -.032    .070  53.895    .187    .351    .370    .092    .468    .591    .060    .180  -1.569  99.501

AVER:   41.013   3.466    .430    .003    .030  53.965    .187    .351    .370    .092    .468    .591    .060    .180  -1.551  99.654
SDEV:     .157    .050    .008    .025    .033    .054    .000    .000    .000    .000    .000    .000    .000    .000    .020    .162
SERR:     .078    .025    .004    .012    .017    .027    .000    .000    .000    .000    .000    .000    .000    .000    .010
%RSD:      .38    1.45    1.92  722.17  112.27     .10     .00     .00     .00     .00     .00     .00     .00     .00   -1.32

PUBL:   40.881  3.530    .373    n.a.    .054  54.020    .187    .351    .370    .092    .468    .591    .060    .180    .005 101.259
%VAR:      .32   -1.83   15.38     ---  -45.07    -.10     .00     .00     .00     .00     .00     .00     .00     .00-28814.16
DIFF:     .132   -.064    .057     ---   -.024   -.056    .000    .000    .000    .000    .000    .000    .000    .000  -1.556
STDS:      211     206     211      42      39     211       0       0       0       0       0       0       0       0       0



As I stated in my previous post, we now use our Durango as a secondary standard.  Ca, P, and Cl tend to come out well most of the time, but F is variable, partly due to TDI fits, but heterogeneity is probably a factor, and our standard could use a new polish too.

Edited by John to make output results use a fixed width font (see the Tt button)

[Brian Joy]

Hi Brian,

How appropriate that you responded – you were my TA at Davis!

Hi Eric,

I was wondering if you were the same Eric Kelly.  Good to hear from you.

By the way, since your F Ka peak is near 85 mm, then you are using LDE1, and the 2d is roughly 60 angstroms.

Brian

[Jeremy Wykes]

Two papers I saw were: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3638812/ and http://journal.chemistrycentral.com/content/7/1/56  Are you guys familiar with chlorapatite prepared in this fashion?     -Marc

I have made an attempt using Klemme et al method, and you can readily produce mm sized crystals. Obviously, the crystal in the paper is the absolute best one they made, so ours did not look quite so nice.