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See Semivolatiles Clearly with Rugged, Reliable Rxi-SVOCms Columns

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  • Outstanding inertness keeps calibrations passing and samples running.
  • Excellent resolution of critical pairs for improved accuracy.
  • Consistent column-to-column performance.
  • Long column lifetime.
Our Rxi-SVOCms column was named Best New Separations Product of the Year in the SelectScience Scientists' Choice Awards
 

Designed specifically for semivolatiles analysis, Restek’s new Rxi-SVOCms columns ensure consistent performance that will keep calibrations passing longer, so you can run more samples before needing to recalibrate the instrument or replace the column. Our new polymer and deactivation chemistries produce highly inert columns with tightly controlled selectivity resulting in exceptional performance for a wide range of analytes (acidic, basic, and neutral).

Rxi-SVOCms columns are tuned specifically to improve peak shape for challenging SVOCs, such as pentachlorophenol, pyridine, and benzidine, as well as to ensure optimized resolution of difficult polycyclic aromatic hydrocarbons (PAH). As shown in Figure 1, the most problematic reactive analytes show highly symmetrical peak shapes and good responses. In addition, excellent resolution (≥85% valley) is obtained for benzo[b]fluoranthene and benzo[k]fluoranthene, which are isobaric PAHs that must be separated chromatographically, as well as for indeno[1,2,3-cd]pyrene and dibenz[a,h]anthracene.

For chemists in the environmental industry who are slowed down by variable column performance, frequent calibration failures, and poor column lifetimes, switching to rugged Rxi-SVOCms columns can ensure data requirements are met longer and downtime is minimized.

Figure 1: Rxi-SVOCms columns provide outstanding chromatographic performance, reliably producing good peak shape and resolution even for problematic compounds. Split injection is recommended, when possible, because is minimizes the effect of inlet contamination on transfer of sample to the analytical column.

 

Stable Calibrations Increase Sample Throughput

Failed calibrations mean lost productivity as sample analysis must be put on hold for time-consuming maintenance and recalibration. The improved inertness of Rxi-SVOCms columns overcomes this, resulting in an average response factor %RSD from the initial calibration of six columns of just 6% over all compounds and columns (Table I). Extremely low and consistent response factors ensure that calibrations will last longer, allowing more samples to be run before recalibration is required. As shown in Figure 2, consistent peak shapes and retention times are seen even across different concentrations of pyridine and pentachlorophenol, which are problematic compounds that tend to tail and often fail calibration criteria on columns that are not highly inert.

Table I: Stable performance means fewer recalibrations and more time available for running samples, which improves lab productivity. Green indicates passing initial calibrations (n = 6 columns).

Compound

Calibration Range (µg/mL)

Average %RSD of Response Factors

N-Nitrosodimethylamine

1 - 120

4.70%

Pyridine

1 - 120

6.10%

(SS) 2-Fluorophenol

1 - 120

1.70%

(SS) Phenol-d6

1 - 120

2.10%

Phenol

1 - 120

3.20%

Aniline

1 - 120

3.10%

Bis(2-chloroethyl)ether

1 - 120

2.40%

2-chlorophenol

1 - 120

2.80%

1,3-dichlorobenzene

1 - 120

2.60%

1,4-Dichlorobenzene

1 - 120

2.10%

Benzyl alcohol

1 - 120

3.30%

1,2-Dichlorobenzene

1 - 120

2.70%

2-Methylphenol

1 - 120

3.30%

Bis(2-chloroisopropyl)ether

1 - 120

2.40%

4-Methylphenol/3-methylphenol

1 - 120

3.30%

N-nitroso-di-n-propylamine

1 - 120

3.80%

Hexachloroethane

1 - 120

3.00%

(SS) Nitrobenzene-D5

1 - 120

1.60%

Nitrobenzene

1 - 120

2.60%

Isophorone

1 - 120

3.40%

2-Nitrophenol

1 - 120

7.00%

2,4-Dimethylphenol

1 - 120

3.70%

Benzoic acid

2.5 - 120

25.00%

Bis(2-chloroethoxy)methane

1 - 120

3.60%

2,4-Dichlorophenol

1 - 120

4.10%

1,2,4-Trichlorobenzene

1 - 120

2.80%

Naphthalene

1 - 120

3.20%

4-Chloroaniline

1 - 120

3.90%

Hexachlorobutadiene

1 - 120

3.70%

4-Chloro-3-methylphenol

1 - 120

4.40%

2-Methylnaphthalene

1 - 120

3.40%

1-Methylnaphthalene

1 - 120

3.60%

Hexachlorocyclopentadiene

1 - 120

6.90%

2,4,6-Trichlorophenol

1 - 120

5.90%

2,4,5-Trichlorophenol

1 - 120

6.20%

(SS) 2-Fluorobiphenyl

1 - 120

1.10%

2-Chloronaphthalene

1 - 120

2.80%

2-Nitroaniline

1 - 120

7.80%

1,4-Dinitrobenzene

1 - 120

11.10%

Dimethyl phthalate

1 - 120

3.40%

1,3-Dinitrobenzene

1 - 120

10.80%

2,6-Dinitrotoluene

1 - 120

7.80%

Acenaphthylene

1 - 120

4.10%

1,2-Dinitrobenzene

1 - 120

8.10%

3-Nitroaniline

1 - 120

5.80%

Acenaphthene

1 - 120

3.30%

2,4-Dinitrophenol

2.5 - 120

17.30%

4-Nitrophenol

1 - 120

7.90%

Dibenzofuran

1 - 120

3.50%

2,4-Dinitrotoluene

1 - 120

11.60%

2,3,5,6-Tetrachlorophenol

1 - 120

10.40%

2,3,4,6-Tetrachlorophenol

1 - 120

7.30%

Diethyl phthalate

1 - 120

4.50%

4-Chlorophenyl phenyl ether

1 - 120

3.60%

Fluorene

1 - 120

4.40%

4-Nitroaniline

1 - 120

9.10%

4,6-Dinitro-2-methylphenol

2.5 - 120

15.10%

N-nitrosodiphenylamine

1 - 120

4.60%

Diphenylhydrazine

1 - 120

4.60%

(SS) 2,4,6-Tribromophenol

1 - 120

5.50%

4-Bromophenyl phenyl ether

1 - 120

5.50%

Hexachlorobenzene

1 - 120

4.30%

Pentachlorophenol

1 - 120

10.60%

Phenanthrene

1 - 120

3.70%

Anthracene

1 - 120

4.80%

Carbazole

1 - 120

5.30%

di-n-Butyl phthalate

1 - 120

7.90%

Fluoranthene

1 - 120

5.10%

Benzidine

1 - 120

9.30%

(SS) Pyrene-D10

1 - 120

1.50%

Pyrene

1 - 120

4.30%

(SS) p-Terphenyl-d14

1 - 120

1.80%

3,3'-Dimethylbenzidine

1 - 120

9.50%

Butyl benzyl phthalate

1 - 120

8.60%

Bis(2-ethylhexyl)adipate

1 - 120

10.50%

3,3'-Dichlorobenzidine

1 - 120

8.50%

Benz[a]anthracene

1 - 120

3.20%

Chrysene

1 - 120

3.70%

Bis(2-ethylhexyl)phthalate

1 - 120

10.40%

Di-n-octyl phthalate

1 - 120

13.20%

Benzo[b]fluoranthene

1 - 120

5.60%

Benzo[k]fluoranthene

1 - 120

4.90%

Benzo[a]pyrene

1 - 120

6.30%

Indeno[123-cd]pyrene

1 - 120

7.20%

Dibenz[a,h]anthracene

1 - 120

7.50%

Benzo[ghi]perylene

1 - 120

6.40%

 

Average %RSD:

6.00%

 

Figure 2: Highly inert Rxi-SVOCms columns produce excellent peak shapes and consistent retention times, even for low levels of failure-prone reactive compounds, such as pyridine (basic amine) and pentachlorophenol (acidic phenol).

 

Restore Performance Easily with Rugged, Long Life Rxi-SVOCms Columns

Accumulation of components from highly complex environmental samples is a routine challenge, but it doesn’t have to be a column killer. Improved column chemistry ensures that Rxi-SVOCms column performance is durable even under very aggressive conditions. In Figure 3, we subjected columns to repeated injections of a dirty sample, monitored calibration performance, and cut off contaminated sections after every 30 sample injections. Even after 300 injections, performance was easily restored with a quick column trim as evidenced by fewer than 10% of compounds failing the post-trim calibration check. Bringing back performance with simple routine maintenance means more samples can be analyzed with less downtime and fewer column replacements.

Figure 3: Column performance is completely restored by trimming following repeated exposure to a highly complex sample. Rugged Rxi-SVOCms columns come back to life so you can keep running samples instead of changing columns and recalibrating.

300-Sample Ruggedness Test Experimental Design

Each day, 30 injections of a diesel particulate extract (NIST SRM 1975) were made, and a continuing calibration verification (CCV) standard was run after every 10 sample injections. After the 3rd daily CCV, the column was trimmed, and the liner, septum, and inlet seal were replaced. This sequence was repeated for 10 days, and the entire experiment was repeated on a second column. 

  • The blue line includes all CCV injections and demonstrates that performance was first lost, as expected due to contamination from the sample matrix, and then fully restored following maintenance.
  • The green line plots only post-maintenance CCV injections and demonstrates calibration performance stability.

figure-article-EVSS3820-03.jpg

Consistent Performance Is Built into Every Column

From our proprietary polymer chemistry to the final QC test, every aspect of manufacturing Rxi-SVOCms columns is tightly controlled and stringently tested. The result is extremely consistent column-to-column performance, so you get the same chromatography from every column you install. Stable retention times, even for 2,4-dinitrophenol, which is an active and often problematic compound, and extremely low-bleed profiles characterize Rxi-SVOCms columns (Figure 4).

Figure 4: Every Rxi-SVOCms column provides consistent retention times and a low-bleed profile, resulting in dependable chromatographic performance from every column you receive.

 

Reliably Resolve Challenging Environmental PAH Compounds

Polycyclic aromatic hydrocarbons (PAH) are some of the most difficult compounds to separate in semivolatiles methods. Reporting accurate results at trace-levels requires a highly selective and efficient column that can reliably separate closely eluting compounds. Figure 5 demonstrates that the Rxi-SVOCms column provides optimized resolution of 23 priority pollutants, including benzo[b]fluoranthene and benzo[k]fluoranthene which must be separated chromatographically in order to be reported individually.

Figure 5: Rxi-SVOCms columns provide optimized separation of closely eluting priority PAH pollutants, including critical isobars that cannot be distinguished by MS alone.

 
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