2017 EPA Method Update Rule and EPA Method 624

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2017 EPA Method Update Rule and EPA Method 624

Transcript Of 2017 EPA Method Update Rule and EPA Method 624

Application Note
OI Analytical, a Xylem brand • 4412-01
2017 EPA Method Update Rule and EPA Method 624.1
PETROCHEMICAL SERIES
Introduction
Method 624 is for the determination of volatile organic compounds in industrial discharges and other liquid environmental samples by gas chromatography combined with mass spectrometry (GC/MS). The method was developed and validated through inter-laboratory studies more than 29 years ago. The purge and trap parameters were restricted to purging the sample at ambient temperature at 40ml/minute for 11 minutes and desorbing for 4 minutes. The method also has a relatively limited analyte list. Method 624.1 is a performance-based method. New technology such as capillary columns, better purge and traps, optimized instrument parameters, and more sensitive GC/MS instruments will enable laboratories to achieve better precision and % Relative Standard Deviation (%RSD) for calibrations than the prescribed 35% in Method 624 and 624.1. Allowing such high RSD values on most compounds is often an indicator that the analytical system is out of control and associated data may be suspect. The analyte list for 624.1 has been expanded and includes many compounds that can also be run by 8260.

Internal Standards and Surrogate Standards can now be varied by compound and concentration to match 8260. Also since laboratories are permitted to use more stringent acceptance criteria than the method prescribes, it may be possible to analyze samples for Method 624.1 and 8260 at the same time. Method 624.1 requires running a matrix spike and matrix spike duplicate on 5% of samples from every site or each discharge type sample, which can be a hardship on the lab. It also provides improvement in the procedure for Method Detection Limit (MDL) studies using 40 CFR Part 136 which many labs are already implementing for Method 8260.
The purpose of this paper is to use Method criteria from 624.1 and 8260 in a way that will most effectively and efficiently allow labs to run 624 and 8260 in the same batch.
Experimental
The instrumentation used for sample concentration was an OI Analytical 4760 Purge and Trap with a #10 trap which contains Tenax, silica gel and carbonized molecular sieve along with a 4100 Sample Processor. An Agilent 7890A/5975C GC/MS was used for chromatographic separation and detection. Please see Table 1 for instrument parameters.
50 ng of Bromofluorobenzene(BFB) was injected on all days that the instrument was run for this study. An eight-point calibration was analyzed, which included all compounds listed as Priority Pollutants in Method 624.1 Table 1, additional purgeables from Method 624.1 Table2, and many compounds from the Method 8260 scope of work. The list chosen was based on compounds which are representative of volatiles analysis by 8260, availability of standards, and appropriateness of the method. Purge and trap may be a difficult or inappropriate technique for several compounds listed in both methods. The calibration range for most compounds was 2ppb to 200ppb with higher concentrations run for the poor performers such as ketones, alcohols, nitriles, and 1,4-Dioxane. Internal Standards and Surrogates were chosen based upon what is readily available in commercial mixes for 8260. An initial demonstration of capability (IDOC) was run at 50ppb for most compounds with the aforementioned compounds at higher concentrations. A method detection limit study was performed over a three day period at varying concentrations.

Figure 1. 4100, 4760, and GC/MS

Table 1. Instrument Parameters

Purge-and-Trap Trap Purge Gas Purge Time Sparge Mount Temperature Sample Temperature (purge) Sample Temperature (bake) Desorb Time

Eclipse 4760 P&T Sample Concentrator #10 trap; Tenax® / Silica gel / CMS Zero grade Helium at 40 mL/min 11 min 45 ˚C 45 ˚C 55 ˚C 0.5 min

Bake Time

3 min

OI #10 Trap Temperature
Water Management
Transfer Line Temperature Six-port Valve Temperature Gas Chromatograph Column Carrier Gas Inlet Temperature Inlet Liner Column Flow Rate Split Ratio
Oven Program
Mass Spectrometer Mode Scans/Second Solvent Delay Transfer Line Temperature Source Temperature Quadrupole Temperature Draw Out Plate

Ambient during purge 180 ˚C during desorb pre-heat 190 ˚C during desorb 210 ˚C during bake 120 ˚C during purge Ambient during desorb 240 ˚C during bake 140 ˚C
140 ˚C
Agilent 7890A Restek Rtx – VMS 30 meter, 0.25 mm ID, 1.4 µm Zero grade helium
240 ˚C
Agilent Ultra Inert, 1 mm straight taper
0.8 mL/min
125:1 Hold at 40 ˚C for 2 min 16 ˚C/minute to 180 ˚C 40 ˚C/minute to 220 ˚C Hold at 220 ˚C for 2.5 min Total GC Run is 14.25 min Agilent 5975C
Scan 35-300 amu
5.19
1.60 min
250 ˚C
300 ˚C
200 ˚C
6 mm

2

Results
BFB criteria listed in Table 4 of Method 624.1, Table 4 of 8260B, and Table 3 of 8260C were met each day the instrument was run. The calibration easily met the 624.1 RSD criteria of 35%. The calibration met the 15% RSD criteria for Method 8260B, and the System Performance Check Compound (SPCC) criteria and Calibration Check Compound (CCC) criteria. Method 8260C requires a 20% RSD, so if Method 8260B criteria are met, all three methods could be used to report data. Laboratories will need to check with reporting authorities for this allowance. Each calibration point was re-quantitated using the average response factor and also linear regression weighted with the inverse of concentration (1/C). This provided readback for each calibration level, ensuring that all levels had a good calculated recovery. The results for this re-quantitation were evaluated using % Relative Standard Deviation (%RSD) as well as % Relative Standard Error (%RSE). The RSE indicates if any point has a high deviation from the curve. The %RSD and %RSE were very similar for quantitation using average response and linear. Since the %RSD criteria was met for both Method 624.1 and 8260B/C, the IDOCs and MDLs were processed using average response. The DOC recovery and RPD limits for compounds listed in Table 6 of Method 624.1 were met. Interim criteria of 60-140% recovery and 30% RPD were easily met for the remainder of the compounds. The MDL’s met 40 CFR Part 136 rules for acceptance. The MDL spike level was greater than the calculated MDL, and the ratio of the spiked amount to calculated MDL was less than 10. Please see table 2 for results. Figure 2. 50ppb Calibration Standard
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Compound
Pentafluorobenzene (IS) Dichlorodifluoromethane *Chloromethane(S) *Vinyl chloride(C) *Bromomethane *Chloroethane Trichlorofluoromethane Ethyl ether Ethanol *1,1-Dichloroethene(C) Carbon disulfide 1,1,2-Trichloro-1,2,2-trifluoroethane Methyl iodide *Acrolein Allyl chloride Isopropanol *Methylene chloride Acetone *trans-1,2-Dicholroethene Methyl tert-butyl ether 2-Methyl-2-propanol Acetonitrile Chloroprene Diisopropyl ether *1,1-Dichloroethane(S) *Acrylonitrile Vinyl acetate Ethyl-tert-butyl ether cis-1,2-Dichloroethene 2,2-Dichloropropane Bromochloromethane *Chloroform(C) Methyl acrylate *Carbon tetrachloride Tetrahydrofuran Dibromofluoromethane (SS) *1,1,1-Trichloroethane 2-Butanone 1,1-Dichloropropene 1,4-Difluorobenzene (IS) *Benzene Propionitrile Methacrylonitrile tert-Amyl methyl ether 1,2-Dichloroethane-d4 (SS) Isobutanol *1,2-Dichloroethane *Trichloroethene tert-Amyl ethyl ether Dibromomethane *1,2-Dichloropropane(C) *Bromodichloromethane Methyl methacrylate 1,4-Dioxane *2-Chloroethyl-vinyl-ether *cis-1,3-Dichloropropene Chlorobenzene-d5 (IS)

Quant RL Ion (ppb)

168

N/A

85

2

50

2

62

2

94

2

64

2

101

2

74

2

45

100

96

2

76

2

101

2

142

2

56

4

76

2

45

20

84

2

58

10

96

2

73

2

59

10

41

20

53

2

45

2

63

2

53

2

43

2

59

2

96

2

77

2

128

2

83

2

55

2

117

2

42

2

113

N/A

97

2

72

10

75

2

114

N/A

78

2

54

2

41

2

73

2

102

N/A

43

20

62

2

130

2

59

2

93

2

63

2

83

2

69

2

88

50

63

2

75

2

117

N/A

Avg

% RSE %RSE

RF % RSD (Avg

(Linear

RF Calc.) 1/C Calc.)

N/A 0.18 0.54 0.42 0.23 0.23 0.54 0.21 0.01 0.34 0.94 0.36 0.64 0.10 0.21 0.07 0.37 0.08 0.48 1.99 0.11 0.07 1.14 2.07 1.07 0.33 1.96 1.72 0.51 0.40 0.28 0.84 1.02 0.71 0.35 0.46 0.69 0.08 0.62 N/A 1.24 0.22 0.58 0.69 0.05 0.04 0.61 0.40 0.96 0.27 0.49 0.48 0.30 0.003 0.35 0.54 N/A

N/A 4.08 7.01 7.48 6.06 3.63 4.82 4.14 6.75 5.63 5.35 3.56 3.30 5.10 1.90 9.21 3.98 5.34 9.05 4.66 5.59 4.27 3.50 5.00 1.97 5.72 5.73 2.76 2.19 9.19 3.53 1.86 5.90 3.64 4.15 1.08 3.41 6.01 1.98 N/A 2.09 6.89 6.08 4.29 1.67 4.39 2.46 3.05 2.91 2.77 2.47 3.23 4.97 9.28 5.83 1.83 N/A

N/A 4.07 7.01 7.48 6.06 3.63 4.81 4.19 10.3 5.66 5.34 3.55 3.32 5.11 1.94 9.20 4.01 5.33 9.12 4.60 5.59 4.26 3.54 4.95 1.98 5.69 5.66 2.77 2.21 9.17 3.46 1.89 5.90 3.66 4.38 1.09 3.41 6.01 1.97 N/A 2.10 6.88 6.14 4.23 1.67 5.06 2.47 3.09 2.89 2.78 2.46 3.22 4.97 4.42 5.85 1.80 N/A

N/A 5.59 11.0 10.7 8.01 2.95 7.91 4.44 3.17 5.27 5.90 4.96 4.00 3.57 1.24 10.1 6.09 7.90 2.38 1.45 5.54 3.02 2.28 3.81 1.92 5.25 1.93 2.70 2.56 12.9 3.56 2.65 5.13 5.45 2.86 1.17 5.59 5.52 2.36 N/A 3.46 3.59 3.60 5.26 1.81 4.36 4.28 4.30 1.37 4.88 3.40 5.41 4.37 4.03 3.23 2.60 N/A

MDL (ppb)

IDOC Precision (% RPD)

IDOC Accuracy (% REC)

N/A 0.28 0.17 0.17 0.35 0.28 0.30 0.37 26.3 0.22 0.36 0.22 0.13 0.75 0.27 7.15 0.16 2.10 0.43 0.08 3.98 1.27 0.11 0.06 0.14 0.26 0.24 0.12 0.20 0.34 0.15 0.16 0.13 0.14 0.35 N/A 0.13 1.99 0.20 N/A 0.08 1.28 0.41 0.22 N/A 3.10 0.14 0.16 0.09 0.12 0.19 0.07 0.12 10.7 0.18 0.10 N/A

N/A 4.97 1.29 1.08 8.22 1.29 1.62 1.41 19.8 1.18 1.32 1.86 0.84 4.95 1.94 19.8 1.06 8.85 1.26 1.27 13.8 13.9 1.43 1.15 1.34 7.00 1.68 1.04 1.23 1.49 0.94 1.29 2.05 2.43 3.67 1.58 0.48 3.98 1.36 N/A 1.33 9.00 1.85 1.65 2.11 7.25 1.43 1.00 0.67 2.13 0.66 0.99 5.17 21.1 0.91 0.90 N/A

N/A 96.1 101 99.9 103 99.6 101 106 90.0 99.1 102 101 101 107 102 99.0 103 105 97.3 105 106 106 104 103 103 112 106 103 102 102 104 104 107 102 108 101 102 106 104 N/A 103 99.5 106 101 103 99.8 104 102 101 105 102 104 108 96.0 105 104 N/A

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Compound

Quant RL

Avg

% RSE %RSE

Ion (ppb)

RF % RSD (Avg

(Linear

RF Calc.) 1/C Calc.)

Toluene-d8(SS) *Toluene(C) 2-Nitropropane 4-Methyl-2-pentanone *Tetrachloroethene *trans-1,3-Dichloropropene Ethyl methacrylate *1,1,2-Trichloroethane *Chlorodibromomethane 1,3-Dichloropropane 1,2-Dibromoethane 2-Hexanone *Chlorobenzene(S) *Ethylbenzene(C) 1,1,1,2-Tetrachloroethane m,p-Xylenes o-Xylene Styrene *Bromoform(S) Isopropylbenzene cis-1,4-Dichloro-2-butene 1,4-Dichlorobenzene-d4 (IS) 4-Bromofluorobenzene (SS) n-Propylbenzene Bromobenzene *1,1,2,2-Tetrachloroethane(S) 2-Chlorotoluene 1,3,5-Trimethylbenzene 1,2,3-Trichloropropane trans-1,4-Dichloro-2-butene 4-Chlorotoluene tert-Butylbenzene 1,2,4-Trimethylbenzene sec-Butylbenzene p-Isopropytoluene *1,3-Dichlorobenzene *1,4-Dichlorobenzene n-Butylbenzene *1,2-Dichlorobenzene 1,2-Dibromo-3-chloropropane Hexachlorobutadiene 1,2,4-Trichlorobenzene Naphthalene 1,2,3-Trichlorobenzene

98

N/A

1.27

0.77

92

2

0.96

1.87

43

2

0.29

1.97

100

10

0.06

5.93

164

2

0.38

2.58

75

2

0.60

3.00

69

2

0.49

7.38

83

2

0.36

2.19

129

2

0.56

1.91

76

2

0.56

2.05

107

2

0.48

3.00

43

10

0.72

8.40

112

2

1.18

2.31

91

2

1.82

1.77

131

2

0.39

2.43

106

4

0.69

2.98

106

2

0.63

1.90

104

2

1.10

4.01

173

2

0.43

2.14

105

2

1.62

2.80

75

2

0.21

4.99

152

N/A

N/A

N/A

95

N/A

0.94

1.35

91

2

4.43

3.79

156

2

1.14

3.21

83

2

1.28

3.34

91

2

2.85

2.41

105

2

2.96

3.75

75

2

1.51

2.65

53

2

0.68

2.62

91

2

2.65

2.69

119

2

2.42

3.00

105

2

2.98

3.88

105

2

3.71

2.94

119

2

3.04

3.92

146

2

1.92

2.89

146

2

1.92

2.21

91

2

2.91

3.10

146

2

1.77

2.00

75

2

0.26

4.72

225

2

0.55

3.61

180

2

1.04

3.56

128

2

3.26

5.18

180

2

1.00

4.07

0.76 1.89 1.97 5.92 2.59 3.01 7.33 2.16 1.91 2.08 3.00 8.40 2.31 1.77 2.44 2.98 1.89 3.98 2.13 2.78 4.98 N/A 1.36 3.84 3.23 3.33 2.41 3.73 2.80 2.62 2.67 2.95 3.88 3.00 3.87 2.90 2.20 3.14 2.00 4.75 3.60 3.57 5.14 4.08

0.83 2.04 2.16 2.08 4.60 2.78 5.15 2.83 2.73 2.38 4.26 5.88 4.04 2.55 4.09 2.03 2.04 1.63 3.14 3.00 4.67 N/A 1.46 3.19 3.92 4.61 3.10 2.88 2.68 2.87 2.87 3.03 2.83 3.40 2.25 4.54 3.58 2.20 3.42 4.84 3.51 3.82 4.24 5.49

*Priority Pollutant (40 CFR 423, Appendix A)

IS - Internal Standard

SS – Surrogate Standard

S – 8260B System Performance Check Compound (SPCC)

C – 8260B Calibration Check Compound (CCC)

MDL (ppb)
N/A 0.12 0.28 0.87 0.13 0.10 0.16 0.19 0.07 0.08 0.09 0.30 0.08 0.12 0.17 0.13 0.11 0.17 0.19 0.08 0.20 N/A N/A 0.06 0.12 0.16 0.06 0.09 0.27 0.21 0.12 0.10 0.08 0.09 0.10 0.14 0.12 0.06 0.11 0.56 0.17 0.13 0.16 0.14

IDOC Precision (% RPD)
0.66 1.02 2.65 1.37 0.89 1.17 1.47 0.96 1.45 0.87 1.28 1.63 0.94 0.80 1.32 0.58 0.31 0.85 1.19 0.89 1.75 N/A 1.05 1.45 1.34 1.39 0.91 0.86 1.72 1.07 1.08 0.97 1.37 1.48 1.27 1.08 0.77 1.12 1.29 4.26 1.50 1.23 2.40 1.75

IDOC Accuracy (% REC)
99.9 102 102 104 102 104 106 102 103 103 102 107 103 103 102 105 103 105 103 104 104 N/A 99.7 104 102 101 103 103 103 103 103 101 104 102 103 100 101 102 99.6 97.7 97.6 98.7 99.7 99.0

5

Conclusions
Method performance is significantly improved with the allowance of better purge and trap parameters, such as the 0.5 minute desorb and heating sample during purge, as well as significant instrument improvements which have been made over the past 29 years. For these reasons method performance is better than Method 624.1 requires which may allow the laboratory to combine QC criteria with Method 8260 thus increasing sample capacity and productivity in the lab.
References
1. USEPA Method 624.1: Purgeables by GC/MS, December 2014.
2. USEPA EPA Method 8260B: Volatile Organic Compounds by Gas Chromatography/Mass Spectrometry (GC/MS), Revision 2, December 1996.
3. USEPA EPA Method 8260C: Volatile Organic Compounds by Gas Chromatography/Mass Spectrometry (GC/MS), Revision 3, August 2006.
4. USEPA 40 CFR Part 136, Appendix B. Definition and Procedure for the Determination of the Method Detection Limit.
5. Parr, Jerry L. 2017. Proposed Changes to the Clean Water Act, Methods 608, 624, and 625. Catalyst Information Resources Presentation.
6. Parr, Jerry L. 2017. 2016 Chemistry Standard. Volume 1, Module 4. NELAC Institute Presentation.
7. Burrows, Richard. 2017. Why We Need a Standard on Calibration. NELAC Institute Environmental Measurement Methods Expert Committee Presentation.
Acknowledgements
Thank you to Dr. Garrett Slaton at OI Analytical for his work on the Excel spreadsheet for %RSE.
Thank you to Mr. Jerry L. Parr and Dr. Richard Burrows at the NELAC Institute for their helpful advice regarding the method.

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