Several different volatile and semi-volatile contaminants find their way into water sources and terrestrial bodies around the world.
In the United States, stipulated US-EPA methods are followed to analyze such contaminants. In the European Union, the European Water Framework Directive is followed to test a huge number of the same compounds.
While such analytes are tackled differently from a regulatory point of view, it is evident that background monitoring takes place on a global basis.
The initial extraction of such analytes relies on the matrix being examined and is usually a multifaceted process; however, analysts are eventually presented with a certain form of extraction or organic solvent they must focus on to attain instrumental limits of quantification. This article presents the outcomes of such an evaporative procedure using the latest Biotage TurboVap® II.
The latest TurboVap® II is based on the strong foundations of performance and reliability that made it the frontrunner in the market for solvent evaporation.
The contemporary design integrates several latest customer-driven aspects to enable expanded functionality and easier use. Despite this fact, the TurboVap® II continues to utilize extremely efficient patented gas vortex shearing technology, which is synonymous with the brand of TurboVap®.
This advanced design includes several new improvements, such as enhanced sensors with automatic end-point detection, a well-lit glass tank for relatively greater visibility of the samples, an easy-access drain port, user-replaceable nozzles, and a menu-driven, color touchscreen for effortless monitoring and operation. The system can be placed in the fume hood or vented from the bench. Moreover, less space is needed because the footprint is evidently smaller in this contemporary unit.
Image Credit: Biotage
Experiment
A TurboVap® II evaporation system (P/N 415001) was used with the help of a TurboVap II® Rack with End-Point Sensors 6 Positions, 200 mL tubes (P/N 415100) utilizing 1 mL end-point evaporation tubes (P/N C128506).
Dichloromethane (DCM), p-Terphenyl, and a mixed analyte standard P/N 506559 were all bought from Sigma-Aldrich.
To obtain a concentration of ~111 ng/mL, 180 mL of DCM was introduced to six 200 mL, 1 mL end-point evaporation tubes and then spiked with 20 µg of each analyte. At first, the system was operated using the parameters recorded in Table 1.
Table 1. Source: Biotage
| Parameter |
Setting |
| Inlet pressure |
6 bar |
| Operating flow rate |
2.8 L/min |
| Water bath temperature |
40 °C |
Once the end-point sensors had identified the cut off volume (~ 0.7 mL) reached by the solvent, evaporation was automatically stopped. Following this, p-Terphenyl was added at a concentration of 20 µg/mL to all the six tubes, to serve as an external standard and allow the generation of the response factor (Response Factor).
A pipette was used to transfer the concentrated extract to a screw-capped autosampler vial and the internal walls of the evaporator tube were washed with DCM to ensure a final volume of 1 mL. The experimental process was repeated again but instead of a constant 2.8 L/minute gas flow, a ramped gradient flow was used as shown in Table 2.
Table 2. Source: Biotage
| Parameter |
Setting |
| Inlet pressure |
6 bar |
| Initial flow rate |
2.8 L/min hold for 4 minutes |
| Final flow rate |
7.0 L/min over 30 minutes |
| Water bath temperature |
40 °C |
Analysis
Using gas chromatography-mass spectrometry (GC-MS), each analyte was quantitatively determined after evaporation. GC separation method was performed on an Agilent 7890A fitted with QuickSwap.
The isolation of target analytes was done with the help of an Agilent J&W DB-5ms, 30 m x 0.25 mm ID x 0.25 μm column. Oven parameters were as follows: initial temperatures of 40 °C with a 2 minute isocratic hold; ramp conditions were 20 °C/minute to 290 °C and a hold for 1.5 minutes, and this was followed by a second ramp 100 °C/minute to 325 °C held for 4.6 minutes, offering a total run time of 20.95 minutes. Post run, the column was back flushed for a period of 2.4 minutes (about three void volumes).
The injection volume was configured at 2 µL, whereas helium was used as the carrier gas at a flow rate of 1 mL/minute (constant flow). The inlet was configured to work in splitless mode and the temperature of the inlet was maintained at 300 °C with a purge flow of 50 mL/minute at 0.8 minutes.
The GC system was directly linked to an Agilent 5975C mass spectrometer, with the transfer line temperature configured at 300 °C. The MS was used in electron impact ionization (EI), obtaining data in full scan mode between 40 and 285 m/z. Quadrupole and source temperatures were respectively maintained at 150 °C and 230 °C, while a solvent delay of 4 minutes was also maintained.
Table 3. Results of the evaporation and instrumental analysis. Source: Biotage
| Analyte |
%
Recovery
Fixed
Flow |
%
RSD
Fixed
Flow |
%
Recovery
Ramped
Flow |
%
RSD
Ramped
Flow |
| n-Nitrosodimethylamine |
90.8 |
5.0 |
89.8 |
2.2 |
| Phenol |
83.3 |
4.5 |
86.5 |
2.7 |
| Bis(2-Chloroethyl) ether |
80.2 |
5.6 |
82.7 |
2.3 |
| 2-Chlorophenol |
80.8 |
4.7 |
83.1 |
2.1 |
| 1,3-Dichlorobenzene |
78.6 |
5.2 |
79.5 |
1.9 |
| 1,4-Dichlorobenzene |
78.6 |
5.3 |
80.3 |
1.6 |
| 1,2-Dichlorobenzene |
79.8 |
5.2 |
81.6 |
1.5 |
| Bis(2-Chloroisopropyl) ether |
81.9 |
4.7 |
85.4 |
1.5 |
| n-Nitrosodi-n-propylamine |
99.2 |
2.9 |
101.2 |
2.1 |
| Hexachloroethane |
80.0 |
3.8 |
80.5 |
2.6 |
| Nitrobenzene |
85.3 |
4.7 |
88.9 |
2.7 |
| Isophorone |
88.2 |
4.9 |
95.1 |
2.2 |
| 2-Nitrophenol |
84.3 |
3.3 |
86.9 |
2.0 |
| 2,4-Dimethylphenol |
85.1 |
5.0 |
88.6 |
4.2 |
| Bis(2-Chlorethoxy) methane |
84.5 |
4.9 |
90.0 |
2.3 |
| 2,4-Dichlorophenol |
83.7 |
4.2 |
89.8 |
3.7 |
| 1,2,4-Trichlorobenzene |
80.0 |
5.1 |
84.0 |
2.7 |
| Naphthalene |
81.2 |
4.9 |
85.7 |
2.6 |
| Hexachloro-1,3-butadiene |
80.8 |
6.4 |
84.6 |
3.3 |
| 4-Chloro-3-methylphenol |
89.1 |
3.7 |
97.7 |
3.3 |
| Hexachlorocyclopentadiene |
90.9 |
8.6 |
88.9 |
3.2 |
| 2,4,6-Trichlorophenol |
89.5 |
3.6 |
99.0 |
3.2 |
| 2-Chloronaphthalene |
84.4 |
4.6 |
92.8 |
2.5 |
| Dimethyl phthalate |
90.4 |
4.6 |
101.2 |
2.7 |
| Acenaphthalene |
85.9 |
4.2 |
95.1 |
2.5 |
| 2,6-Dinitrotoluene |
91.0 |
4.0 |
101.1 |
3.3 |
| Acenaphthene |
86.9 |
3.8 |
95.2 |
3.1 |
| 2,4-Dinitrotoluene |
96.9 |
2.1 |
102.7 |
3.4 |
| Diethyl phthalate |
93.7 |
4.8 |
103.2 |
3.0 |
| 2-Methyl-4,6-dinitrophenol |
88.8 |
4.1 |
98.6 |
2.9 |
| Fluorene |
92.0 |
2.5 |
99.2 |
2.9 |
| Azobenzene |
89.7 |
4.7 |
99.3 |
3.1 |
| 4-Bromodiphenyl ether |
89.5 |
4.7 |
100.7 |
2.8 |
| Hexachlorobenzene |
92.7 |
4.3 |
100.6 |
3.1 |
| Phenanthrene |
94.0 |
4.1 |
101.0 |
2.9 |
| Anthracene |
94.7 |
3.1 |
101.4 |
3.3 |
| Carbazole |
97.1 |
3.1 |
108.1 |
3.5 |
| Dibutyl phthalate |
101.2 |
4.9 |
103.7 |
2.5 |
| Fluoranthene |
100.4 |
3.4 |
103.0 |
3.0 |
| Pyrene |
99.4 |
3.0 |
101.4 |
3.5 |
| Benzyl butyl phthalate |
112.4 |
0.8 |
104.2 |
2.3 |
| Benzanthracene |
94.0 |
3.8 |
103.2 |
4.5 |
| Bis(2-Ethylhexyl) phthalate |
109.7 |
3.8 |
106.9 |
3.3 |
| Chrysene |
94.9 |
3.1 |
103.3 |
4.2 |
| Di-n-octyl phthalate |
111.0 |
4.2 |
110.6 |
3.6 |
| Benzo[b]fluoranthene |
96.0 |
6.8 |
105.5 |
4.3 |
| Benzo[k]fluoranthene |
104.6 |
5.8 |
104.0 |
5.3 |
| Benzo[a]pyrene |
94.6 |
6.0 |
105.4 |
4.8 |
| Dibenz[a,h]anthracene |
98.5 |
8.6 |
109.6 |
6.9 |
| Benzo[g,h,i]perylene |
98.2 |
8.3 |
110.0 |
5.7 |
Results
The results of the instrumental and evaporation analysis are shown in Table 3. For each of the two evaporation techniques, a total of n = 6 replicates were examined and the averages are shown.
Both recovery and RSD values were computed by comparing the peak area response of p-Terphenyl in a standard sample and the processed samples and by creating an RF. Subsequently, this RF was used to volumetrically standardize the outcomes for the processed samples in comparison to the standard one.
Conclusion
The latest TurboVap® II evaporation system offers exceptional recoveries and RSDs for a broad range of semi-volatile compounds.
With two choices available for 50 or 200 mL tube sizes and either 1.0 or 0.5 mL end-point, the system can be utilized with solvent extracts taken from a broad range of extraction techniques, such as Solid Phase Extraction, Continuous Liquid-Liquid Extraction, Liquid-Liquid Extraction, Supported Liquid Extraction, Ultrasonic Extraction, Pressurized Fluid Extraction, and TLCP Extracts.
About Biotage
Biotage offers solutions, knowledge, and experience in the areas of analytical chemistry, medicinal chemistry, peptide synthesis, separation and purification. Customers include pharmaceutical, clinical and biotech companies, companies within the food industry and leading academic and government institutes. The company is headquartered in Uppsala and has offices in the US, UK, China, S. Korea, India, and Japan. Biotage has approx. 460 employees and had sales of 1,101 MSEK in 2019. Biotage is listed on the NASDAQ Stockholm.
Aim
Biotage is a global Life Science company that develops innovative and effective solutions for separation within organic and analytical chemistry, as well as for industrial applications. We help shape the sustainable science of tomorrow and our future society for the benefit of humankind. Our mission is to help our customers to make the world more sustainable, healthier, and cleaner.
This is Biotage
Customers
The company has a strong customer base of industry and academic partners, which include the world’s top 20 pharmaceutical companies and prestigious academic and government institutes such as the US National Institutes of Health, the US Centers for Disease Control and Prevention and the Karolinska Institute in Sweden.
Biotage products are used by public authorities, academic institutions, contract research and contract manufacturing organizations, as well as the pharmaceutical and food industries. The Biotage products rationalize the workflow of customers and reduce their impact on the environment, for example by using a lower volume of solvents. Customers use Biotage products e.g. in their development of new medicines and to analyze samples from hospital patients, in forensic laboratories, or for the analysis of environmental and food samples. Biotage also offers products to remove undesired substances from, for example, pharmaceuticals during the manufacturing process.
Locations
Headquartered in Uppsala, Sweden, Biotage AB also has facilities in Lund, Sweden; Charlotte, NC, USA; San Jose, CA, USA; Salem, NH, USA; Cardiff, UK; Bundang, S. Korea; New Dehli, India; Tokyo and Osaka, Japan; and Shanghai, China.
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