『Abstract
　Five different methods commonly used for the extraction and the determination of iron hydroxides and/or the associated phosphorus held in marine seston or in sediments have been tested on single-phase minerals (goethite and apatite), on reference minerals (SO1 and SO2), and on suspended-matter samples from the St. Lawrence Estuary and from the estuary of the Eastmain River, a major James Bay affluent in northern Quebec, Canada.
　The citrate-dithionite - bicarbonate (CDB) procedure generally seemed to be more reproducible and more specific. The validity of the other methods respectively using as extracting reagents ammonium oxalate - oxalic acid, hydroxylamine hydrochloride, calcium nitrilotriacetic acid and acetate - tartrate is discussed.
　The CDB extraction is included in an analytical scheme which allows to distinguish between three fractions of phosphorus. This chemical speciation is applied to the study of P retention on Fe-hydroxides, and to its potential desorption.』

1. Introduction
2. Laboratory experiments
3. Results
4. Proposed extraction sequence
5. Conclusion and applications
Acknowledgements
References

図1．リンと鉄の異なる画分の決定のために提案された連続抽出法．（１）原子吸光分析、（２）Harwood et al.（1969）の比色分析、（３）Watanabe and Olsen（1962）の比色分析．（元は図）

〔CDB＝citrate（クエン酸塩）-dithionite（亜ジチオン酸）-bicarbonate（炭酸水素塩、重炭酸塩）〕

			0.5 g
Pex（２）←			交換可能 1M 酢酸アンモニウム（ammonium acetate）、 pH＝8.5	→Feex（１）
0.25 g←				→0.25 g
PCDB（３）	オキシ水酸化物 CDB	FeCDB（１）		全　Fetot（１） HF-HNO3-HClO4-HCl
PAp（２）	アパタイト 1N HCｌ（塩酸）
Porg（２）	全／有機 550℃／1N HCｌ（塩酸）
Ptot＝Pex＋PCDB＋PAp＋Porg				Fetot−FeCDB＝Felith