New Custom UCMR4 Standard for EPA Method 530 on the Rxi-5Sil MS

We recently stocked custom EPA Method 530 standards made specifically for labs participating in Unregulated Contaminant Monitoring Rule 4 (UCMR4). Quantitative Certificates of Analysis with Data Packs are available for each item. Email csreps@restek.com or phone 800-356-1688 ext. 3 to place your order (items are not available at Restek.com).

EPA Method 530, the Determination of Select Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and Gas Chromatography / Mass Spectrometry was developed on the Rtx-1701, but section 6.12.1 of the method states that “any capillary column that provides adequate capacity, resolution, accuracy, and precision may be used.” 3 of the 4 Method 530 target analytes, butylated hydroxyanisole, o-toluidine, and quinoline have been included in UCMR4; the 4th target analyte, dimethipin, was included in UCMR4 as part of EPA 525.3. It isn’t really clear to me why a new method was made for these compounds instead of relying on EPA Method 525.3. Method 530 uses a 6mL divinyl benzene or polystyrene/divinyl benzene cartridge for extracting 1L where 525.3 has multiple cartridge and disk SPE options. The analysis is a couple minutes faster on the Rxi-5Sil MS under the 525.3 conditions. The selectivity of the two columns are similar, the primary difference being that butylated hydroxyanisole (BHA) is less retained relative to acenaphthene-D10 on the Rxi-5Sil MS. If your lab has limited resources, you should be able to perform both method 530 and 525.3 on one instrument set up for method 525.3.

Cat# 572262 – Method 530 UCMR4 Standard (in Methanol)

Contaminant CAS Registry Number Minimum Reporting Level Standard Concentration
butylated hydroxyanisole (BHA) 25013-16-5 0.03 µg/L 150 µg/mL
o-Toluidine 95-53-4 0.007 µg/L 35 µg/mL
Quinoline 91-22-5 0.02 µg/L 100 µg/mL

 

Cat# 572265 – Method 530 UCMR4 Surrogate Standard (in Methanol)

Contaminant CAS Registry Number Standard Concentration
Quinoline-D7 34071-94-8 500 µg/mL
o-Toluidine-D9 194423-47-7 500 µg/mL

 

Cat# 572266 – Method 530 UCMR4 Internal Standard (in Acetone)

Contaminant CAS Registry Number Standard Concentration
Acenaphthene-D10 15067-26-2 500 µg/mL
Phenanthrene-D10 1517-22-2 500 µg/mL

 

I’ve collected example chromatograms on the Rxi-5sil MS using the same GC conditions that were used for the EPA Method 525.3 UCMR4 standard (Section 10.2.3.1), but with a new SIM program generated using the AutoSIM feature of MSD Chemstation. This was mainly to demonstrate the the two methods can be run on the same GC-MS with the same analytical column.

 

SIM Analysis of EPA 530 UCMR4 Standard Run at Method Reporting Limit (MRL) on the Rxi-5Sil MS

SIM Analysis of EPA 530 UCMR4 Standard Run at 10x the Method Reporting Limit (MRL) on the Rxi-5Sil MS

 

Peaks tR (min) MRL Conc. (µg/mL) 10x MRL Conc. (µg/mL)
1. o-Toluidine-D9 (SUR) 5.64 1.0 1.0
2. o-Toluidine 5.70 0.070 0.070
3. Quinoline-D7 (SUR) 8.22 1.0 1.0
4. Quinoline 8.26 0.20 0.20
5. Butylated hydroxyanisole (BHA) 11.50 0.30 0.30
6. Acenaphthene-D10 (IS) 11.54 1.0 1.0
7. Phenanthrene-D10 (IS) 15.05 1.0 1.0

 

Column Rxi-5Sil MS, 30 m, 0.25 mm ID, 0.25 µm (cat.# 13623)
Sample Method 530 UCMR4 Standard (cat.# 572262)
Method 530 UCMR4 Surrogate Standard (cat.# 572265)
Method 530 UCMR4 Internal Standard (cat.# 572266)
Diluent: Dichloromethane
Injection
Inj. Vol.: 1 µL pulsed splitless (hold 1.0 min)
Liner: 4 mm Single Taper w/Wool (cat.# 23303)
Inj. Temp.: 275 °C
Pulse Pressure: 30 psi (206.8kPa)
Pulse Time: 1.05 min
Purge Flow: 60 mL/min
Oven
Oven Temp.: 70 °C (hold 1.5 min) to 200 °C at 10 °C/min (hold 0 min) to 320 °C at 7 °C/min (hold 3 min)
Carrier Gas He, constant flow
Flow Rate: 1.2 mL/min
Detector MS
Mode: SIM
SIM Program:
Group Start Time (min) Ion(s) (m/z) Dwell (ms)
1 1.543 106, 107, 112, 114 25
2 6.917 102, 108, 129, 136 25
3 9.881 137, 162, 164, 180 25
4 13.297 160, 188 25
Transfer Line Temp.: 280 °C
Analyzer Type: Quadrupole
Source Type: Stainless Steel
Drawout Plate: 6 mm ID
Source Temp.: 280 °C
Quad Temp.: 180 °C
Solvent Delay Time: 1.45 min
Tune Type: DFTPP
Ionization Mode: EI
Instrument HP6890 GC & 5973 MSD

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