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. Contact Customer Service 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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