Hello Clemente,
In addition to the references Maura listed, it would
be worth checking out the 'rapid' Ag3PO4 precipitation
method described by Matt Kohn in the data repository
section of the following paper:

DETTMAN, D. L., KOHN, M. J., QUADE, J., RYERSON, F.
J., OJHA, T. P. & HAMIDULLAH, S. (2001) Seasonal
stable isotope evidence for a strong Asian monsoon
throughout the past 10.7 m.y. Geology, 29, 31-34.

It is very quick compared with previous methods
(minutes vs hours) and can be easily scaled to
precipitate small (<5mg) biogenic phosphate samples.

Take care,
Vaughan
  
--- Maura Pellegrini <[log in to unmask]> wrote:

> Dear Clemente,
> some of most important and basic references in the
> subject are:
> 
> F.H. Firsching, Precipitation of silver phosphate
> from homogeneous
> solution, Analytical Chemistry 33, 873-874, 1961.
> 
> J.R. O'Neil, L.J. Roe, E. Reinhard and R.E. Blake, A
> rapid and precise
> method of oxygen isotope analysis of biogenic
> phosphate, Israel Journal of
> Earth Sciences 43, 203-212, 1994.
> 
> A.P. Tudge, A method of analysis of oxygen isotopes
> of orthophosphates: its
> use in the measurements of paleotemperatures,
> Geochimica et Cosmochimica
> Acta 18, 81-93, 1960.
> 
> R.A. Crowson, W.J. Showers, E.K. Wright and T.C.
> Hoering, Preparation of
> phosphate samples for oxygen isotope analysis,
> Analitical Chemistry 63,
> 2379-2400, 1991.
> 
> T.W. Vennemann, H.C. Fricke, R.E. Blake, J.R. O'Neil
> and A. Colman, Oxygen
> isotope analysis of phosphates: a comparison of
> techniques for analysis of
> Ag3PO4, Chemical Geology 185(3-4), 321-336, 2002.
> 
> 
> Somebody told me about a new, even faster recent
> method, but I haven't got
> the reference. 
> In our lab, we have most been using amberlite for
> phosphate extraction from
> bones and teeth. You can contact us off-line if you
> wish more detailed
> information about lab procedures.
> 
> Maura
> 
> 
> 
> At 13.10 21/02/06 +0100, you wrote:
> >Dear Colleagues,
> >
> >A student is about to begin Ph.D work involving 
> >analysis of , among other things, biogenic 
> >phosphates.  We have prior experience in the 
> >analysis of O in phosphates for other 
> >researchers, but samples were always sent to us 
> >ready for analysis.
> >
> >Searching the archives yielded lots of postings 
> >on the subject, but none directed us to a step by 
> >step method for converting biogenic phosphate 
> >into say Ag3PO4. Methodological papers (for 
> >example, that in Pier de Groot's book, to mention 
> >just a recent one) are not detailed enough for 
> >newcomers (this is not a criticism; it is just 
> >impossible to go beyond a certain level of detail 
> >in a published work ...).
> >
> >Will you care to recommend any article, web site, 
> >book, ... where we could find a "recipe" for 
> >sample treatment and phosphate isolation for 
> >O-isotopic analysis? If you have your own method, 
> >will you mind sharing it with us? As an example, 
> >the description of Nitrate isolation from waters 
> >in the web page by C. Kendal's group of the USGS 
> >(after articles of Silva et al., Chang et al., 
> >...) was most helpful. Is there anything similar 
> >for phosphates?
> >
> >Thanks,
> >
> >Clemente
> >
> >
> >-- 
> >
> >
> >*******************************************
> >Dr. Clemente Recio
> >Laboratorio de Isótopos Estables
> >Fac. de Ciencias
> >Univ. de Salamanca
> >Plaza de la Merced, S/N
> >E-37008 SALAMANCA
> >               SPAIN
> >
> >Phone: (+34) 923 29 45 00, Ext. 1540 (Automatic
> Switchboard)
> >Fax:     (+34) 923 29 45 14
> >E-mail: [log in to unmask]
> >Web page: http://www.usal.es/isotopos
> >*******************************************
> >
> 
> 
> 
> Dr Maura Pellegrini 
> 
> PhD Isotope Geochemistry
> Dipartimento di Scienze della Terra
> (Earth Sciences Department)
> Università di Parma
> Parco Area delle Scienze 157/A 
> 43100 Parma Italy
> 
> FAX ++39 (0)521 905305
> Tel ++39 (0)521 905312
> 



	

	
		
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