ASTM: D5317: Chlorinated Organic Acids in Water

Summary
Analytes
Revision
Data and Sites

Official Method Name

Standard Test Method for Determination of Chlorinated Organic Acid Compounds in Water by Gas Chromatography with an Electron Capture Detector

Current Revision

Current edition approved Dec. 10, 1998. Originally published as D5317-92.

Media

WATER

Instrumentation

Gas Chromatography with Electron Capture Detection

Method Subcategory

Organic

Method Source

ASTM

Citation

Annual Book of ASTM Standards, Section 11, Water and Environmental Technology, Volume 11.02, Water (I)

Brief Method Summary

The compounds listed in Section 1.1, in water samples, are converted into sodium salts by adjusting the pH to 12 with sodium hydroxide solution (240 g/L) and shaking for 1 h. Extraneous neutral material is removed by extraction with methylene chloride. The sample is acidified, the acids are extracted with ethyl ether and converted to methyl esters using diazomethane. After the excess reagent is removed the methyl esters are determined by capillary column GC using an electron capture (EC) detector. Other detection systems, such as microcoulometric and electrolytic conductivity, are not as sensitive as EC for measurement of chlorinated acid esters but are more specific and less subject to interferences. A mass spectrometer may also be used as a detector.
This test method provides a magnesium silicate cleanup procedure to aid in the elimination of interferences that may be present.

Scope and Application

This test method covers a gas chromatographic procedure for the quantitative determination of selected chlorinated acids and other acidic herbicides in water. Similar chemicals may also be determined by this test method, but it is the user's responsibility to verify the applicability of this test method to any compounds not listed in this scope.

Applicable Concentration Range

From approx 0.5 to 10 except for 2,4-DB which is 8 - 40 ug/L

Interferences

Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing apparatus that lead to discrete artifacts or elevated baselines in gas chromatograms.
The acid forms of the analytes are strong organic acids that react readily with alkaline substances and can be lost during sample preparation. Glassware and glass wool must be acid-rinsed with hydrochloric acid (1 + 9) and the sodium sulfate must be acidified with sulfuric acid prior to use to avoid analyte loses due to adsorption.
Organic acids and phenols, especially chlorinated compounds, cause the most direct interference with the determination. Alkaline hydrolysis and subsequent extraction of the basic sample removes many chlorinated hydrocarbons and phthalate esters that might otherwise interfere with the electron capture analysis.
Interferences by phthalate esters (commonly leached from plastics) can pose a major problem in pesticide analysis when using the ECD.
Carry-over effects are minmized by between-sample of equipment with MTBE.
Matrix interferences may be caused by contaminants that are coextracted from the sample.

Quality Control Requirements

As specified by Practice D 5789, the minimum quality control requirements for the analysis of organic compounds in water are verification of system calibration, verification of control at zero analyte concentration, initial demonstration of proficiency, verification of control at representative analyte concentration, assessment of precision, assessment of bias, and maintenance of interlaboratory traceability. Also, specific to this test method are the determination of surrogate compound recoveries in each sample and blank, monitoring internal standard peak area or height in each sample and blank (when internal standard calibration procedures are being used), and daily assessment of instrument performance.

Sample Handling

Test for the presence of chlorine with potassium iodide-starch test paper previously moistened with dilute acid. Darkening of the test paper indicates the presence of chlorine (and a few other oxidizing materials). Add 80 mg Na₂S₂O₃to the bottle before adding the sample.
After the sample is collected in the bottle containing preservative, seal the bottle and shake vigorously for 1 min. Immediately store the sample at 4^oC away from light until extraction.

Maximum Holding Time

Preservation study results indicate that the analytes (measured as total acid) present in samples are stable for 14 days when stored under these conditions (4).

Relative Cost

Unknown

Sample Preparation Methods

This method has 15 analytes associated with it.

Analyte	Detection Level	Bias	Precision	Spiking Level
2,4,5-T(93-76-5) 2,4,5-T 2,4,5-T Acid 2,4,5-Trichlorophenoxyacetic acid 2,4,5-trichloro-Acetic acid Acetic acid, (2,4,5-trichlorophenoxy)- Dacamine 4D Weedone	0.080 ug/L	93% Rec (ML)	11.00 % RSD (ML)	1.00 ug/L
2,4-D(94-75-7) 2,4-D 2,4-D Acid 2,4-D [acetic acid, (2,4-dichlorophenoxy)-1] 2,4-Dichlorophenoxyacetic acid, salts and este 2,4-Dichlorophenoxyacetic acid, salts and esters Acetic acid, (2,4-dichlorophenoxy)- Hedonal Trinoxol Weed-b-gone	0.200 ug/L	92% Rec (ML)	13.10 % RSD (ML)	3.00 ug/L
2,4-DB(94-82-6) 2,4-DB 2,4-Dichlorophenoxybutyric acid 4-(2,4-Dichlorophenoxy)butyric acid Butanoic acid, 4-(2,4-dichlorophenoxy)- Butoxone Butyrac Butyric acid, 4-(2,4-dichlorophenoxy)- Embutone Legumex Venceweed	0.800 ug/L	99% Rec (ML)	16.00 % RSD (ML)	40.00 ug/L
3,5-Dichlorobenzoic acid(51-36-5) 3,5-DCBA 3,5-Dichlorobenzoic acid Benzoic acid, 3,5-dichloro-	0.061 ug/L	90% Rec (ML)	30.60 % RSD (ML)	1.00 ug/L
5-Hydroxydicamba(7600-50-2) 5-Hydroxydicamba Benzoic acid, 2,5-dichloro-3-hydroxy-6-methoxy Benzoic acid, 2,5-dichloro-3-hydroxy-6-methoxy- Dicamba, 5-hydroxy-	0.040 ug/L	99% Rec (ML)	29.80 % RSD (ML)	1.00 ug/L
Bentazon(25057-89-0) 3-(1-methylethyl)-1H-2,1,3-benzothiadiazin-4(3 Basagran Bendioxide Bentazon Bentazon (ANSI) Bentazone	0.200 ug/L	79% Rec (ML)	17.50 % RSD (ML)	3.00 ug/L
DCPA acid metabolites(E-14028) Chlorthal DCPA Acid Metabolites DCPA Acid Metabolites DCPA Diacid DCPA acid metabolites Dachthal Acid Metabolites Dacthal Acid Metabolites	0.020 ug/L	83% Rec (ML)	20.60 % RSD (ML)	1.00 ug/L
Dicamba(1918-00-9) 3,6-Dichloro-2-methoxybenzoic acid 3,6-Dichloro-o-anisic acid Banex Banlen, Banvel Benzoic acid, 3,6-dichloro-2-methoxy- Dianate Dicamba Dicamba ( 3,6-dichloro-o-anisic acid ) Dicamba (3,6-Dichloro-2-methoxybenzoic acid) Mediban Methoxy-3,6-dichlorobenzoic acid,2-	0.081 ug/L	98% Rec (ML)	9.60 % RSD (ML)	1.00 ug/L
Dichlorprop(120-36-5) 2,4-DP 2-(2,4-Dichlorophenoxy)propionic acid 2[2,4-(Dichlorophenoxy)]-propanoic acid Cornox RK Dichloroprop Dichlorprop Hedonal DP Polytox Propanoic acid, 2-(2,4-dichlorophenoxy)- Propionic acid,2-(2,4-dichlorophenoxy)-	0.260 ug/L	98% Rec (ML)	13.90 % RSD (ML)	4.00 ug/L
Herbicides(E-12839) Herbicide formulations Herbicides	N/A	N/A	N/A
Organics, semivolatile(E-12884) Organics, semivolatile Semi-volatile organics Semivolatile organics	N/A	N/A	N/A
Organochlorine pesticides(E-12851) Organochlorine pesticides Pesticides, organochlorine	N/A	N/A	N/A
Pentachlorophenol(87-86-5) PCP Penchlorol Penta Pentachlorophenol Phenol, pentachloro- Santophen I	0.076 ug/L	87% Rec (ML)	20.40 % RSD (ML)	1.00 ug/L
Picloram(1918-02-1) 2-Pyridinecarboxylic acid, 4-amino-3,5,6-trichloro- 4-Amino-3,5,6-trichloro-2-pyridinecarboxylic a 4-Amino-3,5,6-trichloro-2-pyridinecarboxylic acid 4-Amino-3,5,6-trichloropicolinic acid Amdon Borolin Picloram Picolinic acid,4-amino-3,5,6-trichloro- Tordon	0.140 ug/L	105% Rec (ML)	34.20 % RSD (ML)	2.00 ug/L
Silvex(93-72-1) 2,4,5-TP 2,4,5-TP Acid 2,4,5-Trichlorophenoxypropionic acid 2-(2,4,5-Trichlorophenoxy)propionic acid Fenoprop Propanoic acid, 2-(2,4,5-trichlorophenoxy)- Propionic acid, 2-(2,4,5-trichlorophenoxy)- Silvex Silvex (ANSI)	0.075 ug/L	98% Rec (ML)	14.00 % RSD (ML)	3.00 ug/L

Precision Descriptor Notes:	As specified by Practice D 5789, the minimum quality control requirements for the analysis of organic compounds in water are verification of system calibration, verification of control at zero analyte concentration, initial demonstration of proficiency, verification of control at representative analyte concentration, assessment of precision, assessment of bias, and maintenance of interlaboratory traceability. Also, specific to this test method are the determination of surrogate compound recoveries in each sample and blank, monitoring internal standard peak area or height in each sample and blank (when internal standard calibration procedures are being used), and daily assessment of instrument performance.
Detection Level Note:	Estimated method detection limit, ug/L, determined from 7 replicate analyses of a reagent water fortified with analyte at a concentration level yielding signal-to-noise of 5:1. EDL is defined as the standard deviation x student's t (99 % C.I., n-1 degrees of freedom)

Precision Descriptor Notes:

Detection Level Note:

Estimated method detection limit, ug/L, determined from 7 replicate analyses of a reagent water fortified with analyte at a concentration level yielding signal-to-noise of 5:1. EDL is defined as the standard deviation x student's t (99 % C.I., n-1 degrees of freedom)

Revision	PDF/Link
Current edition approved Dec. 10, 1998. Originally published as D5317-92.

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ASTM: D5317: Chlorinated Organic Acids in Water

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