1. bookTom 29 (2020): Zeszyt 2 (August 2020)
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eISSN
2719-9509
Pierwsze wydanie
01 Jan 1992
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Otwarty dostęp

Analysis of α-Tocopherol in Tobacco and Cigarette Smoke

Data publikacji: 25 Sep 2020
Tom & Zeszyt: Tom 29 (2020) - Zeszyt 2 (August 2020)
Zakres stron: 57 - 65
Otrzymano: 25 Mar 2020
Przyjęty: 29 May 2020
Informacje o czasopiśmie
License
Format
Czasopismo
eISSN
2719-9509
Pierwsze wydanie
01 Jan 1992
Częstotliwość wydawania
4 razy w roku
Języki
Angielski
INTRODUCTION

The presence of α-tocopherol in tobacco seed oil was indicated in a report published as early as 1945 (1). Numerous other reports (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15) indicate the presence of α-tocopherol in tobacco and in cigarette smoke, some of these were reporting qualitative results (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12), others reported quantitative results (13, 14, 15). Unfortunately, most reports regarding quantitative analysis of α-tocopherol were not published but only presented at conferences or communicated in internal company publications. Also, various procedures for the analysis of tocopherols in a variety of matrices are reported in the literature (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36). These methods include high performance liquid chromatography (HPLC) analysis with fluorescence detection (FD) (16), HPLC with ultra violet (UV) detection at various wavelengths (17, 18, 19), tandem mass spectrometry (MS/MS) detection (33, 34, 35), as well as gas chromatography coupled with mass spectrometry (GC/MS) analysis (22). Depending on the matrix and the desired sensitivity of the analysis a specific procedure must be selected. However, the available methods were not found adequate for the analysis of both α-tocopherol and α-tocopheryl acetate in tobacco and in cigarette smoke due to using at the same time UV detection and MS/MS detection. The advantage of UV detection is its excellent reproducibility; a disadvantage is sometimes a lack of selectivity. On the other hand, MS/MS detection is highly selective, but frequently affected by larger reproducibility errors compared to UV analysis. The combination of the two techniques offer both good reproducibility and selectivity of the analysis. A technique using both UV and MS/MS detection is desired for the analysis of these compounds with the elimination of potential interferences from the tobacco or smoke matrix. The present study describes an original method adequate for this purpose and the results for tobacco and smoke. The importance of knowing the level of α-tocopherol in tobacco is related to the fact that the compound is one of the E vitamins, and that it has antioxidant properties. It was of interest to provide information regarding the level of α-tocopherol in tobacco and cigarette smoke as compared to a recommended dietary allowance for vitamin E of 15 mg/day (for an adult). In addition, α-tocopheryl acetate, was analyzed in the study but found absent in tobacco and cigarette smoke. This compound has been associated with EVALI (Electronic Cigarette, or Vaping, product use-Associated Lung Injury), and was reported in certain counterfeit products (37, 38, 39). However, there is no report of α-tocopheryl acetate or similar compounds in legitimate commercial e-vaping products (37).

EXPERIMENTAL
Materials

α-Tocopherol, α-tocopheryl acetate, 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (Uvitex-OB), and 2,6-di-tert-butyl-4-methylphenol (BHT) as well as acetonitrile, formic acid, isopropanol, and methanol were purchased from Sigma-Aldrich (St. Louis, MO, USA).

The GC vials used were 2-mL with screw top caps with septa. Also 4-mL vials with screw top caps with septa were used. Polyvinylidene difluoride (PVDF) filters of 0.45-μm (Whatman Autovial, GE Healthcare, Little Chalfort, UK) were used for filtration.

Instrumentation

Two HPLC systems were used for the analysis. One system with UV detection was a 1260–1290 HPLC system from Agilent (Wilmington, DE, USA). This HPLC system consisted of a binary pump, autosampler, column thermostatted compartment, and UV detector (diode array).

The peak integration was performed with OpenLab ChemStation. The other system was an Agilent 1200 HPLC binary system that consisted of a binary pump, an autosampler with cooling capability, and a column thermostatted compartment coupled with an API-5000 triple quadrupole mass spectrometer (AB Sciex, Framing-ham, MA, USA) controlled using Analyst 1.6.2 software. The peak integration was performed with MultiQuant 3.0.1 software. Both HPLC systems were equipped with a Zorbax Eclipse XDB-C18 column, 4.6 × 250 mm, 5 μm, also from Agilent. An ultrasonic bath 5510 from Branson (Danbury, CT, USA) was used. For smoking, a Cerulean SM 450 smoking machine (Cerulean, Linford Wood East, UK) has been used. Tobacco moisture was measured with halogen moisture analyzer HE53 (Mettler Toledo, Greifensee, Switzerland).

Standard preparation

Two initial standard stock solutions - one containing 98.4 μg/mL α-tocopheryl acetate and the other 100.6 μg/mL α-tocopherol - were prepared in methanol. Each stock solution also contained 5604.0 μg/mL BHT. BHT is used as an antioxidant to prevent tocopherol and tocopheryl acetate oxidation. The stock solutions were also used as the highest standard.

The Level 2 of dilution was prepared by mixing equal volumes of the two stock solutions and the other standards were obtained by successive dilutions with methanol. 20 μL of Uvitex-OB internal standard (I.S.) were added to 1 mL of each standard and the resulting solution concentrations for the calibration is given in Table 1. The concentration of the I.S. in each solution was 525.6 μg/mL.

The list of standards in μg/mL(the addition of 10 μL I.S. slightly changes the final concentrations from the values in the stock solution).

Compound Standard in μg/mL

Level 1 Level 2 Level 3 Level 4 Level 5 Level 6 Level 7 Level 8 Level 9 Level 10
α-Tocopherol 98.63 49.31 24.66 12.33 6.16 3.08 1.54 0.77 0.39 0.19
α-Tocopherol acetate 96.47 48.24 24.12 12.06 6.03 3.01 1.51 0.75 0.38 0.19
Sample preparation

Before the analysis, the moisture of each tobacco sample was measured. The analysis of tobacco was performed on tobacco “as is”, and 200 mg (± 5 mg) tobacco was precisely weighed in a 4-mL vial. 2 mL methanol containing 560.4 μg/mL BHT, and 40 μL internal standard were added to the vial. The capped vials were heated at 78 °C for 30 min with occasional agitation. After cooling, at room temperature the solutions were filtered through a 0.45-μm pore size PVDF filter and submitted for analysis.

For the analysis of cigarette smoke, smoking was performed using 35 mL puff volume, 2 s puff duration, and 60 s puff interval, with the cigarette filters not having the ventilation blocked (indicated as ISO (International Organization for Standardization)). The machine airflows were tuned for ISO conditions (40, 41). The smoking was performed at Eurofins/Lancaster Labs. Smoke from five cigarettes was collected in each run on a 44-mm diameter Cambridge pad. The pads were further extracted on a mechanical shaker for 30 min with 5 mL methanol containing 560.4 μg/mL BHT, and 100 μL solution of internal standard (Uvitex-OB) were added. An aliquot from the extract was filtered through a 0.45-μm pore size PVDF filter and submitted for HPLC analysis.

HPLC separation and detection

The HPLC separation was performed using the gradient with solvent A being acetonitrile and solvent B isopropanol. For the MS/MS analysis the acetonitrile also contained 0.1% formic acid. The gradient timetable is described in Table 2.

Timetable for the gradient HPLC separation.

Run time (min) Solvent A % Solvent B % Detection
0.0 85.0 15.0 On
15.0 85.0 15.0 On
15.5 40.0 60.0 On
16.0 40.0 60.0 Off
18.5 40.0 60.0 Off
19.0 85.0 15.0 Off
25.0 85.0 15.0 Off

The detection by UV absorption was performed at 210 nm and the injection volume was 20 μL. The flow rate was 1.5 mL/min. For the MS/MS, because the flow rate of 1.5 mL/min was too high, the effluent from the chromatographic column was split, and only 0.5 mL/min were introduced into the mass spectrometer. Also, the injection volume was 10 μL.

The detection was kept on only for 16 min, the last part of the gradient being used to elute highly hydrophobic compounds from tobacco or smoke that have a long retention time in the separation. The chromatogram of standard Level 5 for the HPLC separation with UV detection is indicated in Figure 1.

Figure 1

Chromatogram of standard Level 5 (6.16 μg/mL α-tocopherol and 6.03 μg/mL α-tocopheryl acetate).

The MS/MS detection using electrospray ionisation (ESI) was performed in multiple reaction monitoring (MRM) positive mode. The transitions utilized for detection are indicated in Table 3. The table also indicates the collision energy that was different for each analyte.

Parameters for the MS/MS detection.

Compound Ion for Q1 Ion for Q3 Time (ms) CE3 (V)
α-Tocopherol 431.4 165.1 200 38.0
α-Tocopheryl acetate 473.4 165.1 200 52.0
Uvitex-OB (I.S.) 431.5 415.3 200 49.0

The other parameters for the MS/MS detection included:

Declustering potential DE = 150 V,
Entrance potential = 13 V,
Collision gas (N2) CG = 6 mL/min,
Curtain gas CUR = 10 mL/min,
Ion spray voltage IS = 4000 V,
Temperature TE = 600 °C,
Ion source gas 1 GS1 = 35 mL/min,
Ion source gas 2 GS2 = 30 mL/min.

The chromatogram for the extracted ions of the analyzed compounds in Level 5 standard is shown in Figure 2.

Figure 2

Extracted ion chromatograms for the compounds in standard Level 5 (6.16 μg/mL α-tocopherol and 6.03 μg/mL α-tocopheryl acetate).

Quantitation using UV detection

For UV detection, considering the stability of the UV response, the quantitation for the two analytes was performed using calibrations of amount of the analyte versus the peak area of the analyte (no normalization by the internal standard). The internal standard was used only to verify the repeatability of the chromatographic process. The analytes concentrations in standards were those indicated in Table 1.

The calibration curves were linear and are shown in Figure 3 for α-tocopherol and in Figure 4 for α-tocopheryl acetate.

Figure 3

Calibration curve for α-tocopherol with UV detection.

Figure 4

Calibration curve for α-tocopheryl acetate with UV detection.

The coefficients a and b for the calibration curves of the form Y = a X + b, where Y is the concentration of the analyte and X is the peak area are given in Table 4.

Coefficients for the calibration curves Y = a X + b and of R2 used in UV quantitation.

Compound a b R2
α-Tocopherol 0.022401 −0.05633 1.00
α-Tocopheryl acetate 0.022655 −0.05204 1.00
Quantitation using MS/MS detection

For the MS/MS detection, the quantitation for the two analytes was performed using calibrations of the amount of the analyte versus the normalized peak area of the analyte by the area of the internal standard. The calibration curves were linear and are shown in Figure 5 for α-tocopherol and in Figure 6 for α-tocopheryl acetate.

Figure 5

Calibration curve for α-tocopherol with MS/MS detection.

Figure 6

Calibration curve for α-tocopheryl acetate with MS/MS detection.

The coefficients a and b for the calibration curves of the form Y = a X + b, where Y is the concentration of the analyte and X is the peak area of the standard normalized by the area of the internal standard are given in Table 5.

Coefficients for the calibration curves Y = a X + b and of R2 used in MS/MS quantitation.

Compound a b R2
α-Tocopherol 34.2270 −1.00506 0.9997
α-Tocopheryl acetate 10.7472 −1.39160 0.9997
Method validation

Both LC-UV and LC-MS/MS methods for α-tocopherol and α-tocopheryl acetate analysis can be considered as having good specificity. For the UV detection, retention time is basically the only criterion for selectivity, but for the MS/MS detection, besides the retention time are the masses of the ion for Q1 (for the parent ion) as the ion for Q3 (for the daughter ion).

The validation was further performed regarding limits of detection (LOD) and limits of quantitation (LOQ), linearity range, precision and intermediate precision, spike/recovery, accuracy, as well as solutions stability (see e.g. (42)).

The application of the procedure of considering LOD = 3 × SD (SD = standard deviation of the lowest standard) (42) would indicate from the SD values for α-tocopherol (SD = 0.008 μg/mL, three replicates) and for α-tocopheryl acetate (SD = 0.001 μg/mL, three replicates) that LOD = 0.024 μg/mL for tocopherol and LOD = 0.003 μg/mL for tocopheryl acetate (the LOQ values are three times higher). However, these values are not realistic since the true measurements are not feasible at these levels. For this reason, the limit of quantitation (LOQ) can be considered as equal with the lowest standard for both UV detection and MS/MS detection, and the values are indicated in Table 6.

The values for LOQ for α-tocopherol and α-tocopheryl acetate in μg/mL standard solution and per g of sample.

Compound LOQ solution (μg/mL) LOQ sample (μg/g)
α-Tocopherol 0.19 1.9
α-Tocopheryl acetate 0.19 1.9

Considering that the samples for tobacco analysis are prepared using a 1/10 dilution in methanol, the LOQ per g of sample is 10 times lower. The same LOQ values were considered for smoke analysis.

The precision of the method can be considered very good, based on the R2 values of all the calibrations. However, samples were not injected a sufficient number of times to generate specific precision levels.

The recovery of α-tocopherol from the tobacco matrix was evaluated by performing a second extraction of the tobacco sample. For this reason, after the first extraction and the filtration of the liquid, the remaining solid tobacco was placed on a filter paper and, as much as possible, the remaining liquid was adsorbed on the paper. After that the extracted tobacco was allowed to dry. From this material, 100 mg were weighed in a 2-mL GC vial and 1 mL methanol containing BHT, plus 20 μL solution of the internal standard were added. The sample was heated at 78 °C for 30 min with occasional agitation and after cooling the solutions were filtered through a 0.45-μm pore size PVDF filter and submitted for the HPLC analysis. The procedure was performed for four tobacco samples. The results are indicated in Table 7.

Percent recovery of α-tocopherol in a second extraction from total in the sample.

Experiment First extraction (μg/g) Second extraction (μg/g) % in second extraction
1 749.16 15.70 2.05
2 812.54 18.66 2.24
3 768.32 14.57 1.86
4 808.30 16.14 1.96

As indicated in Table 7, only a very small proportion of α-tocopherol was recovered in a second extraction, indicating a very good recovery of the analytical technique.

Based on literature reports (35) in the presence of BHT, the solutions are stable up to two weeks when stored at −5 °C.

RESULTS AND DISCUSSION
Sample description

The list of tobaccos evaluated for the level of α-tocopherol and the potential presence of α-tocopheryl acetate is given in Table 8. The table also indicated wether cigarettes were made or not made from the corresponding tobacco.

List of tobaccos evaluated in this study, the moisture in % and the indication if cigarettes were available.

No. Sample acronym a Description Moisture (%) Cigarettes available
1 FC L (1) Common blend of lower stalk flue-cured 6.44 No
2 FC U (1) Common blend of upper stalk flue-cured 6.71 No
3 FC L (2) Eastern NC belt, lower stalk (lug) flue-cured 6.84 Yes
4 FC U (2) Eastern NC belt, upper stalk (leaf & some tips) flue-cured 7.35 Yes
5 FC L (3) South Carolina belt, lower stalk (lug) flue-cured 7.86 Yes
6 FC U (3) South Carolina belt, upper stalk (leaf & some tips) flue-cured 7.11 Yes
7 FC off L Brazil, lower stalk (lugs & primings) flue-cured 8.13 Yes
8 FC off U Brazil, upper stalk (leaf & tips) flue-cured 9.01 Yes
9 Bu L (1) Common blend of lower stalk Burley 6.36 No
10 Bu U (1) Common blend of upper stalk Burley 7.17 No
11 Bu L (2) Kentucky & Tennessee, lower stalk (flyings & cutters) Burley 6.93 Yes
12 Bu U (2) Kentucky & Tennessee, upper stalk (leaf) Burley 6.99 Yes
13 Bu L (3) North Carolina & Virginia, lower stalk (flyings & cutters) Burley 8.09 Yes
14 Bu U (3) North Carolina & Virginia, upper stalk (leaf) Burley 8.33 Yes
15 Bu off L Malawi, lower stalk (flyings & rcutters) Burley 8.19 Yes
16 Bu off U Malawi, upper stalk (leaf) Burley 8.24 Yes
17 Or (1) Common blend of Oriental 6.64 No
18 Or (2) Common blend of Oriental 6.23 No
19 Or Sa U Turkey, good quality middle to upper stalk, Samsun Oriental 8.40 Yes
20 Or Iz U Turkey, good quality middle to upper stalk, Izmir Oriental 6.87 Yes
21 Commercial Tobacco blend 7.21 Yes
22 3R4F Tobacco blend 6.86 Yes

The number in parentheses indicates tobaccos of the same type but from different sources.

The cigarettes were manufactured in the R.J. Reynolds Tobacco Co. Fabrication Laboratory to achieve a draft with perforated filter holes closed of about 155 mm H2O and a draft with holes open of about 125 mm H2O and different tobacco weights, with cigarette length: 83 mm, rod length: 56 mm, filter length: 27 mm, and circumference: 24.48 mm. The cigarettes had cellulose acetate filters with segment draft of about 100 mm H2O and laser perforations.

Tobacco analysis

The analysis was performed for both α-tocopherol and for α-tocopheryl acetate. However, α-tocopheryl acetate was not detected in tobacco. The results of α-tocopherol as measured in the tobacco samples are given in Table 9. The results from Table 9 indicate that flue-cured tobaccos have typically higher levels of α-tocopherol than Burley and Oriental tobaccos with the upper stalk leaves slightly higher in α-tocopherol compared to the lower stalk leaves. Oriental and Burley tobacco had about the same range of levels of the compound, with Samsun Oriental having the lowest level.

Average α-tocopherol levels in μg/g tobacco as measured using the UV detection.

Sample No. Sample acronym a (μg/g) “as is” (μg/g) “dry base” RSD (%)
1 FC L (1) 731.18 778.26 0.27
2 FC U (1) 857.27 914.80 1.92
3 FC L (2) 760.38 812.39 2.09
4 FC U (2) 823.72 884.26 1.92
5 FC L (3) 778.92 840.15 1.93
6 FC U (3) 823.06 881.57 2.53
7 FC off L 746.77 807.48 2.86
8 FC off U 764.48 833.36 2.65
9 Bu L (1) 231.93 246.68 0.24
10 Bu U (1) 336.85 361.00 0.81
11 Bu L (2) 396.24 423.70 0.54
12 Bu U (2) 599.52 641.43 2.80
13 Bu L (3) 267.59 289.24 2.54
14 Bu U (3) 284.40 308.09 0.56
15 Bu off L 327.57 354.40 0.92
16 Bu off U 255.28 276.32 0.37
17 Or (1) 296.70 316.40 0.65
18 Or (2) 267.31 283.97 0.08
19 Or Sa U 181.74 197.00 1.31
20 Or Iz U 427.01 456.35 0.37
21 Commercial 510.19 546.97 0.53
22 3R4F 404.30 432.03 0.31

The number in parentheses indicates tobaccos of the same type but from different sources.

The results for the same analysis performed using the MS/MS detection generated very similar results. A graph showing the correlation between the UV data and the MS/MS data is given in Figure 7.

Figure 7

Correlation between the results for α-tocopherol analysis by UV detection and by mass spectrometry detection, expressed in μg/g tobacco.

Smoke analysis

The total particulate matter (TPM) results in g for five cigarettes smoked under ISO type conditions are indicated in Table 10.

The TPM in g generated from 5 cigarettes smoked under ISO type conditions and the average results for α-tocopherol in μg/mg in the collected TPM as obtained by the analysis with UV detection.

Sample No. Sample acronym a TPM, Repetition 1 (g) TPM, Repetition 2 (g) Average α-tocopherol in TPM (μg/mg) RSD (%)
3 FC L (2) 0.0668 0.0639 3.35 0.38
4 FC U (2) 0.0794 0.0816 3.98 1.11
5 FC L (3) 0.0534 0.0559 4.17 3.60
6 FC U (3) 0.0818 0.0802 3.54 1.66
7 FC off L 0.0543 0.0561 4.08 1.99
8 FC off U 0.0714 0.0737 3.65 0.65
11 Bu L (2) 0.0586 0.0626 2.72 0.35
12 Bu U (2) 0.0704 0.0703 2.84 0.07
13 Bu L (3) 0.0679 0.0598 2.22 0.35
14 Bu U (3) 0.0650 0.0574 2.15 4.15
15 Bu off L 0.0701 0.0651 1.83 0.01
16 Bu off U 0.0669 0.0729 1.52 0.44
19 Or Sa U 0.0468 0.0463 1.68 1.13
20 Or Iz U 0.0504 0.0464 2.76 0.57
21 Commercial 0.0509 0.0421 2.95 0.67
22 3R4F 0.0643 0.0701 1.80 0.74

The number in parentheses indicates tobaccos of the same type but from different sources.

The same table gives the average results for α-tocopherol in the collected TPM from the UV analysis.

Very similar results with those obtained using UV detection were obtained using MS/MS detection for α-tocopherol. A graph showing the correlation between the UV data and the MS/MS data for the smoke levels of α-tocopherol is shown in Figure 8.

Figure 8

Correlation between the results for α-tocopherol in smoke analyzed by UV detection and by mass spectrometry detection, expressed in μg/mg TPM.

As expected, the correlation between the UV and the MS/MS results is very good.

The results for α-tocopherol in smoke show a relatively good correlation with the level of the compound in the tobacco. In Figure 9 the correlation between the level of α-tocopherol in smoke as a function of the level of the compound in tobacco is shown. In the LC/MS smoke analysis, the trace of the transition m/z = 473.4 → 165.1 corresponding to α-tocopheryl acetate shows a very small peak at the retention time of α-tocopheryl acetate. The peak area was below the quantitation limit, and it could not be determined if it belongs indeed to α-tocopheryl acetate, or it is an interference. The formation of even very low traces of α-tocopheryl acetate in cigarette smoke is not likely.

Figure 9

Correlation between the level of α-tocopherol in smoke as a function of the level of the compound in tobacco.

CONCLUSIONS

A HPLC separation using UV detection as well as MS/MS detection has been developed for the analysis of α-tocopherol and α-tocopheryl acetate. The method has been applied for the quantitation of these compounds in a number of tobaccos, as well as in the TPM from cigarettes made with the same tobaccos. Depending on tobacco type, the levels of α-tocopherol varied between about 200 μg/g up to about 900 μg/g (“dry weight basis”). For ISO type smoking, the levels of α-tocopherol varied in TPM between about 2 μg/mg up to slightly above 4 μg/mg. α-Tocopheryl acetate, which was associated with EVALI and reported in certain counterfeit products, was not detected in tobacco or in tobacco smoke.

Figure 1

Chromatogram of standard Level 5 (6.16 μg/mL α-tocopherol and 6.03 μg/mL α-tocopheryl acetate).
Chromatogram of standard Level 5 (6.16 μg/mL α-tocopherol and 6.03 μg/mL α-tocopheryl acetate).

Figure 2

Extracted ion chromatograms for the compounds in standard Level 5 (6.16 μg/mL α-tocopherol and 6.03 μg/mL α-tocopheryl acetate).
Extracted ion chromatograms for the compounds in standard Level 5 (6.16 μg/mL α-tocopherol and 6.03 μg/mL α-tocopheryl acetate).

Figure 3

Calibration curve for α-tocopherol with UV detection.
Calibration curve for α-tocopherol with UV detection.

Figure 4

Calibration curve for α-tocopheryl acetate with UV detection.
Calibration curve for α-tocopheryl acetate with UV detection.

Figure 5

Calibration curve for α-tocopherol with MS/MS detection.
Calibration curve for α-tocopherol with MS/MS detection.

Figure 6

Calibration curve for α-tocopheryl acetate with MS/MS detection.
Calibration curve for α-tocopheryl acetate with MS/MS detection.

Figure 7

Correlation between the results for α-tocopherol analysis by UV detection and by mass spectrometry detection, expressed in μg/g tobacco.
Correlation between the results for α-tocopherol analysis by UV detection and by mass spectrometry detection, expressed in μg/g tobacco.

Figure 8

Correlation between the results for α-tocopherol in smoke analyzed by UV detection and by mass spectrometry detection, expressed in μg/mg TPM.
Correlation between the results for α-tocopherol in smoke analyzed by UV detection and by mass spectrometry detection, expressed in μg/mg TPM.

Figure 9

Correlation between the level of α-tocopherol in smoke as a function of the level of the compound in tobacco.
Correlation between the level of α-tocopherol in smoke as a function of the level of the compound in tobacco.

Parameters for the MS/MS detection.

Compound Ion for Q1 Ion for Q3 Time (ms) CE3 (V)
α-Tocopherol 431.4 165.1 200 38.0
α-Tocopheryl acetate 473.4 165.1 200 52.0
Uvitex-OB (I.S.) 431.5 415.3 200 49.0

j.cttr-2020-0007.tab.011

Declustering potential DE = 150 V,
Entrance potential = 13 V,
Collision gas (N2) CG = 6 mL/min,
Curtain gas CUR = 10 mL/min,
Ion spray voltage IS = 4000 V,
Temperature TE = 600 °C,
Ion source gas 1 GS1 = 35 mL/min,
Ion source gas 2 GS2 = 30 mL/min.

The list of standards in μg/mL(the addition of 10 μL I.S. slightly changes the final concentrations from the values in the stock solution).

Compound Standard in μg/mL

Level 1 Level 2 Level 3 Level 4 Level 5 Level 6 Level 7 Level 8 Level 9 Level 10
α-Tocopherol 98.63 49.31 24.66 12.33 6.16 3.08 1.54 0.77 0.39 0.19
α-Tocopherol acetate 96.47 48.24 24.12 12.06 6.03 3.01 1.51 0.75 0.38 0.19

Percent recovery of α-tocopherol in a second extraction from total in the sample.

Experiment First extraction (μg/g) Second extraction (μg/g) % in second extraction
1 749.16 15.70 2.05
2 812.54 18.66 2.24
3 768.32 14.57 1.86
4 808.30 16.14 1.96

The values for LOQ for α-tocopherol and α-tocopheryl acetate in μg/mL standard solution and per g of sample.

Compound LOQ solution (μg/mL) LOQ sample (μg/g)
α-Tocopherol 0.19 1.9
α-Tocopheryl acetate 0.19 1.9

The TPM in g generated from 5 cigarettes smoked under ISO type conditions and the average results for α-tocopherol in μg/mg in the collected TPM as obtained by the analysis with UV detection.

Sample No. Sample acronym a TPM, Repetition 1 (g) TPM, Repetition 2 (g) Average α-tocopherol in TPM (μg/mg) RSD (%)
3 FC L (2) 0.0668 0.0639 3.35 0.38
4 FC U (2) 0.0794 0.0816 3.98 1.11
5 FC L (3) 0.0534 0.0559 4.17 3.60
6 FC U (3) 0.0818 0.0802 3.54 1.66
7 FC off L 0.0543 0.0561 4.08 1.99
8 FC off U 0.0714 0.0737 3.65 0.65
11 Bu L (2) 0.0586 0.0626 2.72 0.35
12 Bu U (2) 0.0704 0.0703 2.84 0.07
13 Bu L (3) 0.0679 0.0598 2.22 0.35
14 Bu U (3) 0.0650 0.0574 2.15 4.15
15 Bu off L 0.0701 0.0651 1.83 0.01
16 Bu off U 0.0669 0.0729 1.52 0.44
19 Or Sa U 0.0468 0.0463 1.68 1.13
20 Or Iz U 0.0504 0.0464 2.76 0.57
21 Commercial 0.0509 0.0421 2.95 0.67
22 3R4F 0.0643 0.0701 1.80 0.74

Timetable for the gradient HPLC separation.

Run time (min) Solvent A % Solvent B % Detection
0.0 85.0 15.0 On
15.0 85.0 15.0 On
15.5 40.0 60.0 On
16.0 40.0 60.0 Off
18.5 40.0 60.0 Off
19.0 85.0 15.0 Off
25.0 85.0 15.0 Off

Average α-tocopherol levels in μg/g tobacco as measured using the UV detection.

Sample No. Sample acronym a (μg/g) “as is” (μg/g) “dry base” RSD (%)
1 FC L (1) 731.18 778.26 0.27
2 FC U (1) 857.27 914.80 1.92
3 FC L (2) 760.38 812.39 2.09
4 FC U (2) 823.72 884.26 1.92
5 FC L (3) 778.92 840.15 1.93
6 FC U (3) 823.06 881.57 2.53
7 FC off L 746.77 807.48 2.86
8 FC off U 764.48 833.36 2.65
9 Bu L (1) 231.93 246.68 0.24
10 Bu U (1) 336.85 361.00 0.81
11 Bu L (2) 396.24 423.70 0.54
12 Bu U (2) 599.52 641.43 2.80
13 Bu L (3) 267.59 289.24 2.54
14 Bu U (3) 284.40 308.09 0.56
15 Bu off L 327.57 354.40 0.92
16 Bu off U 255.28 276.32 0.37
17 Or (1) 296.70 316.40 0.65
18 Or (2) 267.31 283.97 0.08
19 Or Sa U 181.74 197.00 1.31
20 Or Iz U 427.01 456.35 0.37
21 Commercial 510.19 546.97 0.53
22 3R4F 404.30 432.03 0.31

Coefficients for the calibration curves Y = a X + b and of R2 used in UV quantitation.

Compound a b R2
α-Tocopherol 0.022401 −0.05633 1.00
α-Tocopheryl acetate 0.022655 −0.05204 1.00

Coefficients for the calibration curves Y = a X + b and of R2 used in MS/MS quantitation.

Compound a b R2
α-Tocopherol 34.2270 −1.00506 0.9997
α-Tocopheryl acetate 10.7472 −1.39160 0.9997

List of tobaccos evaluated in this study, the moisture in % and the indication if cigarettes were available.

No. Sample acronym a Description Moisture (%) Cigarettes available
1 FC L (1) Common blend of lower stalk flue-cured 6.44 No
2 FC U (1) Common blend of upper stalk flue-cured 6.71 No
3 FC L (2) Eastern NC belt, lower stalk (lug) flue-cured 6.84 Yes
4 FC U (2) Eastern NC belt, upper stalk (leaf & some tips) flue-cured 7.35 Yes
5 FC L (3) South Carolina belt, lower stalk (lug) flue-cured 7.86 Yes
6 FC U (3) South Carolina belt, upper stalk (leaf & some tips) flue-cured 7.11 Yes
7 FC off L Brazil, lower stalk (lugs & primings) flue-cured 8.13 Yes
8 FC off U Brazil, upper stalk (leaf & tips) flue-cured 9.01 Yes
9 Bu L (1) Common blend of lower stalk Burley 6.36 No
10 Bu U (1) Common blend of upper stalk Burley 7.17 No
11 Bu L (2) Kentucky & Tennessee, lower stalk (flyings & cutters) Burley 6.93 Yes
12 Bu U (2) Kentucky & Tennessee, upper stalk (leaf) Burley 6.99 Yes
13 Bu L (3) North Carolina & Virginia, lower stalk (flyings & cutters) Burley 8.09 Yes
14 Bu U (3) North Carolina & Virginia, upper stalk (leaf) Burley 8.33 Yes
15 Bu off L Malawi, lower stalk (flyings & rcutters) Burley 8.19 Yes
16 Bu off U Malawi, upper stalk (leaf) Burley 8.24 Yes
17 Or (1) Common blend of Oriental 6.64 No
18 Or (2) Common blend of Oriental 6.23 No
19 Or Sa U Turkey, good quality middle to upper stalk, Samsun Oriental 8.40 Yes
20 Or Iz U Turkey, good quality middle to upper stalk, Izmir Oriental 6.87 Yes
21 Commercial Tobacco blend 7.21 Yes
22 3R4F Tobacco blend 6.86 Yes

Riemenschneider, R.W., R.M. Speck, and E.G. Beinhart: Analysis and Fatty Acid Composition of Tobacco-Seed Oils; Oil Soap 22 (1945) 120–122. DOI: 10.1007/BF02635515 RiemenschneiderR.W. SpeckR.M. BeinhartE.G Analysis and Fatty Acid Composition of Tobacco-Seed Oils Oil Soap 22 1945 120 122 10.1007/BF02635515 Otwórz DOISearch in Google Scholar

Rowland, R.L.: Flue-Cured Tobacco. III. Solanachromene and α-Tocopherol; J. Am. Chem. Soc. 80 (1958) 6130–6133. DOI: 10.1021/ja01555a057 RowlandR.L. Flue-Cured Tobacco. III. Solanachromene and α-Tocopherol J. Am. Chem. Soc 80 1958 6130 6133 10.1021/ja01555a057 Otwórz DOISearch in Google Scholar

Rowland, R.L. and J.A. Giles: Flue-Cured Tobacco, V. Polyisoprenoid Compounds; Tob. Sci. 4 (1960) 29–32. RowlandR.L GilesJ.A Flue-Cured Tobacco, V. Polyisoprenoid Compounds Tob. Sci 4 1960 29 32 Search in Google Scholar

Quin, L.D.: Chemical Studies of Tobacco and its Smoke; Sel. Chim. 2 (1962) 37–62. QuinL.D. Chemical Studies of Tobacco and its Smoke Sel. Chim 2 1962 37 62 Search in Google Scholar

Steadman, R.L.: The Chemical Composition of Tobacco and Tobacco Smoke; Chem. Rev. 68 (1968) 153–207. DOI: 10.1021/cr60252a002 SteadmanR.L. The Chemical Composition of Tobacco and Tobacco Smoke Chem. Rev 68 1968 153 207 10.1021/cr60252a002 4868017 Otwórz DOISearch in Google Scholar

Huber, G.L.: Physical, Chemical, and Biological Properties of Tobacco, Cigarette Smoke, and Other Tobacco Products; in Tobacco and Smoking Cessation, edited by G.L. Huber, Sem. Resp. Med. 10 (1989) pp 297–332. HuberG.L. Physical, Chemical, and Biological Properties of Tobacco, Cigarette Smoke, and Other Tobacco Products; in Tobacco and Smoking Cessation edited by HuberG.L. Sem. Resp. Med 10 1989 297 332 10.1055/s-2007-1006184 Search in Google Scholar

Dong, J.Z, S.C. Moldoveanu, and J.H. Lauterbach: A Parallel Study Between Leaf Chemistry and Particulate-Phase Smoke Chemistry; Presented at the 47th Tobacco Science Research Conference (TSRC), Program Booklet and Abstracts Vol. 47, Paper 6, 1993, p 27. DongJ.Z MoldoveanuS.C. LauterbachJ.H A Parallel Study Between Leaf Chemistry and Particulate-Phase Smoke Chemistry Presented at the 47th Tobacco Science Research Conference (TSRC), Program Booklet and Abstracts 47 Paper 6 1993 27 Search in Google Scholar

Tso, T.C.: Production, Physiology and Biochemistry of Tobacco Plant; Ideals Inc., Beltsville, MD, USA, 1990. ISBN 10: 1878670018 TsoT.C. Production, Physiology and Biochemistry of Tobacco Plant Ideals Inc. Beltsville, MD, USA 1990 ISBN 10: 1878670018 Search in Google Scholar

Rodgman, A.: The Composition of Cigarette Smoke: Problems with Lists of Tumorigens; Beitr. Tabakforsch. Int. 20 (2003) 403–437. DOI: 10.2478/cttr-2013-0758 RodgmanA. The Composition of Cigarette Smoke: Problems with Lists of Tumorigens Beitr. Tabakforsch. Int 20 2003 403 437 10.2478/cttr-2013-0758 Otwórz DOISearch in Google Scholar

Moldoveanu, S.C., J.W. Wilkins, and W.M. Coleman III: Evaluation of the Retention by Humans of Several Cigarette Smoke Constituents; Presented at the 60th Tobacco Science Research Conference (TSRC), Program Booklet and Abstracts Vol. 60, Paper 58, 2006, p 51. MoldoveanuS.C. WilkinsJ.W. ColemanW.MIII Evaluation of the Retention by Humans of Several Cigarette Smoke Constituents Presented at the 60th Tobacco Science Research Conference (TSRC), Program Booklet and Abstracts 60 Paper 58 2006 51 Search in Google Scholar

Green, C.R., J.N. Schumacher, R.A. Lloyd Jr, and A. Rodgman: Comparisons of the Composition of Tobacco Smoke and the Smokes from Various Tobacco Substitutes; Beitr. Tabakforsch. Int. 22 (2007) 258–289. DOI: 10.2478/cttr-2013-0833 GreenC.R. SchumacherJ.N. LloydR.A.Jr RodgmanA Comparisons of the Composition of Tobacco Smoke and the Smokes from Various Tobacco Substitutes Beitr. Tabakforsch. Int 22 2007 258 289 10.2478/cttr-2013-0833 Otwórz DOISearch in Google Scholar

Moldoveanu, S.C. and F.K. St.Charles: Differences in the Chemical Composition of the Particulate Phase of Inhaled and Exhaled Cigarette Mainstream Smoke; Beitr. Tabakforsch. Int. 22 (2007) 290–302. DOI: 10.2478/cttr-2013-0834 MoldoveanuS.C St.CharlesF.K Differences in the Chemical Composition of the Particulate Phase of Inhaled and Exhaled Cigarette Mainstream Smoke Beitr. Tabakforsch. Int 22 2007 290 302 10.2478/cttr-2013-0834 Otwórz DOISearch in Google Scholar

Schmeltz, I., A. de Paolis, and D. Hoffmann: Phytosterols in Tobacco: Quantitative Analysis and Fate in Tobacco Combustion; Beitr. Tabakforsch. 8 (1975) 211–218. DOI: 10.2478/cttr-2013-0382 SchmeltzI. de PaolisA. HoffmannD Phytosterols in Tobacco: Quantitative Analysis and Fate in Tobacco Combustion Beitr. Tabakforsch 8 1975 211 218 10.2478/cttr-2013-0382 Otwórz DOISearch in Google Scholar

Risner, C.H.: The Determination of α-Tocopherol in Tobacco and Mainstream Tobacco Smoke; Presented at the 50th Tobacco Science Research Conference (TSRC), Program Booklet and Abstracts Vol. 50, Paper 46, 1996, p 47. RisnerC.H. The Determination of α-Tocopherol in Tobacco and Mainstream Tobacco Smoke Presented at the 50th Tobacco Science Research Conference (TSRC), Program Booklet and Abstracts 50 Paper 46 1996 47 Search in Google Scholar

Risner, C.H. and P.R. Nelson: The Determination of α-Tocopherol in Environmental Tobacco Smoke; Presented at the 51st Tobacco Science Research Conference (TSRC), Program Booklet and Abstracts Vol. 51, Paper 48, 1997, p 54. RisnerC.H NelsonP.R The Determination of α-Tocopherol in Environmental Tobacco Smoke Presented at the 51st Tobacco Science Research Conference (TSRC), Program Booklet and Abstracts 51 Paper 48 1997 54 10.1093/chromsci/36.2.809487671 Search in Google Scholar

Lampi, A.-M.: Analysis of Tocopherols and Tocotrienols by HPLC; AOAC Lipid library. Available at: https://lipidlibrary.aocs.org/lipid-analysis/selected-topics-in-the-analysis-of-lipids/analysis-of-tocopherols-and-tocotrienols-by-hplc (accessed July, 2020) LampiA.-M. Analysis of Tocopherols and Tocotrienols by HPLC AOAC Lipid library Available at: https://lipidlibrary.aocs.org/lipid-analysis/selected-topics-in-the-analysis-of-lipids/analysis-of-tocopherols-and-tocotrienols-by-hplc (accessed July, 2020) 10.21748/lipidlibrary.40389 Search in Google Scholar

Eitenmiller, R.R. and J. Lee: Vitamin E: Food Chemistry, Composition, and Analysis; CRC Press, New York, NY, USA, 2004. ISBN: 0203970144, 9780203970140 EitenmillerR.R LeeJ Vitamin E: Food Chemistry, Composition, and Analysis CRC Press New York, NY, USA 2004 ISBN: 0203970144, 9780203970140 10.1201/9780203970140 Search in Google Scholar

Ng, M.H. and C.Y. May: Chromatographic Analysis of Tocopherols and Tocotrienols in Palm Oil; J. Chrom. Sci. 50 (2012) 283–286. DOI: 10.1093/chromsci/bms002 NgM.H MayC.Y Chromatographic Analysis of Tocopherols and Tocotrienols in Palm Oil J. Chrom. Sci 50 2012 283 286 10.1093/chromsci/bms002 Otwórz DOISearch in Google Scholar

Mayne, S.T. and R.S. Parker: HPLC Analysis of Vitamin E by Conversion to α-Tocopheryl Acetate in Samples Containing Canthaxanthin or Other Coeluting Compounds; J. Agric. Food Chem. 36 (1988) 483–485. DOI: 10.1021/jf00081a019 MayneS.T ParkerR.S HPLC Analysis of Vitamin E by Conversion to α-Tocopheryl Acetate in Samples Containing Canthaxanthin or Other Coeluting Compounds J. Agric. Food Chem 36 1988 483 485 10.1021/jf00081a019 Otwórz DOISearch in Google Scholar

Moldoveanu, S.C.: Profiling of Lipids from Fruit and Seed Extracts; in Sea Food, Marine Based Dietary Supplement, Fruit and Seed, edited by Su Chen, Chapter 5, 1–19 Lipidomics, Transworld Research, Kerala, India (2012). ISBN: 978-81-7895-573-5 MoldoveanuS.C. Profiling of Lipids from Fruit and Seed Extracts; in Sea Food, Marine Based Dietary Supplement, Fruit and Seed edited by ChenSu Chapter 5, 1 19 Lipidomics, Transworld Research Kerala, India 2012 ISBN: 978-81-7895-573-5 Search in Google Scholar

Rupérez, F.J., D. Martín, E. Herrera, and C. Barbas: Chromatographic Analyses of Alpha-Tocopherol and Related Compounds in Various Matrices; J. Chromatogr. A 935 (2001) 45–69. DOI: 10.1016/s0021-9673(01)01101-3 RupérezF.J. MartínD. HerreraE. BarbasC Chromatographic Analyses of Alpha-Tocopherol and Related Compounds in Various Matrices J. Chromatogr. A 935 2001 45 69 10.1016/s0021-9673(01)01101-3 Otwórz DOISearch in Google Scholar

Xu, Z.: Analysis of Tocopherols and Tocotrienols; Current Protocols in Food Analytical Chemistry 4 (2002) D1.5.1–D1.5.12. DOI: 10.1002/0471142913.fad0105s04 XuZ. Analysis of Tocopherols and Tocotrienols Current Protocols in Food Analytical Chemistry 4 2002 D1.5.1 D1.5.12 10.1002/0471142913.fad0105s04 Otwórz DOISearch in Google Scholar

Ryynänen, M., A. Lampi, P. Salo-Väänänen, V. Ollilainen, and V. Piironen: A Small-Scale Sample Preparation Method With HPLC Analysis for Determination of Tocopherols and Tocotrienols in Cereals; J. Food Comp. Anal. 17 (2004) 749–765. DOI: 10.1016/j.jfca.2003.09.014 RyynänenM. LampiA. Salo-VäänänenP. OllilainenV. PiironenV A Small-Scale Sample Preparation Method With HPLC Analysis for Determination of Tocopherols and Tocotrienols in Cereals J. Food Comp. Anal 17 2004 749 765 10.1016/j.jfca.2003.09.014 Otwórz DOISearch in Google Scholar

Panfili, G., A. Fratianni, and M. Irano: Normal Phase High-Performance Liquid Chromatography Method for the Determination of Tocopherols and Tocotrienols in Cereals; J. Agric. Food Chem. 51 (2003) 3940–3944. DOI: 10.1021/jf030009v PanfiliG. FratianniA. IranoM Normal Phase High-Performance Liquid Chromatography Method for the Determination of Tocopherols and Tocotrienols in Cereals J. Agric. Food Chem 51 2003 3940 3944 10.1021/jf030009v 12822927 Otwórz DOISearch in Google Scholar

Gómez-Coronado, D.J.M., E. Ibañez, F.J. Rupérez, and C. Barbas: Tocopherol Measurement in Edible Products of Vegetable Origin; J. Chromatogr. A 1054 (2004) 227–233. DOI: 10.1016/j.chroma.2004.08.072 Gómez-CoronadoD.J.M. IbañezE. RupérezF.J. BarbasC Tocopherol Measurement in Edible Products of Vegetable Origin J. Chromatogr. A 1054 2004 227 233 10.1016/j.chroma.2004.08.072 15553148 Otwórz DOISearch in Google Scholar

Kadioglu, Y., F. Demirkaya, and A.K. Demirkaya: Quantitative Determination of Underivatized α-Tocopherol in Cow Milk, Vitamin and Multivitamin Drugs by GC-FID; Chromatographia 70 (2009) 665–670. DOI: 10.1365/s10337-009-1184-y KadiogluY. DemirkayaF. DemirkayaA.K Quantitative Determination of Underivatized α-Tocopherol in Cow Milk, Vitamin and Multivitamin Drugs by GC-FID Chromatographia 70 2009 665 670 10.1365/s10337-009-1184-y Otwórz DOISearch in Google Scholar

Nielsen, M.M. and A. Hansen: Rapid High-Performance Liquid Chromatography Determination of Tocopherols and Tocotrienols in Cereals; Cereal Chem. 85 (2008) 248–251. DOI: 10.1094/CCHEM-85-2-0248 NielsenM.M HansenA Rapid High-Performance Liquid Chromatography Determination of Tocopherols and Tocotrienols in Cereals Cereal Chem 85 2008 248 251 10.1094/CCHEM-85-2-0248 Otwórz DOISearch in Google Scholar

Lanina, S.A., P. Toledo, S. Sampels, A. Kamal-Eldin, and J.A. Jastrebova: Comparison of Reversed-Phase Liquid Chromatography-Mass Spectrometry with Electrospray and Atmospheric Pressure Chemical Ionization for Analysis of Dietary Tocopherols; J. Chromatogr. A 1157 (2007) 159–170. DOI: 10.1016/j.chroma.2007.04.058 LaninaS.A. ToledoP. SampelsS. Kamal-EldinA. JastrebovaJ.A Comparison of Reversed-Phase Liquid Chromatography-Mass Spectrometry with Electrospray and Atmospheric Pressure Chemical Ionization for Analysis of Dietary Tocopherols J. Chromatogr. A 1157 2007 159 170 10.1016/j.chroma.2007.04.058 Otwórz DOISearch in Google Scholar

Bustamante-Rangel, M., M.M. Delgado-Zamarreño, A. Sánchez-Pérez, and R. Carabias-Martínez: Determination of Tocopherols and Tocotrienols in Cereals by Pressurized Liquid Extraction-Liquid Chromatography-Mass Spectrometry; Anal. Chim. Acta 587 (2007) 216–221. DOI: 10.1016/j.aca.2007.01.049 Bustamante-RangelM. Delgado-ZamarreñoM.M. Sánchez-PérezA. Carabias-MartínezR Determination of Tocopherols and Tocotrienols in Cereals by Pressurized Liquid Extraction-Liquid Chromatography-Mass Spectrometry Anal. Chim. Acta 587 2007 216 221 10.1016/j.aca.2007.01.049 Otwórz DOISearch in Google Scholar

Kamal-Eldi, A., S. Görgen, J. Pettersson, and A.M. Lampi: Normal-Phase High-Performance Liquid Chromatography of Tocopherols and Tocotrienols. Comparison of Different Chromatographic Columns; J. Chromatogr. A 881 (2000) 217–227. DOI: 10.1016/s0021-9673(99)01346-1 Kamal-EldiA. GörgenS. PetterssonJ. LampiA.M Normal-Phase High-Performance Liquid Chromatography of Tocopherols and Tocotrienols. Comparison of Different Chromatographic Columns J. Chromatogr. A 881 2000 217 227 10.1016/s0021-9673(99)01346-1 Otwórz DOISearch in Google Scholar

Moltó-Puigmartí, C., A.I. Castellote, and M.C. López-Sabater: Ultra-High-Pressure Liquid Chromatographic Method for the Analysis of Tocopherols in Human Colostrum and Milk; J. Chromatogr. A 1216 (2009) 4388–4394. DOI:10.1016/j.chroma.2009.02.088 Moltó-PuigmartíC. CastelloteA.I. López-SabaterM.C Ultra-High-Pressure Liquid Chromatographic Method for the Analysis of Tocopherols in Human Colostrum and Milk J. Chromatogr. A 1216 2009 4388 4394 10.1016/j.chroma.2009.02.088 19368930 Otwórz DOISearch in Google Scholar

Khan, A., M.I. Khan, Z. Iqbal, Y. Shah, L. Ahmad, and D.G. Watson: An Optimized and Validated RP-HPLC/UV Detection Method for Simultaneous Determination of All-Trans-Retinol (Vitamin A) and Alpha-Tocopherol (Vitamin E) in Human Serum: Comparison of Different Particulate Reversed-Phase HPLC Columns; J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 878 (2010) 2339–2347. DOI: 10.1016/j.jchromb.2010.07.009 KhanA. KhanM.I. IqbalZ. ShahY. AhmadL. WatsonD.G An Optimized and Validated RP-HPLC/UV Detection Method for Simultaneous Determination of All-Trans-Retinol (Vitamin A) and Alpha-Tocopherol (Vitamin E) in Human Serum: Comparison of Different Particulate Reversed-Phase HPLC Columns J. Chromatogr. B Analyt. Technol. Biomed. Life Sci 878 2010 2339 2347 10.1016/j.jchromb.2010.07.009 20696624 Otwórz DOISearch in Google Scholar

Gentili, A. and F. Caretti: Evaluation of a Method Based on Liquid Chromatography-Diode Array Detector-Tandem Mass Spectrometry for a Rapid and Comprehensive Characterization of the Fat-Soluble Vitamin and Carotenoid Profile of Selected Plant Foods; J. Chromatogr. A 1218 (2011) 684–697. DOI: 10.1016/j.chroma.2010.12.001 GentiliA CarettiF Evaluation of a Method Based on Liquid Chromatography-Diode Array Detector-Tandem Mass Spectrometry for a Rapid and Comprehensive Characterization of the Fat-Soluble Vitamin and Carotenoid Profile of Selected Plant Foods J. Chromatogr. A 1218 2011 684 697 10.1016/j.chroma.2010.12.001 21190690 Otwórz DOISearch in Google Scholar

Hryniewicka, M., A. Karpinska, M. Kijewska, M.J. Turkowicz, and J. Karpinska: LC/MS/MS Analysis of α-Tocopherol and Coenzyme Q10 Content in Lyophilized Royal Jelly, Beebread and Drone Homogenate; J. Mass Spectrom. 51 (2016) 1023–1029. DOI: 10.1002/jms.3821. HryniewickaM. KarpinskaA. KijewskaM. TurkowiczM.J. KarpinskaJ LC/MS/MS Analysis of α-Tocopherol and Coenzyme Q10 Content in Lyophilized Royal Jelly, Beebread and Drone Homogenate J. Mass Spectrom 51 2016 1023 1029 10.1002/jms.3821 27459546 Otwórz DOISearch in Google Scholar

Jiang, Q., T. Xu, J. Huang, A.S. Jannasch, B. Cooper, and C. Yang: Analysis of Vitamin E Metabolites Including Carboxychromanols and Sulfated Derivatives Using LC/MS/MS; J. Lipid Res. 56 (2015) 2217–2225. DOI: 10.1194/jlr.d061663 JiangQ. XuT. HuangJ. JannaschA.S. CooperB. YangC Analysis of Vitamin E Metabolites Including Carboxychromanols and Sulfated Derivatives Using LC/MS/MS J. Lipid Res 56 2015 2217 2225 10.1194/jlr.d061663 461740826351363 Otwórz DOISearch in Google Scholar

Zhou, W.: Alpha-Tocopherol Analysis by HPLC; Protocol Exchange Method Article Biochemistry (2011). Available at: https://assets.researchsquare.com/files/nprot-2154/v1/manuscript.pdf (assecced July 2020) DOI: 10.1038/protex.2011.244 ZhouW. Alpha-Tocopherol Analysis by HPLC Protocol Exchange Method Article Biochemistry 2011 Available at: https://assets.researchsquare.com/files/nprot-2154/v1/manuscript.pdf (assecced July 2020) 10.1038/protex.2011.244 Otwórz DOISearch in Google Scholar

Cherian S.V., A.Kumar, and R.M. Estrada-Y-Martin: E-Cigarette or Vaping-Product Associated Lung Injury. A Review; Am. J. Med. 133 (2020) 657–663. DOI: 10.1016/j.amjmed.2020.02.004 CherianS.V. KumarA. Estrada-Y-MartinR.M. E-Cigarette or Vaping-Product Associated Lung Injury. A Review Am. J. Med 133 2020 657 663 10.1016/j.amjmed.2020.02.004 32179055 Otwórz DOISearch in Google Scholar

Lanzarotta A., T.M. Falconer, R. Flurer, and R.A. Wilson: Hydrogen Bonding Between Tetrahydrocannabinol and Vitamin E Acetate in Unvaped, Aerosolized, and Condensed Aerosol e-Liquids; Anal. Chem. 92 (2020) 2374–2378. DOI: 10.1021/acs.analchem.9b05536 LanzarottaA. FalconerT.M. FlurerR. WilsonR.A Hydrogen Bonding Between Tetrahydrocannabinol and Vitamin E Acetate in Unvaped, Aerosolized, and Condensed Aerosol e-Liquids Anal. Chem 92 2020 2374 2378 10.1021/acs.analchem.9b05536 31951379 Otwórz DOISearch in Google Scholar

Cao D.J., K. Aldy, S. Hsu, M. McGetrick, G. Verbeck, I. De Silva, and S.-Y. Feng: Review of Health Consequences of Electronic Cigarettes and the Outbreak of Electronic Cigarette, or Vaping, Product Use-Associated Lung Injury; J. Med. Toxicol. 16 (2020) 295–310. DOI: 10.1007/s13181-020-00772-w CaoD.J. AldyK. HsuS. McGetrickM. VerbeckG. De SilvaI. FengS.-Y Review of Health Consequences of Electronic Cigarettes and the Outbreak of Electronic Cigarette, or Vaping, Product Use-Associated Lung Injury J. Med. Toxicol 16 2020 295 310 10.1007/s13181-020-00772-w 732008932301069 Otwórz DOISearch in Google Scholar

International Organization for Standardization (ISO): ISO 3308:2012 Routine Analytical Cigarette Smoking Machine – Definitions and Standard Conditions; ISO, Geneva, Switzerland, 2012. International Organization for Standardization (ISO) ISO 3308:2012 Routine Analytical Cigarette Smoking Machine – Definitions and Standard Conditions ISO Geneva, Switzerland 2012 Search in Google Scholar

International Organization for Standardization (ISO): ISO 4387:2019 Cigarettes – Determination of Total and Nicotine Free Dry Particulate Matter Using a Routine Analytical Smoking Machine; ISO, Geneva, Switzerland, 2019. International Organization for Standardization (ISO) ISO 4387:2019 Cigarettes – Determination of Total and Nicotine Free Dry Particulate Matter Using a Routine Analytical Smoking Machine ISO Geneva, Switzerland 2019 Search in Google Scholar

Moldoveanu, S.C. and V. David: Selection of the HPLC Method in Chemical Analysis; 1st Edition, Elsevier, Amsterdam, NL, 2016, p.21. ISBN: 9780128037119 MoldoveanuS.C DavidV Selection of the HPLC Method in Chemical Analysis 1st Edition Elsevier Amsterdam, NL 2016 21 ISBN: 9780128037119 Search in Google Scholar

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