Literature

Improving SPE disk extraction technology for US EPA wastewater method 625.1

Written by Biotage | Dec 6, 2025 3:15:00 AM

Step

Operation

Solvent

Solvent Vol. (mL)

Purge Time (s)

Pump Rate (#)

N2 Blanket

Sat. Time (s)

Soak Time (s)

Elute Time (s)

Introduction


The US EPA monitors a variety of chemicals in water that may cause harm to humans or wildlife in order to minimize exposure. Method 625 was developed by the Office of Science and Technology in the Clean Water program to monitor a large suite of
semi volatile chemicals in wastewater for compliance with the National Pollution Discharge Elimination System (NPDES). NPDES is a system of permitting that regulates the characteristics of water that is released into a waterway, defined by industrial category. The permitting levels are set depending on the waterway’s use. If the waterway is used for recreation or is an important wildlife habitat, the limit may be set lower.


The original method was developed in the early 1980s and has been updated several times since then to allow for the use of more modern technology. The latest update has taken place over the last few years and was proposed in a Method Update Rule (MUR) in 2015.1 The latest version of the method includes a larger suite of analytes (up to 364) and an extensive set of labelled surrogates to better monitor the method performance throughout sample preparation and analysis steps.2


This note examines the results from an initial demonstration of capability (DOC) with one litre samples utilizing automated disk solid phase extraction (SPE) for US EPA method 625.1. Samples were evaluated and measured against the criteria listed in Table 6 of method 625.1. The analytes chosen for evaluation were from Tables 1, 2 and 3 in Method 625.1. Analytes from Table 3 do not have any acceptance criteria for comparison.
 

Experimental


One litre samples were processed as laboratory control samples (LCS), matrix spike (MS), matrix spike duplicate (MSD) and calibration verifications were evaluated. The samples were extracted using an Atlantic® One-pass SPE disk (Biotage) which is a mixed mode disk containing several functionalities. The process was automated with the Biotage® Horizon 5000 (previously known as the SPE-DEX® 5000) extraction system. A carbon cartridge (Max Detect, Biotage) was also used to ensure adequate retention of the light end compounds, such as N-Nitrosodi-n-propylamine.


The Fast Flow Disk Holder (FFSDH) was used with the samples because this method is known for varying levels of particulate matter and the sample size was 1 L. The FFSDH uses a 47 mm disk, but allows larger filters to be placed on top to shield the SPE disk from particulates that may cause clogging and maintain fast flow through the disk.
The particulate material is retained on the filters and washed with solvent during the elution step, so any material that has been absorbed on the surface will be included in the extraction. Figure 1 shows a photo of the Biotage® Horizon 5000 configured with the One Pass kit, Carbon Cartridge and the Fast Flow Disk Holder.



Figure 1. Biotage® Horizon 5000 (Previously known as the SPE-DEX 5000 Extractor).

 

The resulting extracts were dried using DryDisk® membrane drying system (Biotage) and evaporated to 1 mL with the DryVap™* Automated In-line Drying and Concentration System (Biotage). The DryVap™ was chosen for its ability to in-line dry and concentrate extracts at a very low boiling point. Those two features preserve the extracted compounds concentration throughout the drying and concentration process, compared to traditional multistep processes. Figure 2 shows the DryVap™ system with DryDisk glassware holding the drying membranes in front. The dried extract is drawn into the concentration tube in the back and the evaporation occurs there. Residual water remains in the front reservoirs separated from the extract.

The extraction method used with the Biotage® Horizon 5000 is shown in Table 1. The conditions for operating the DryVap™ are shown in Table 2.

*The DryVap™ system has been discontinued. We recommend using the TurboVap® evaporation systems for achieving equivalent results.

Figure 2. DryVap™ System.

 

Table 1. Biotage® Horizon 5000 Extraction Method.

Step

Operation

Message

Attachment

1

Pause with message

Part 1 of 3: Neutrals and Acids Elution. Have the Fast Flow Sediment Disk Holder with OnePass Disk, 1 µm filter, 5 µm filter, top screen over the filters, 250 mL collection flask, and carbon cartridge installed. The down spout of the water in valve must push down on the top screen. Click “Continue” to start Part 1.

None

Step

Operation

Solvent

Solvent Vol. (mL)

Purge Time (s)

Pump Rate (#)

Sat. Time (s)

Soak Time (s)

Drain Time (s)

2

Condition SPE

Acetone

40

60

4

2

60

60

3

Condition SPE

Reagent Water

20

60

4

2

60

60

Step

Operation

Sample Flow Rate (#)

Done Loading SampleDelay (s)

 

4

Load Sample

5

45

 

 

 

 

 

Step

Operation

Solvent

Solvent Vol. (mL)

Purge Time (s)

Pump Rate (#)

N2 Blanket

Sat. Time (s)

Soak Time (s)

Drain Time (s)

5

Wash Sample Container

Reagent Water

20

30

4

Off

2

5

30

Step

Operation

 

Dry Time (s)

Pump Rate (#)

N2 Blanket

 

 

 

 

6

Air Dry Disk Timer

 

360

6

Off

 

Step

Operation

Solvent

Solvent Vol. (mL)

Purge Time (s)

Pump Rate (#)

N2 Blanket

Sat. Time (s)

Soak Time (s)

Elute Time (s)

7

Elute Sample Container

Acetone

20

20

4

Off

2

180

180

8

Elute Sample

Container

MeCl2

17

15

4

Off

2

180

180

9

Elute Sample

Container

MeCl2

17

15

4

Off

2

120

120

10

Elute Sample

Container

MeCl2

17

15

4

Off

2

120

120

11

Elute Sample

Container

MeCl2

17

15

6

Off

2

120

180

Step

Operation

Message

Attachment

12

Pause with Message

Part 2 of 3: Ion Exchange Elution. Remove the 250 mL collection flask containing the neutrals and acids elution. Stopper the flask and set aside for part 3. Then install a clean 125 mL flask to collect the ion exchange elution. Click “Continue” to Start Part 2.

None

Step

Operation

Solvent

Solvent Vol. (mL)

Purge Time (s)

Pump Rate (#)

N2 Blanket

Sat. Time (s)

Soak Time (s)

Elute Time (s)

13

Elute Sample Container

Acetone

20

20

4

Off

2

0

180

14

Elute Sample Container

1% NH4OH

20

30

4

Off

2

120

120

15

Elute Sample Container

Acetone

20

20

4

Off

2

180

120

16

Elute Sample Container

MeCl2

17

15

4

Off

2

180

180

17

Elute Sample Container

MeCl2

16

15

4

Off

2

120

180

18

Elute Sample Container

MeCl2

16

15

4

Off

2

120

180

19

Elute Sample Container

MeCl2

16

15

6

Off

2

120

180

Step

Operation

Message

Attachment

20

Pause with Message

Part 3 of 3: Carbon Cartridge Elution. Remove the carbon cartridge from the tubing lines. Connect the tubing ends together. Using a 20 cc syringe, plunge the carbon cartridge with air through the cap adapter to reseat the carbon bed on the frit. Replace the cap adapter with the funnel cartridge. Replace the disk holder with the cartridge. Replace the 125 mL flask with the 250 mL flask containing the neutrals and acids elution from Part 1. Stopper the 125 mL flask. Click “Continue” to start part 3.

None

Step

Operation

Dry Time (s)

Pump Rate (#)

N2

Blanket

 

 

 

 

21

Air Dry Disk Timer

60

6

Off

 

 

 

 

Step

Operation

Solvent

Solvent Vol. (mL)

Purge Time (s)

Pump Rate (#)

N2 Blanket

Sat. Time (s)

Soak Time (s)

Elute Time (s)

22

Elute Sample Container

Acetone

25

20

4

Off

3

60

60

23

Elute Sample Container

MeCl2

17

15

4

Off

3

60

20

24

Elute Sample Container

MeCl2

17

15

4

Off

3

60

20

25

Elute Sample Container

MeCl2

17

15

4

Off

3

60

20

26

Elute Sample Container

MeCl2

17

15

4

Off

3

60

20

27

Elute Sample Container

MeCl2

17

15

6

Off

3

60

60

 

The samples were measured using GC/MS (6890GC/5975CMS, Agilent Technologies). The operational conditions are shown in Table 3.
All spiking standards used were from (Supelco, Bellefonte, PA). The surrogate mixes were from (Restek Corp, Bellefonte, PA.).

Table 2. DryVap™ System Conditions.

Parameter

Setting

Dry Volume

200 mL

Heat Power

5

Heat Timer

OFF

Auto Rinse Mode

OFF

Nitrogen Sparge

20 psi

Vacuum

-7 in. Hg


Table 3. GC/MS Conditions.

Injection

 

Volume

1 µL

Inlet Temperature

280 °C

Mode

Splitless

Gas Type

Helium

Cartridge

Zebron™ ZB-Semi volatiles (Phenomenex)

Mode

Consistent Flow

Oven Program

45 °C hold for 1 min to 270 °C at 15 °C/min then to 318 °C at 6 °C/min

MS Ions Monitored

Scan masses 35–550

Results and discussion


Table 6 in US EPA Method 625.1 (December 2014) lists criterion by analytes for a variety of characteristics to validate that the method applied with changes will meet the requirements of the original method for a variety of challenging matrices; representative of those that may be encountered in a commercial laboratory. This table is included in Appendix 1 for easy reference.
The first cartridge of Table 6 in Method 625.1 is range in % for recovery of the calibration verification standard. The results for this standard during the testing of the extracts is shown in Table 4 and meets the criteria listed in Method 625.1
for compliance.

 

Table 4. Calibration Verification over the Course of Operation.

Analyte

Recovery (%)

Recovery (%)

Recovery (%)

Recovery (%)

Recovery (%)

Recovery (%)

Range for Q (%)

Pass/Fail

NDMA

102.9

94.4

96.9

97.8

97.6

94.1

60-140

Pass

1,2,4,5-

Tetrachlorobenzene

98.0

97.5

95.0

101.9

100.8

97.2

60-140

Pass

1,2,4-Trichlorobenzene

97.7

98.4

95.0

101.2

100.9

97.2

61-130

Pass

1,3,5,-Trinitrobenzene

95.5

94.7

92.1

97.1

94.6

92.8

60-140

Pass

1,4-Naphthoquinone

94.8

94.7

92.6

97.9

95.4

92.0

60-140

Pass

1-Naphthylamine

85.5

82.6

82.8

87.8

82.6

82.4

60-140

Pass

2,3,4,6-

Tetrachlorophenol

93.9

93.5

93.5

98.1

96.3

93.6

60-140

Pass

2,4,5-Trichlorophenol

95.1

94.8

93.9

99.2

95.9

93.0

60-140

Pass

2,4-Dichlorophenol

96.7

96.2

94.4

99.5

96.3

93.1

64-130

Pass

2,4-Dimethylphenol

98.0

97.9

95.2

99.9

97.2

93.8

58-130

Pass

2,4-Dinitrophenol

80.2

81.2

85.7

87.9

85.6

82.1

39-173

Pass

2,4-Dinitrotoluene

93.5

94.2

94.0

98.6

96.9

93.9

53-130

Pass

2,6-Dichlorophenol

95.8

96.5

94.9

99.2

96.3

93.7

60-140

Pass

2,6-Dinitrotoluene

94.5

94.3

92.6

98.9

96.3

93.5

68-137

Pass

2-Chloronaphthalene

97.8

97.4

94.7

100.2

99.6

96.0

70-130

Pass

2-Chlorophenol

97.4

96.6

94.6

98.9

99.2

94.7

55-130

Pass

2-Fluorobiphenyl

99.0

97.9

97.3

100.0

92.5

91.0

60-140

Pass

2-Fluorophenol

99.9

95.8

97.8

95.4

96.3

94.3

60-140

Pass

2-Methylnaphthalene

96.7

98.4

95.3

100.5

98.8

95.3

60-140

Pass

2-Naphthylamine

68.6

70.4

66.2

71.8

65.5

66.7

60-140

Pass

2-Nitroaniline

95.1

94.3

93.4

98.1

94.9

92.5

60-140

Pass

2-Nitrophenol

95.2

96.5

93.7

98.2

96.1

93.7

61-163

Pass

3,3'-Dichlorobenzidine

107.2

106.0

100.4

108.2

102.7

102.2

18-213

Pass

3,3'-Dimethylbenzidine

80.2

84.5

80.1

92.8

86.1

88.0

60-140

Pass

3-Methylcholanthrene

95.0

96.1

92.4

99.4

95.9

94.4

60-140

Pass

3-Nitroaniline

99.2

96.0

96.2

100.6

97.8

96.1

60-140

Pass

4 Aminobiphenyl

87.9

88.2

79.6

86.2

79.9

80.4

60-140

Pass

4,6-Dinitro-2- methylphenol

89.0

90.5

90.9

96.2

94.0

90.7

56-130

Pass

4-Bromophenyl phenyl ether

96.6

99.8

96.0

103.5

100.8

98.1

70-130

Pass

4-Chloro-3- methylphenol

94.8

96.5

95.2

97.7

96.0

91.9

68-130

Pass

4-Chloroaniline

74.7

86.9

75.3

87.5

85.3

82.5

60-140

Pass

4-Chlorophenyl phenyl ether

95.3

97.9

94.9

101.0

98.8

97.5

57-145

Pass

4-Nitroaniline

96.3

92.4

94.9

94.6

94.6

89.9

60-140

Pass

4-Nitrophenol

96.4

89.3

91.5

91.7

90.0

86.8

35-130

Pass

4-Nitroquinoline-1- oxide

89.7

95.9

87.2

104.1

94.4

101.0

60-140

Pass

5-nitro-o-toluidine

94.3

92.9

92.7

98.6

96.3

93.5

60-140

Pass

Analyte

Recovery (%)

Recovery (%)

Recovery (%)

Recovery (%)

Recovery (%)

Recovery (%)

Range for Q (%)

Pass/Fail

7,12-Dimethylbenz(a)- anthracene

94.6

98.2

95.0

100.2

98.8

95.1

60-140

Pass

Acenaphthene

97.1

96.7

94.6

100.4

97.7

95.0

70-130

Pass

Acenaphthylene

96.9

96.5

94.6

100.5

97.2

94.6

60-130

Pass

Acetophenone

96.7

96.7

94.2

100.0

99.0

95.2

60-140

Pass

Acetylaminofluorene

97.0

95.8

92.1

98.5

94.4

93.7

60-140

Pass

Aniline

90.6

90.6

91.0

96.9

93.3

93.1

60-140

Pass

Anthracene

98.1

98.0

94.5

100.1

98.6

95.0

58-130

Pass

Benz(a)anthracene

96.6

95.1

94.1

98.2

97.2

94.3

42-133

Pass

Benzidine

81.9

84.7

76.3

87.4

82.0

85.3

60-140

Pass

Benzo(a)pyrene

96.5

96.0

93.7

99.3

97.1

94.7

32-148

Pass

Benzo(b)fluoranthene

93.7

94.6

92.2

98.2

96.2

93.2

42-140

Pass

Benzo(ghi)perylene

96.4

93.8

91.3

97.1

92.8

91.1

13-195

Pass

Benzo(k)fluoranthene

97.5

99.3

97.7

101.1

100.2

96.6

25-146

Pass

Benzoic acid

93.6

89.8

92.1

92.9

87.5

86.7

60-140

Pass

Benzyl alcohol

97.1

96.5

94.3

99.1

97.4

94.6

60-140

Pass

Bis(2- chlorethoxy)methane

96.7

98.9

94.3

100.6

98.4

95.5

52-164

Pass

Bis(2-chloroethyl)ether

99.6

99.8

94.7

100.1

99.1

96.5

60-140

Pass

Bis(2chloroisopropyl)et her

95.7

98.8

94.0

102.1

99.7

98.4

63-139

Pass

Bis(2-ethylhexyl) phthalate

85.3

98.6

91.0

102.3

99.9

98.4

43-137

Pass

Carbazole

100.0

96.6

95.1

98.2

97.6

93.5

60-140

Pass

Chrysene

97.4

96.1

94.8

98.1

97.6

93.9

44-140

Pass

Dibenz(ah)anthracene

91.2

93.5

91.1

98.2

94.2

92.5

13-200

Pass

Dibenzofuran

97.0

96.4

94.8

100.7

98.4

95.1

60-140

Pass

Diethyl phthalate

92.5

96.3

93.3

101.4

98.5

97.0

47-130

Pass

Dimethyl phthalate

93.7

95.7

93.3

99.4

97.4

94.4

50-130

Pass

Dimethylaminoazoben- zene

90.2

97.7

93.3

99.5

97.9

95.5

60-140

Pass

Di-n-butyl phthalate

90.9

100.1

91.1

101.8

100.8

98.7

52-130

Pass

Di-n-octyl phthalate

89.3

99.2

92.2

102.3

99.4

98.4

21-132

Pass

Dinoseb

89.8

94.1

90.0

98.5

97.1

94.2

60-140

Pass

Diphenylamine

96.2

96.3

95.3

99.4

97.9

95.3

60-140

Pass

Ethylmethane Sul-

fonate

96.8

95.2

94.8

98.6

97.9

95.9

60-140

Pass

Fluoranthene

98.4

96.9

94.8

97.4

97.7

95.1

47-130

Pass

Fluorene

95.6

96.5

93.9

99.4

98.5

94.8

70-130

Pass

Hexachlorobenzene

96.1

99.6

94.4

101.3

99.4

96.2

38-142

Pass

Hexachlorobutadiene

97.9

101.3

95.5

104.7

103.5

100.3

68-130

Pass

Hexachlorocyclopenta- diene

89.9

92.4

88.2

99.4

96.7

94.2

60-140

Pass

Analyte

Recovery (%)

Recovery (%)

Recovery (%)

Recovery (%)

Recovery (%)

Recovery (%)

Range for Q (%)

Pass/Fail

Hexachloroethane

97.9

100.3

93.8

102.9

102.9

100.7

55-130

Pass

Hexachloropropene

97.5

98.9

93.8

101.4

100.6

97.1

60-140

Pass

Indeno(1,2,3-cd)pyrene

94.3

93.3

89.6

95.2

90.8

88.6

13-151

Pass

Isophorone

95.6

98.8

93.8

100.1

98.0

95.1

52-180

Pass

Methapyrilene

90.2

94.0

89.5

97.1

94.8

92.9

60-140

Pass

Naphthalene

98.5

97.9

95.0

100.2

98.8

95.6

70-130

Pass

 

Before running samples, the laboratory must first demonstrate their capability to use a method with an initial DOC, running four spiked reagent water samples through the complete sample preparation and analysis step. The results for recovery accuracy and precision are compared with the range specified for compliance. The range is included in Table 5 for easy comparison. Analytes with a * indicate that they are from Table 3 and do not have acceptance criteria in Table 6 within Method 625.1. It is up to the laboratory to generate their own acceptance criteria for Table 3 analytes.


Table 5. Initial demonstration of compliance.

Analyte

Average DOC

DOC Range

Pass/ Fail

SD

Limit for s (%)

Pass/ Fail

1,2,4,5-Tetrachlorobenzene*

61.89

 

 

5.24

 

 

1,2,4-Trichlorobenzene

57.69

57-130

Pass

5.08

30

Pass

1,2-Dichlorobenzene*

51.60

 

 

4.49

 

 

1,3,5,-Trinitrobenzene*

83.54

 

 

6.65

 

 

1,3-Dichlorobenzene*

46.37

 

 

4.58

 

 

1,3-Dinitrobenzene*

88.29

 

 

5.80

 

 

1,4-Dichlorobenzene*

48.39

 

 

4.84

 

 

1,4-Naphthoquinone*

77.21

 

 

2.15

 

 

1-Naphthylamine*

89.88

 

 

1.58

 

 

2,3,4,6-Tetrachlorophenol*

87.10

 

 

5.02

 

 

2,4,5-Trichlorophenol*

84.55

 

 

4.56

 

 

2,4-Dichlorophenol

86.09

53-122

Pass

4.45

30

Pass

2,4-Dimethylphenol

85.77

42-120

Pass

4.31

35

Pass

2,4-Dinitrophenol

83.62

D-173

Pass

5.97

79

Pass

2,4-Dinitrotoluene

88.97

48-127

Pass

4.91

25

Pass

2,6-Dichlorophenol*

85.58

 

 

4.19

 

 

2,6-Dinitrotoluene

89.83

68-137

Pass

5.49

29

Pass

2-Chloronaphthalene

70.88

65-120

Pass

5.97

15

Pass

2-Chlorophenol

77.07

36-120

Pass

5.10

37

Pass

2-Fluorobiphenyl*

83.45

 

 

2.46

 

 

2-Fluorophenol*

55.75

 

 

6.09

 

 

2-Methyl phenol*

80.66

 

 

5.19

 

 

2-Methylnaphthalene*

68.80

 

 

5.49

 

 

2-Naphthylamine*

109.87

 

 

6.08

 

 

Analyte

Average DOC

DOC Range

Pass/ Fail

SD

Limit for s (%)

Pass/ Fail

2-Nitroaniline*

87.96

 

 

6.80

 

 

2-Nitrophenol

75.83

45-167

Pass

3.66

79

Pass

2-Picoline*

47.44

 

 

2.09

 

 

3,3'-Dichlorobenzidine

88.90

8-213

Pass

3.25

65

Pass

3,3'-Dimethylbenzidine*

94.17

 

 

2.61

 

 

3+4 Methyl phenol*

82.47

 

 

6.41

 

 

3-Methylcholanthrene*

84.77

 

 

5.18

 

 

3-Nitroaniline*

91.89

 

 

4.77

 

 

4 Aminobiphenyl*

112.58

 

 

6.89

 

 

2-methyl-4,6-Dinitrophenol

87.21

53-130

Pass

5.66

122

Pass

4-Bromophenyl phenyl ether

82.74

65-120

Pass

4.84

26

Pass

4-Chloro-3-methylphenol

89.01

41-128

Pass

4.86

44

Pass

4-Chloroaniline*

118.22

 

 

8.03

 

 

4-Chlorophenyl phenyl ether

79.56

38-145

Pass

4.55

36

Pass

4-Nitroaniline*

86.93

 

Pass

4.82

 

 

4-Nitrophenol

92.06

13-129

Pass

4.99

79

Pass

4-Nitroquinoline-1-oxide*

90.69

 

 

7.66

 

 

5-nitro-o-toluidine*

93.58

 

 

5.44

 

 

7,12-Dimethylbenz(a)-anthracene*

84.98

 

 

4.36

 

 

Acenaphthene

76.24

60-132

Pass

5.58

29

Pass

Acenaphthylene

77.33

54-126

Pass

5.81

45

Pass

Acetophenone*

75.52

 

 

3.75

 

 

Acetylaminofluorene*

90.49

 

 

6.10

 

 

Aniline*

80.22

 

 

6.18

 

 

Anthracene*

85.84

43-120

Pass

6.38

40

Pass

Azobenzene*

82.72

 

 

4.95

 

 

Benz(a)anthracene

86.41

42-133

Pass

5.20

32

Pass

Benzidine*

99.72

 

 

4.45

 

 

Benzo(a)pyrene

86.46

32-148

Pass

5.17

43

Pass

Benzo(b)fluoranthene

87.03

42-140

Pass

4.62

43

Pass

Benzo(ghi)perylene

87.07

D-195

Pass

6.09

61

Pass

Benzo(k)fluoranthene

86.62

25-146

Pass

4.91

38

Pass

Benzoic acid*

57.15

 

 

6.57

 

 

Benzyl alcohol*

78.97

 

 

3.41

 

 

Bis(2-chlorethoxy)methane

82.26

49-165

Pass

3.42

32

Pass

Bis(2-chloroethyl)ether

68.31

43-126

Pass

2.05

65

Pass

Bis(2chloroisopropyl)ether

68.10

63-139

Pass

3.03

46

Pass

Bis(2-ethylhexyl) phthalate

91.34

29-137

Pass

6.66

50

Pass

Benzyl butyl phthalate

90.69

D-140

Pass

5.14

36

Pass

Carbazole*

89.33

 

 

7.42

 

 

Chrysene

87.54

44-140

Pass

5.42

53

Pass

cis-Isosafrole*

75.74

 

 

4.98

 

 

Analyte

Average DOC

DOC Range

Pass/ Fail

SD

Limit for s (%)

Pass/ Fail

Dibenz(ah)anthracene

87.88

D-200

Pass

4.85

75

Pass

Dibenzofuran*

78.22

 

 

5.60

 

 

Diethyl phthalate

90.84

D-120

Pass

4.45

60

Pass

Dimethyl phthalate

89.80

D-120

Pass

4.36

110

Pass

Dimethylaminoazobenzene*

91.85

 

 

4.54

 

 

Di-n-butyl phthalate

90.70

8-120

Pass

6.31

28

Pass

Di-n-octyl phthalate

89.40

19-132

Pass

5.25

42

Pass

Dinoseb*

87.13

 

 

6.29

 

 

Diphenylamine*

87.58

 

 

5.24

 

 

Ethylmethane Sulfonate*

75.62

 

 

3.61

 

 

Fluoranthene

87.77

43-121

Pass

6.82

40

Pass

Fluorene

81.07

70-120

Pass

5.80

23

Pass

Hexachlorobenzene

83.49

8-142

Pass

5.44

33

Pass

Hexachlorobutadiene

44.63

38-120

Pass

4.47

38

Pass

Hexachlorocyclopentadiene*

41.53

 

 

4.33

 

 

Hexachloropropene*

45.64

 

 

4.68

 

 

Indeno(1,2,3-cd)pyrene

85.73

D-151

Pass

5.28

60

Pass

Isophorone

82.02

47-180

Pass

3.88

56

Pass

Methapyrilene*

89.82

 

 

4.64

 

 

Methyl Methane Sulfonate*

49.04

 

 

2.10

 

 

Naphthalene

66.73

36-120

Pass

5.59

39

Pass

NDMA*

36.34

 

 

0.68

 

 

Nitrobenzene

72.65

54-158

Pass

3.72

37

Pass

Nitrobenzene-d5

77.26

15-314

Pass

4.08

 

 

N-Nitroso-diethylamine*

67.44

 

 

2.70

 

 

N-nitroso-di-n-butylamine*

85.87

 

 

4.26

 

 

N-nitroso-di-n-propylamine

79.49

14-198

Pass

4.52

52

Pass

N-Nitrosomethyl ethylamine

58.95

 

 

1.50

 

 

N-Nitroso-morpholine*

78.99

 

 

7.92

 

 

N-Nitroso-piperidine*

82.98

 

 

3.96

 

 

N-Nitroso-pyrrolidine*

83.07

 

 

4.02

 

 

o-toluidine*

95.47

 

 

6.77

 

 

Pentachlorobenzene*

74.93

 

 

5.07

 

 

Pentachloroethane*

49.71

 

 

4.29

 

 

Pentachloronitrobenzene*

85.84

 

 

5.93

 

 

Pentachlorophenol

88.93

38-152

Pass

7.50

52

Pass

Phenacetin*

89.68

 

 

6.07

 

 

Phenanthrene

86.11

65-120

Pass

6.78

24

Pass

Phenol

57.80

17-120

Pass

4.35

39

Pass

Analyte

Average DOC

DOC Range

Pass/ Fail

SD

Limit for s (%)

Pass/ Fail

 

Phenol-d5

 

57.80

 

8-424

 

Pass

 

4.35

 

 

p-Terphenyl-d14*

91.52

 

 

4.98

 

 

Pyrene

87.34

70-120

Pass

7.55

30

Pass

Pyridine*

32.13

 

 

2.96

 

 

Safrole*

78.46

 

 

5.28

 

 

trans-Isosafrole*

77.99

 

 

5.67

 

 

The criteria were met in all cases within the demonstrated Table 6 analytes in Method 625.1, indicating the analyte list is under control and further analysis can proceed.

 

Table 6 demonstrates the results for the matrix spike (MS) and matrix spike duplicate (MSD). The spike recovery data from the sample is shown in the second cartridge, where the range criteria shown in Table 6 of Method 625.1 is presented. The spike and surrogates were added at 100 µg/mL in each litre of sample. The relative percent difference between the spike recovery and spike recovery duplicate is calculated using the equation in Method 625.1. If the data meets the criterion, a pass is indicated in the Pass/Fail. Analytes with a * indicate that they are from Table 3 and do not have acceptance criteria in Table 6 within Method 625.1. It is up to the laboratory to generate their own acceptance criteria for Table 3 analytes.

 

Table 6. Recovery Data: Matrix spike (MS) and matrix spike duplicate (MSD).

Analyte

Average MS, MSD Recovery %

Range P,Ps %

Pass/Fail

RPD %

(%) Limit

Pass/Fail

1,2,4,5-Tetrachlorobenzene*

67.1

 

 

9.11

 

 

1,2,4-Trichlorobenzene

62.1

44-142

Pass

4.96

50

Pass

1,2-Dichlorobenzene*

56.5

 

 

5.31

 

 

1,3,5,-Trinitrobenzene*

87.7

 

 

1.85

 

 

1,3-Dichlorobenzene*

51.1

 

 

5.58

 

 

1,3-Dinitrobenzene*

92.9

 

 

0.52

 

 

1,4-Dichlorobenzene*

53.1

 

 

5.14

 

 

1,4-Naphthoquinone*

82.5

 

 

4.89

 

 

1-Naphthylamine*

92.3

 

 

5.45

 

 

2,3,4,6-Tetrachlorophenol*

90.5

 

 

0.74

 

 

2,4,5-Trichlorophenol*

87.5

 

 

1.04

 

 

2,4-Dichlorophenol

89.0

39-135

Pass

0.47

50

Pass

2,4-Dimethylphenol

87.9

32-120

Pass

0.38

58

Pass

2,4-Dinitrophenol

87.5

D-191

Pass

7.00

132

Pass

2,4-Dinitrotoluene

92.9

39-139

Pass

1.44

42

Pass

2,6-Dichlorophenol*

87.8

 

 

1.90

 

 

2,6-Dinitrotoluene

93.6

50-158

Pass

3.18

48

Pass

2-Chloronaphthalene

75.9

60-120

Pass

7.87

24

Pass

2-Chlorophenol

81.7

23-134

Pass

3.08

61

Pass

2-Fluorobiphenyl*

86.9

 

 

3.43

 

 

2-Fluorophenol*

61.8

 

 

5.05

 

 

2-Methyl phenol*

84.8

 

 

0.68

 

 

2-Methylnaphthalene*

72.7

 

 

4.62

 

 

2-Naphthylamine*

113.0

 

 

2.93

 

 

2-Nitroaniline*

92.9

 

 

1.41

 

 

2-Nitrophenol

80.7

29-182

Pass

4.36

55

Pass

2-Picoline*

49.2

 

 

6.96

 

 

3,3'-Dichlorobenzidine

93.3

D-262

Pass

7.92

108

Pass

3,3'-Dimethylbenzidine*

99.3

 

 

0.90

 

 

3+4 Methyl phenol*

86.4

 

 

1.17

 

 

3-Methylcholanthrene*

87.9

 

 

8.34

 

 

3-Nitroaniline*

95.4

 

 

4.75

 

 

4 Aminobiphenyl*

114.6

 

 

2.36

 

 

2-methyl-4,6-Dinitrophenol

91.9

D-181

Pass

1.83

203

Pass

4-Bromophenyl phenyl ether

85.0

53-127

Pass

3.90

43

Pass

4-Chloro-3-methylphenol

91.1

22-147

Pass

3.06

73

Pass

4-Chloroaniline*

120.7

 

 

0.11

 

 

4-Chlorophenyl phenyl ether

82.3

25-158

Pass

4.57

61

Pass

4-Nitroaniline*

90.7

 

 

2.92

 

 

4-Nitrophenol

97.3

D-132

Pass

4.31

131

Pass

4-Nitroquinoline-1-oxide*

95.8

 

 

1.99

 

 

5-nitro-o-toluidine*

96.8

 

 

3.00

 

 

7,12-Dimethylbenz(a)-anthracene*

86.9

 

 

5.42

 

 

Acenaphthene

80.1

47-145

Pass

6.28

48

Pass

Acenaphthylene

81.3

33-145

Pass

4.75

74

Pass

Acetophenone*

80.2

 

 

5.11

 

 

Acetylaminofluorene*

94.7

 

 

6.09

 

 

Aniline*

84.0

 

 

7.85

 

 

Anthracene*

89.2

27-133

Pass

7.17

66

Pass

Azobenzene*

86.6

 

 

3.64

 

 

Benz(a)anthracene

89.2

33-143

Pass

8.15

53

Pass

Benzidine*

105.5

 

 

9.38

 

 

Benzo(a)pyrene

88.8

17-163

Pass

9.10

72

Pass

Benzo(b)fluoranthene

89.2

24-159

Pass

6.83

71

Pass

Benzo(ghi)perylene

90.1

D-219

Pass

11.44

97

Pass

Benzo(k)fluoranthene

89.2

11-162

Pass

7.01

63

Pass

Benzoic acid*

58.7

 

 

6.47

 

 

Benzyl alcohol*

81.3

 

 

2.07

 

 

Bis(2-chlorethoxy)methane

85.4

33-184

Pass

0.19

54

Pass

Bis(2-chloroethyl)ether

74.6

12-158

Pass

6.50

108

Pass

Bis(2chloroisopropyl)ether

73.7

36-166

Pass

8.23

76

Pass

Bis(2-ethylhexyl) phthalate

92.3

8-158

Pass

0.81

82

Pass

Analyte

Average MS, MSD Recovery %

Range P,Ps %

Pass/Fail

RPD %

(%) Limit

Pass/Fail

Benzyl butyl phthalate

91.7

D-152

Pass

1.99

60

Pass

Carbazole*

93.1

 

 

5.94

 

 

Chrysene

89.4

17-168

Pass

10.27

87

Pass

cis-Isosafrole*

79.9

 

 

3.64

 

 

Dibenz(ah)anthracene

91.2

D-227

Pass

6.46

126

Pass

Dibenzofuran*

82.7

 

 

6.37

 

 

Diethyl phthalate

94.3

D-120

Pass

1.07

100

Pass

Dimethyl phthalate

93.2

D-120

Pass

0.97

183

Pass

Dimethylaminoazobenzene*

93.4

 

 

4.06

 

 

Di-n-butyl phthalate

93.9

1-120

Pass

5.12

47

Pass

Di-n-octyl phthalate

90.7

4-146

Pass

2.69

69

Pass

Dinoseb*

91.0

 

 

1.83

 

 

Diphenylamine*

91.3

 

 

2.03

 

 

Ethylmethane Sulfonate*

79.1

 

 

3.34

 

 

Fluoranthene

91.6

26-137

Pass

6.57

66

Pass

Fluorene

85.1

59-121

Pass

5.18

38

Pass

Hexachlorobenzene

86.1

D-152

Pass

6.56

55

Pass

Hexachlorobutadiene

48.8

24-120

Pass

5.56

62

Pass

Hexachlorocyclopentadiene*

46.5

 

 

4.15

 

 

Hexachloropropene*

49.9

 

 

5.69

 

 

Indeno(1,2,3-cd)pyrene

89.6

D-171

Pass

11.95

99

Pass

Isophorone

85.0

21-196

Pass

0.36

93

Pass

Methapyrilene*

92.8

 

 

3.99

 

 

Methyl Methane Sulfonate*

53.4

 

 

8.39

 

 

Naphthalene

71.4

21-133

Pass

4.06

65

Pass

NDMA*

38.6

 

 

17.34

 

 

Nitrobenzene

77.4

35-180

Pass

5.18

62

Pass

Nitrobenzene-d5

82.0

 

 

5.54

 

 

N-Nitroso-diethylamine*

71.4

 

 

6.09

 

 

N-nitroso-di-n-butylamine*

88.2

 

 

0.45

 

 

N-nitroso-di-n-propylamine

83.6

D-230

Pass

3.64

87

Pass

N-Nitrosomethyl ethylamine

62.8

 

 

11.95

 

 

N-Nitroso-morpholine*

82.3

 

 

13.96

 

 

N-Nitroso-piperidine*

85.7

 

 

2.10

 

 

N-Nitroso-pyrrolidine*

85.7

 

 

0.86

 

 

o-toluidine*

100.1

 

 

1.58

 

 

Pentachlorobenzene*

78.8

 

 

7.32

 

 

Pentachloroethane*

55.3

 

 

7.13

 

 

Pentachloronitrobenzene*

89.1

 

 

5.28

 

 

Pentachlorophenol

93.5

14-176

Pass

3.03

86

Pass

Analyte

Average MS, MSD Recovery %

Range P,Ps %

Pass/Fail

RPD %

(%) Limit

Pass/Fail

Phenacetin*

92.7

 

 

3.73

 

 

Phenanthrene

88.8

54-120

Pass

6.07

39

Pass

Phenol

62.2

5-120

Pass

5.59

64

Pass

Phenol-d5

61.8

 

 

6.61

 

 

p-Terphenyl-d14*

89.1

 

 

6.72

 

 

Pyrene

90.8

52-120

Pass

7.51

49

Pass

Pyridine*

32.3

 

 

4.49

 

 

Safrole*

83.0

 

 

3.83

 

 

trans-Isosafrole*

82.8

 

 

1.56

 

 

 

The matrix spike (MS) and matrix spike duplicate (MSD) were successfully spiked and measured recoveries were within the range specified in Table 6 in Method 625.1. The relative percent difference (RPD) between the matrix spike and duplicate sample showed excellent agreement when compared to the limit allowed. The agreement was generally well below the limit, sometimes more than an order of magnitude better.

Conclusion


US EPA Method 625 is an important method for evaluation of water pollution or clean-up. It allows a full suite of analytes to be evaluated at one time using GC/MS. Sample preparation is an important part of the process and disk solid phase extraction can provide advantages in using less solvent, eliminating emulsions and providing good extraction across the suite of analytes considered while minimizing exposure. A number of analytes within Tables 1-3 were extracted simultaneously with a 1 litre sample volume. This was to challenge the extraction method and matrix components that may interfere with good adsorption and release of the analytes. The results show excellent performance of the One-Pass disk coupled with a Carbon Cartridge for capture of the analytes.

Reduced sample volumes can be used for this method to improve method performance as long as all Method Detection Limits (MDLs) and reporting limits are met. Solid phase extraction disks are another tool for the environmental laboratory to consider when evaluating their workflow for increased efficiency and safety. Other things can be considered once analytical performance is demonstrated, such as the ability to use less solvent, and reducing the need for evaporation and subsequent solvent recollection. Automation can also enhance reproducibility. Excellent duplicate agreement was shown here, even for the more difficult samples. Overall, the demonstrated analytical performance meets the criteria required and other favourable factors can be included in the decision making process to bring newer technology into today’s modern laboratory.

 

References

  1. Method Update Proposed Rule, Federal Register, February 19, 2015, page 8946.
  2. Method 625.1, December 14 revision, can be found in the MUR, February 20, 2014. 

Appendix 1


Table 6 from US EPA Method 625.1, December 2014

 

Literature number: AN123-HOR