A method for simultaneously analyzing different types of liquid crystal monomers based on GC-APCI-MS / MS technology

Abstract

The invention discloses a method for simultaneously analyzing different types of liquid crystal monomers based on GC-APCI-MS / MS technology, which belongs to the technical field of analytical chemistry. Anhydrous sodium sulfate and recovery rate indicators PCB-28-d4 and PCB-114-d4 are added to a sample to be tested, a mixed solution of dichloromethane and n-hexane is added, the mixture is evenly mixed, ultrasonic extraction is performed, supernatant is obtained by centrifugation, the above steps are repeated, the extracts are combined, concentrated, and an internal standard is added. 13 C 12 ‑PCB‑141 was added to the fixed volume and detected by GC‑APCI‑MS / MS technology. The detection limit range of the method of the present invention for LCMs was 0.01‑0.2 ng / mL, the quantification limit range was 0.05‑1.2 ng / mL, and the repeatability of the quantitative lower limit for 6 consecutive injections was within 10% (0.26%‑7.01%).

Description

Technical Field

[0001] The present invention relates to the technical field of analytical chemistry, and in particular to a method for simultaneously analyzing different types of liquid crystal monomers based on GC-APCI-MS / MS technology. Background Art

[0002] Liquid crystal monomers (LCMs) are a class of synthetic organic chemicals that usually have phenyl-based structural units and contain alkyne, cyclohexyl, ester, cyano and fluorine substituents. Due to their unique physical and chemical properties, they are widely used as key technical materials for the production of liquid crystal displays (LCDs) and are embedded between the glass layer and electrical control components of LCDs. Since liquid crystal monomers are not chemically bonded to the substrate in LCDs, they are easily released into the environment during the production of LCDs and the disassembly, recycling and terminal treatment of discarded LCDs. Existing studies have shown that liquid crystal monomers can destroy antioxidant enzymes in catfish and reduce the survival ability of bacteria. Some studies have confirmed that liquid crystal monomers have genetic toxicity similar to dioxins. Other researchers have estimated the persistence and bioaccumulation of liquid crystal monomers and pointed out that liquid crystal monomers will show difficulty in degradation and long-distance migration after entering the environment, and have been detected in environmental samples.

[0003] In recent years, the application of smartphones, computers, TVs, tablets and solar panels has increased dramatically. As early as 2018, the global shipment of LCD panels reached 198 million m2. 2 With the continuous development and progress of science and technology, the replacement of electronic products has accelerated, and the amount of electronic waste has increased dramatically. A large number of LCDs have entered the environment through various treatment and disposal links of electronic waste. Studies have detected liquid crystal monomers in electronic waste dismantling areas, surface sediments in typical areas, and serum of occupational groups. The concentration of liquid crystal monomers detected in electronic waste dismantling areas is equivalent to that of polybrominated diphenyl ethers. Liquid crystal monomers are considered to be a new type of pollutants, and accurate qualitative and quantitative analysis of them is indispensable. At present, there are few studies on the environmental issues of liquid crystal monomers, and the existing analytical techniques have certain shortcomings and deficiencies, such as time-consuming operation, high solvent consumption, low sensitivity, and poor repeatability. Therefore, it is necessary to provide a quantitative method based on atmospheric pressure chemical ionization source gas chromatography-mass spectrometry (GC-APCI-MS / MS) to simultaneously analyze different types of liquid crystal monomers with high sensitivity and precision. Summary of the invention

[0004] In view of the problems and shortcomings of the prior art, the present invention provides a quantitative method for simultaneously analyzing three types (7 BAs, 2 CBAs and 15 FBAs) of liquid crystal monomers based on GC-APCI-MS / MS technology with high sensitivity and precision.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The invention provides a method for simultaneously analyzing different types of liquid crystal monomers based on GC-APCI-MS / MS technology. Anhydrous sodium sulfate and recovery rate indicator PCB-28-d4 (2,4,4'-trichlorobiphenyl-d4) and PCB-114-d4 (2,3,4,4',5-pentachlorobiphenyl-d4) are added to a sample to be tested, a mixed solution of dichloromethane and n-hexane is added, the mixture is evenly mixed and then ultrasonically extracted, the supernatant is taken after centrifugation, the mixed extraction solution is added again, the extraction steps are repeated for a total of 3 times, the extracts are combined, concentrated, and an internal standard is added. 13 C 12 -PCB-141 (2,2',3,4,5,5'-hexachlorobiphenyl) and fixed volume, and detected by GC-APCI-MS / MS technology.

[0007] In addition to extraction and concentration, the prior art also passes the concentrated supernatant through columns of Florisil and anhydrous sodium sulfate, and generally activates the column with 25 mL of dichloromethane and 25 mL of n-hexane, and rinses with 20 mL of dichloromethane after loading. This process consumes a large amount of solvent and is time-consuming and labor-intensive. The pretreatment process of the present invention only includes two steps of extraction and concentration, and the overall operation is simple, time-consuming, and solvent consumption is small, which is suitable for the processing and detection of large quantities of samples.

[0008] Furthermore, the mass ratio of the sample to be tested to anhydrous sodium sulfate is 1:1.

[0009] Furthermore, the volume ratio of dichloromethane to n-hexane is 3:7.

[0010] Furthermore, an atmospheric pressure chemical ionization source (APCI positive mode) was used, the acquisition mode was the multiple reaction monitoring (MRM) mode, and the chromatographic column was an Rxi-5HT chromatographic column (15 m×0.25 mm×0.1 μm).

[0011] Furthermore, the gas chromatography conditions were as follows: the acquisition mode was the multiple reaction monitoring (MRM) mode, using an Rxi-5HT chromatographic column (15m×0.25mm×0.1μm), the column flow rate was 1.0mL / min, the programmed temperature was: initial temperature 80°C, maintained for 3min, increased to 360°C at a rate of 15°C / min, maintained for 5min; non-split injection, the injection volume was 1μL, and the carrier gas was high-purity helium.

[0012] Furthermore, the mass spectrometry conditions were: injection port temperature 360°C, ion source temperature 140°C, transfer line temperature 320°C, cone voltage 25V, and corona needle current 3.0μA.

[0013] Further, the liquid crystal monomers include 3VbcH, MeO3bcH, Pe3bcH, 2CB, 2O3cHdFP, 5MeB, 2OdF3B, MePVbcH, MeP3bcH, MeOdFP3bcH, 3cH2B, 8OCB, 2O2cHdFB, 2OdFP3bcH, 2F3T, 2O3cHdFB, 3OdFP3bcH, 2OdFP4bcH, 2bcHdFB, tFMeO-3cHtFT, tFPO-CF2-tF3T, 3bcHdFB, 4bcHdFB and 5bcHdFB.

[0014] The detection limit of the method of the present invention for 24 LCMs is in the range of 0.01-0.2 ng / mL, the quantitative limit is in the range of 0.05-1.2 ng / mL, and the repeatability of the quantitative lower limit for 6 consecutive injections is within 10% (0.26%-7.01%). The signal-to-noise ratio (S / N) of the detection limit is ≥3, and the S / N of the quantitative limit is ≥10.

[0015] The present invention discloses the following technical effects:

[0016] 1. The present invention provides for the first time a GC-APCI-MS / MS-based method for simultaneously analyzing three types of liquid crystal monomers (7 BAs (Biphenyls / bicyclohexyls and Analogs)), 2 CBAs (Cyano biphenyls and Analogs) and 15 FBAs (Fluorinated Biphenyls and Analogs)). APCI has the following advantages over EI used in existing analysis methods: sufficient ionization at atmospheric pressure, high sensitivity, soft ionization, generation of high-abundance (quasi) molecular ion peaks and characteristic spectra, and improved qualitative analysis capability.

[0017] 2. The present invention can basically achieve baseline separation of two isomers in the target substance, can accurately identify and quantify, and completely separate 24 target substances with good peak shape and high response.

[0018] 3. The detection method of the present invention has low detection limit and quantitative limit, a wide linear range of the standard curve (0.05-500 ng / mL), high sensitivity and stability.

[0019] 4. The sample pretreatment process of the present invention is simple, including only two steps of extraction and concentration. Compared with the prior art, the overall operation is simple and fast, with less solvent consumption, which is suitable for the processing and detection of large quantities of samples. It can perform qualitative and quantitative analysis on dust or particulate matter, and provides a more convenient and reliable method for further research on liquid crystal monomer substances in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 The chromatograms of 24 target compounds analyzed using the EI ion source in Comparative Example 1, wherein A is the TIC graph of compounds No. 1-6, 8-10, 13, 15, 16, 18, 19, 22-24, and B is the TIC graph of compounds No. 7, 11, 14, and 17;

[0022] Figure 2 Overlay of total ion current (TIC) of 24 liquid crystal monomers before parameter optimization;

[0023] Figure 3 It is an overlapping diagram of the total ion current (TIC) of 24 liquid crystal monomers under the optimal conditions, including 1.3VbcH, 2.MeO3bcH, 3.Pe3bcH, 4.2CB, 5.2O3cHdFP, 6.5MeB, 7.2OdF3B, 8.MePVbcH, 9.MeP3bcH, 10.MeOdFP3bcH, 11.3cH2B, 12.8OCB, 13.2O2cHdFB, 14.2OdFP3bcH, 15.2F3T , 16.2O3cHdFB, 17.3OdFP3bcH, 18.2OdFP4bcH, 19.2bcHdFB, 20.tFMeO-3cHtFT, 21.tFPO-CF2-tF3T, 22.3bcHdFB, 23.4bcHdFB, 24.5bcHdFB; among them, 7 types of Bas are numbered 1, 2, 3, 6, 8, 9, and 11, 2 types of CBAs are numbered 4 and 12, and the remaining 15 are all FBAs.

[0024] Figure 4 It is the ratio of the parameters of the quantitative ion of the target compound after optimization to those before optimization;

[0025] Figure 5 It is the ratio of the parameters of the target compound qualifier ion after optimization to those before optimization. DETAILED DESCRIPTION

[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0027] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0028] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0029] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0030] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0031] The term "linear range" of the present invention refers to the linear range of the standard curve.

[0032] The method for simultaneously analyzing different types of liquid crystal monomers based on GC-APCI-MS / MS technology provided by the present invention comprises: adding anhydrous sodium sulfate and standard products PCB-28-d4 (2,4,4'-trichlorobiphenyl-d4) and PCB-114-d4 (2,3,4,4',5-pentachlorobiphenyl-d4) to the sample to be tested, adding a mixed solution of dichloromethane and n-hexane, mixing evenly, performing ultrasonic extraction, centrifuging and taking supernatant, repeating the above extraction steps 3 times, combining the extracts, concentrating, and adding an internal standard 13 C 12 -PCB-141 and fixed volume, and detected by GC-APCI-MS / MS technology.

[0033] The analysis of the liquid crystal monomer of the present invention adopts gas chromatography-mass spectrometry technology, the ion source is atmospheric pressure chemical ionization source (APCI positive mode), the acquisition mode is multiple reaction monitoring (MRM) mode, and an Rxi-5HT chromatographic column (15m×0.25mm×0.1μm) is used. By preparing standard products of different concentrations, gas chromatography conditions and mass spectrometry conditions are established, and the programmed temperature, injection port temperature, ion source temperature, transmission line temperature, cone voltage, corona needle current and other conditions are further optimized to improve the sensitivity.

[0034] In the method of the present invention, the mass ratio of the sample to be tested to anhydrous sodium sulfate is 1:1.

[0035] In the method of the present invention, the volume ratio of dichloromethane to normal hexane is 3:7.

[0036] In the method of the present invention, the sample pretreatment method can be: for every 1g of the sample to be tested (preferably dust or particulate matter, etc., when the sample is dust, it is sieved through a 35-mesh sieve before weighing), 1g of anhydrous sodium sulfate and recovery indicator PCB-28-d4, PCB-114-d4 are added to the sample to be tested, and then 10mL of a mixed solution of dichloromethane: normal hexane (V:V=3:7) is added, and ultrasonic extraction is performed after mixing evenly, and a supernatant is obtained by centrifugation, and the above steps are repeated for a total of 3 times, and the 3 extracts are combined, and the extracts are concentrated to 0.5mL by rotary evaporation on a rotary evaporator, and an internal standard is added. 13 C 12 -PCB-141 and dilute to 1 mL, and detect using GC-APCI-MS / MS technology with the internal standard method.

[0037] In the method of the present invention, the ion source is an atmospheric pressure chemical ionization source (APCI positive mode), the acquisition mode is a multiple reaction monitoring (MRM) mode, and the chromatographic column is an Rxi-5HT chromatographic column (15m×0.25mm×0.1μm).

[0038] The gas chromatography conditions in the method of the present invention are as follows: the acquisition mode is the multiple reaction monitoring (MRM) mode, using an Rxi-5HT chromatographic column (15m×0.25mm×0.1μm), the column flow rate is 1.0mL / min, the program temperature is: the initial temperature is 80°C, maintained for 3min, increased to 360°C at a rate of 15°C / min, maintained for 5min. Non-split injection, the injection volume is 1μL, and the carrier gas is high-purity helium.

[0039] The mass spectrometry conditions in the method of the present invention are as follows: injection port temperature 360°C, ion source temperature 140°C, transmission line temperature 320°C, cone voltage 25V, and corona needle current 3.0μA.

[0040] In the method of the present invention, the preferred ion source is an atmospheric pressure chemical ionization source (APCI positive mode), the acquisition mode is a multiple reaction monitoring (MRM) mode, an Rxi-5HT chromatographic column (15m×0.25mm×0.1μm) is used, the column flow is 1.0mL / min, the initial temperature is 80°C, maintained for 3min, raised to 360°C at a rate of 15°C / min, and maintained for 5min. Non-split injection, the injection volume is 1μL, and the carrier gas is high-purity helium. The injection port temperature is 360°C, the ion source temperature is 140°C, the transmission line temperature is 320°C, the cone voltage is 25V, and the corona needle current is 3.0μA.

[0041] The method of the present invention is used to prepare liquid crystal monomer mixed standard solutions with different concentration gradients, and the solutions are analyzed by the established GC-APCI-MS / MS technology to obtain the linear correlation coefficient R of the standard curve equation. 2 The values ​​of are all greater than 0.992.

[0042] The liquid crystal monomers in the method of the present invention include 3VbcH, MeO3bcH, Pe3bcH, 2CB, 2O3cHdFP, 5MeB, 2OdF3B, MePVbcH, MeP3bcH, MeOdFP3bcH, 3cH2B, 8OCB, 2O2cHdFB, 2OdFP3bcH, 2F3T, 2O3cHdFB, 3OdFP3bcH, 2OdFP4bcH, 2bcHdFB, tFMeO-3cHtFT, tFPO-CF2-tF3T, 3bcHdFB, 4bcHdFB and 5bcHdFB.

[0043] The detection limits of 24 LCMs using the method of the present invention ranged from 0.01 to 0.2 ng / mL, the quantitative limits ranged from 0.05 to 1.2 ng / mL, and the repeatability of the quantitative lower limit for 6 consecutive injections was within 10% (0.26% to 7.01%). The signal-to-noise ratio (S / N) of the detection limit was ≥3, and the S / N of the quantitative limit was ≥10.

[0044] Example 1

[0045] Establish and optimize gas chromatography and mass spectrometry conditions:

[0046] Liquid crystal monomers were analyzed by gas chromatography-mass spectrometry, with atmospheric pressure chemical ionization (APCI positive mode) as the ion source, multiple reaction monitoring (MRM) as the acquisition mode, Rxi-5HT column (15m×0.25mm×0.1μm) as the column flow rate of 1.0mL / min, and the temperature program was optimized and determined according to the separation degree and retention time between the analytes: initial temperature 80℃, maintained for 3min, increased to 360℃ at a rate of 15℃ / min, maintained for 5min. Non-split injection, injection volume of 1μL, carrier gas was high-purity helium. According to the signal-to-noise ratio, peak area, response value and peak shape of the analyte, the injection port temperature (340-360℃), ion source temperature (130-150℃), transmission line temperature (320-340℃), cone voltage (10-80V) and corona needle current (0.1-30uA) were optimized respectively, and the optimal conditions were determined: injection port temperature 360℃, ion source temperature 140℃, transmission line temperature 320℃, cone voltage 25V, and corona needle current 3.0μA.

[0047] Pretreatment of samples to be tested:

[0048] Weigh 1g of the sample to be tested (taking dust as an example, sieve it through a 100-mesh sieve before weighing). Add 1g of anhydrous sodium sulfate, add 100μL of recovery rate indicators PCB-28-d4 and PCB-114-d4, let it stand for 1 hour, then add 10mL of a mixed solution of dichloromethane: n-hexane (V:V=3:7), mix well, and perform ultrasonic extraction for 5min. Centrifuge at 3500rmp, 4°C, and 5min to obtain the supernatant. Repeat the above steps 3 times, combine the 3 extracts, perform rotary evaporation on a rotary evaporator, concentrate to 0.5mL, and add the internal standard. 13 C 12 -PCB-141 was used as an internal standard and the volume was adjusted to 1 mL.

[0049] After the pretreatment of the sample to be tested is completed, the internal standard method is used for detection using GC-APCI-MS / MS through the previously established gas chromatography conditions and mass spectrometry conditions, and the sample is qualitatively and quantitatively analyzed in combination with the standard calibration curve equation.

[0050] The overlay of the total ion current (TIC) of 24 liquid crystal monomers under the optimal conditions is shown in Figure 3 ,Depend on Figure 3 It can be seen that the method of the present invention can basically achieve baseline separation of the two isomers in the target substance, and can accurately determine the quality and quantity ( Figure 3 Among them, substances No. 17 and No. 18 are isomers), and the 24 target substances are completely separated, with good peak shape and high response.

[0051] The matrix solution was prepared by using the supernatant obtained by the same sample pretreatment steps as above with the standard soil without liquid crystal monomer. The specific operation was as follows: 1 g of standard soil sample was weighed and placed in a 50 mL centrifuge tube, 10 mL of a mixed solution of dichloromethane:n-hexane (V:V=3:7) was added, and then ultrasonic extraction was performed for 5 min. The supernatant was obtained by centrifugation at 3500 rpm and 4°C for 5 min. The liquid crystal monomer standard was diluted with the concentrated supernatant to prepare liquid crystal monomer mixed matrix spiked solutions with different concentration gradients (concentration gradients of 0.05, 1, 10, 100, 250, 500 ng / mL). The standard curve equation was analyzed by the established GC-APCI-MS / MS technology, and the linearity of the correlation coefficient R 2 The values ​​of are all greater than 0.992.

[0052] The recoveries and relative standard deviations of the 24 target compounds at different spike concentrations (low, medium and high concentrations) are shown in Table 1.

[0053] Table 1 Spiked recoveries and relative standard deviations of 24 target compounds at different spike concentrations

[0054]

[0055]

[0056] The target compound information and the linear equation of the standard curve under the optimal conditions and their correlation coefficients are shown in Table 2. The detection limit range of 24 LCMs using the method of the present invention is: 0.01-0.2 ng / mL, the quantitative limit range is: 0.05-1.2 ng / mL, and the repeatability of the quantitative lower limit of 6 consecutive injections is within 10% (0.26%-7.01%). The signal-to-noise ratio (S / N) of the detection limit is ≥3, and the S / N of the quantitative limit is ≥10.

[0057] Table 2 Target compound information and standard curve linear equation and its correlation coefficient

[0058]

[0059]

[0060] Comparative Example 1

[0061] In this comparative example, 24 liquid crystal monomers were analyzed using a gas chromatography-mass spectrometry system (traditional EI ion source). In SIM mode (Selected ion Monitor), two SIM methods were established to analyze the 24 liquid crystal monomers in order to distinguish target substances with similar retention times. Figure 1 (A) and (B), however, not all substances can be analyzed simultaneously. Figure 3 It shows that the analysis technology of the present invention can analyze target compounds with similar retention times, and can even well separate isomers (No. 17 and 18). Therefore, the analysis technology of the present invention can analyze 24 liquid crystal monomers at the same time, with a high response value and a low baseline.

[0062] Comparative Example 2

[0063] Compared with the optimal parameter conditions, the chromatographic peaks of 24 liquid crystal monomers under non-optimal conditions (injection port temperature 350℃, ion source temperature 150℃, transfer line temperature 300℃, cone voltage 40V, corona needle current 5μA) have burrs, and the peak areas, response values ​​and signal-to-noise ratios of all target compounds are relatively low, which will increase the detection limit and quantification limit, thereby affecting the detection sensitivity. Figure 2 and Figure 3 They are the total ion current graphs of the target compound at the same concentration (10 ng / mL) before and after the optimization parameters. In general, the response value under the optimized parameter conditions is one order of magnitude higher than that before optimization. Figure 4 and Figure 5 The peak area, response value and signal-to-noise ratio of the quantitative and qualitative ions of each substance before and after optimization are shown. It is obvious that the optimized parameters have been improved by different multiples.

[0064] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for simultaneously analyzing different types of liquid crystal monomers based on GC-APCI-MS / MS technology, characterized in that: Add anhydrous sodium sulfate and recovery rate indicators PCB-28-d4 and PCB-114-d4 to the sample to be tested, add a mixed solution of dichloromethane and n-hexane, mix well, extract by ultrasonication, centrifuge to obtain the supernatant, add the mixed extraction solution again, repeat the above extraction steps, combine the extracts, concentrate, and add the internal standard 13 C 12 -PCB-141 and fixed volume, using GC-APCI-MS / MS technology for detection; The mass ratio of the sample to be tested to anhydrous sodium sulfate is 1:1; The volume ratio of dichloromethane to n-hexane is 3:7; An atmospheric pressure chemical ionization source was used, the acquisition mode was multiple reaction monitoring mode, and the chromatographic column was an Rxi-5HT column, 15m×0.25mm×0.1μm; Gas chromatography conditions: The acquisition mode was multiple reaction monitoring mode, using an Rxi-5HT column, 15m×0.25mm×0.1μm, with a column flow rate of 1.0mL / min, and a temperature program of: initial temperature 80°C, maintained for 3min, increased to 360°C at a rate of 15°C / min, maintained for 5min; non-split injection, injection volume 1μL, and carrier gas was high-purity helium; Mass spectrometry conditions: injection port temperature 360°C, ion source temperature 140°C, transfer line temperature 320°C, cone voltage 25 V, corona needle current 3.0 μA; The liquid crystal monomer includes , referred to as 3VbcH, , referred to as MeO3bcH, , referred to as Pe3bcH, , referred to as 2CB, , referred to as 2O3cHdFP, , referred to as 5MeB, , referred to as 2OdF3B, , referred to as MePVbcH, , referred to as MeP3bcH, , referred to as MeOdFP3bcH, , referred to as 3cH2B, , referred to as 8OCB, , referred to as 2O2cHdFB, , referred to as 2OdFP3bcH, , referred to as 2F3T, , referred to as 2O3cHdFB, , referred to as 3OdFP3bcH, , referred to as 2OdFP4bcH, , referred to as 2bcHdFB, , referred to as tFMeO-3cHtFT, , referred to as tFPO-CF2-tF3T, , referred to as 3bcHdFB, , referred to as 4bcHdFB and , abbreviated as 5bcHdFB.

Images