EPA-RCA: 7580: White Phosphorus in water, soil, and sediment by GC/NPD

Summary
Analytes
Revision
Data and Sites

Official Method Name

White Phosphorus (P4) by Solvent Extraction and Gas Chromatography

Current Revision

December 1996

Media

WATER

Instrumentation

Gas Chromatography with Nitrogen - Phosphorus Detection

Method Subcategory

Inorganic

Method Source

EPA-RCA

Citation

SW-846 Online: Test Methods for Evaluating Solid Waste, Physical/Chemical Methods

Brief Method Summary

Method 7580 may be used to determine the concentration of white phosphorus in soil, sediment, and water samples using solvent extraction and gas chromatography (GC). Water samples are extracted by one of two procedures, depending on the sensitivity required. For the more sensitive procedure, a 500-mL water sample is extracted with 50 mL of diethyl ether. The extract is concentrated by back extraction with reagent water, yielding a final extract volume of approximately 1.0 mL. A 1.0 uL aliquot of this extract is injected into a GC equipped with a nitrogen-phosphorus detector (NPD). This procedure provides sensitivity on the order of 0.01 ug/L. Wet soil or sediment samples are analyzed by extracting a 40 g wet-weight aliquot of the sample with a mixture of 10.0 mL degassed reagent water and 10.0 mL isooctane. The extraction is performed in a glass jar on a platform shaker for 18 hours. A 1.0 uL aliquot of the extract is analyzed by GC-NPD, providing sensitivity on the order of 1 ug/kg.

Scope and Application

Trace analysis of white phosphorous (P4) in water, soil,and sediment samples.

Applicable Concentration Range

Interferences

To date, no chromatographic interferences with this determination have been reported, in part due to the selectivity of the nitrogen-phosphorus detector. This procedure offers several advantages compared to other procedures described in the literature which determine P₄ by converting it to phosphate, in that background concentrations of phosphate are quite common in many water and sediment samples.

Quality Control Requirements

Initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. 10 extracts, the injection of the tenth extract, the mid-point calibration standard must be injected to verify the calibration.

Sample Handling

Maximum Holding Time

5 days suggested

Relative Cost

$51 to $200

Sample Preparation Methods

This method has 1 analyte associated with it.

Analyte	Detection Level	Bias	Precision	Pct False Positive	Pct False Negative	Spiking Level
Phosphorus, mol.(P4)(12185-10-3) Phosphorus molecule Phosphorus tetramer Phosphorus, mol.(P4) Phosphorus, white White phosphorus Yellow phosphorus	0.010 ug/L	89% Rec	19.60 % RSD			0.01 ug/L

Precision Descriptor Notes:	Performance data and detection levels shown are for water samples. To date, only single laboratory performance data have been generated. Those data indicate that there may be problems with the recovery of P₄ from soils containing high concentrations of metals. Therefore, laboratories employing this method are encouraged to develop in-house performance data including MDLs and accuracy and precision data for routinely encountered matrices. These data should be developed in accordance with the procedures outlined in Method 8000.
Detection Level Note:	This method includes two different extraction procedures for water samples. The first procedure provides sensitivity on the order of 0.01 µg/L, and may be used to assess compliance with Federal water quality criteria. The second procedure provides sensitivity on the order of 0.1 µg/L. The method includes one procedure for the extraction of soil/sediment samples which provides sensitivity on the order of 1 µg/kg.

Precision Descriptor Notes:

Performance data and detection levels shown are for water samples.

To date, only single laboratory performance data have been generated. Those data indicate that there may be problems with the recovery of P₄ from soils containing high concentrations of metals. Therefore, laboratories employing this method are encouraged to develop in-house performance data including MDLs and accuracy and precision data for routinely encountered matrices. These data should be developed in accordance with the procedures outlined in Method 8000.

Detection Level Note:

This method includes two different extraction procedures for water samples. The first procedure provides sensitivity on the order of 0.01 µg/L, and may be used to assess compliance with Federal water quality criteria. The second procedure provides sensitivity on the order of 0.1 µg/L. The method includes one procedure for the extraction of soil/sediment samples which provides sensitivity on the order of 1 µg/kg.

Revision	PDF/Link
December 1996

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EPA-RCA: 7580: White Phosphorus in water, soil, and sediment by GC/NPD

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