A novel technique for the assessment of volatile organic compounds in the environment and in human breath
International Conference on Health, Healthcare and Eco-civilisation Keyworth Centre, Keyworth Street, London South Bank University
London SE1 6NG , 5-6 Sept 2015
Endogenous volatile organic compounds (EndoVOCs) are released within the human organism as a result of normal metabolic activity or due to pathological disorders including inflammation and cancer. The VOCs enter the blood stream and are eventually metabolized or excreted via exhalation, skin emission including swetting (garlic) , urine, etc.
Identification and quantification of potential disease biomarkers can be seen as the driving force for the analysis of exhaled breath. Also, diagnosis and therapy control with dynamic assessments of normal physiological function or pharmacodynamics are the ultimate aim.
Exogenous VOCs (ExoVOCs) penetrating the body as a result of environmental exposure can be used to quantify environmental and body burden.. While most people can smell high levels of some Exo VOCs, other VOCs have no odor. Odor does not indicate the level of risk from inhalation of this group of chemicals. There are thousands of different VOCs produced and used in our daily lives. Some common examples include:
- Ethylene glycol
- Methylene chloride
Many products we have in our homes release or “off-gas” Exo VOCs. Some examples of sources of Exo VOCs are building materials, home and personal care products, and regular home duties inlcuding cleaing etz.:
Studies have shown that the level of VOCs indoors is generally two to five times higher than the level of VOC’s outdoors. However, in areas with high pollution (much higher levels have been reported).
The recording of vapour phase spectra for various types of VOCs became a fascinating taskin the late 1990 and beginning of the 2000s mainly because the results obtained were in almost all cases not described or known before. Gas chromatography hyphenated with UV spectrophotometry (GC-UV) is a full scan analytical method, where the compounds eluting from a gas chromatographic column are continuously monitored. The result from a GC-UV analysis is in three dimensions; wavelength (nm), absorbance (AU) and the gas chromatographic retention time (seconds or minutes). By taking the average of absorbance at certain wavelength intervals a chromatogram is obtained. If this interval is broad it represents a non specific detection and if it is narrow it can represent a specific detection for a certain group of compounds. This is similar to the total ion current (TIC) and the single ion monitoring (SIM) in GC-MS or the Gram Smidt (non specific chromatogram) and certain wavelength ranges, characteristic for functional groups in GC-FTIR.
Because of the characteristic UV vapour phase spectra for various classes of compounds it is possible to distinguish compounds even if they are co-eluting. Fig. 1 shows such a case.
Fig. 1 Mixed spectrum of two co-eluting compounds. Still naphthalene and a non aromatic aldehyde can be distinguished.
Even if the separation is insufficient so that two components form one chromatographic peek a slight difference in retention time is often enough to obtain two distinct spectra suitable for identification and classification.
Also, trace amount of compound can be identified as shown in Fig.2. In this case a GC-MS (EI) analysis was unable to find this compound.
Fig 2. Identification of a compound at trace level
Rationale for GC-UV
Exhaled breath (EndoVOCs) contains thousands of volatile organic compounds (VOCs) of which the composition varies depending on status of the individual and the environment. Different metabolic processes within the body produce volatile substances that are released into the blood. When the blood reaches the lungs the products are released into lung tissue and airways. Also, chronic inflammation and/or oxidative stress can result in the excretion of volatile compounds that generate unique VOC patterns. Therefore, measuring the presence of VOCs in exhaled air (breathomics), for clinical screening and monitoring purposes has gained increased interest. Also, the technique may be used to monitor the effects of treatments, for example cancer treatments.
Exogenous VOCs (ExoVOCs) has also recently attracted interest when doing
Land use regression (LUR) modeling as a method for estimating fine-scale distributions of ambient air pollutants to provide exposure assessments for research on health effects. Intraurban distributions of nitrogen dioxide (NO2) and benzene, toluene and m- and p-xylene. As recently reported proximity to industrial point sources and road network intersections were significant predictors for all pollutants. The strong contribution of industrial point sources to VOC distributions suggests that facility emission data should be considered whenever possible.
Microorganisms and volatile organic compounds in airborne dust from damp residences.
Nilsson A, Kihlström E, Lagesson V, Wessén B, Szponar B, Larsson L, Tagesson C.
Indoor Air. 2004 Apr;14(2):74-82.
Airborne dust samples from damp (n = 9) and control (n = 9) residences were analyzed for microorganisms (molds and bacteria), bacterial markers (3-hydroxy fatty acids and muramic acid), and adsorbed volatile organic compounds (VOCs).
The number of mold species was greater in the damp residences than in the controls (23 vs.18) and nine mold species were found only in damp residences., Fig. 1.
Figure. 1 Molds in airborne dust from damp (▮) and control (□) residences. The Y-axis describes number of total molds, colony-forming units, and number of esterase-positive cells per gram dust. Error bars indicate standard deviation
The levels of 3-hydroxy fatty acids and muramic acid correlated better in damp residences than in controls, indicating that damp conditions affect the bacterial flora of airborne dust, Fig. 2 and 3.
Figure 3. Muramic acid (▮) and 3-OH fatty acids (□) in airborne dust from damp and control residences
Identifications made by culture and microscopy of the major molds found, i.e. Aspergillus, Cladosporium, and Penicillum, coincided with the identification of VOCs known to be produced by these species as shown in Table 1.
A number of additional VOCs irritating to the skin, eyes, or respiratory tract were also found.
Table 1. Molds (colony-forming units per gram dust) in airborne dust from damp and control residences
|Damp residences||Control residences|
|1||3 × 106Penicillum spp.||1||4 × 105Penicillum spp.|
|6 × 105Aspergillus versicolor||1 × 105Cladosporium|
|6 × 105Botrytis||9 × 104 Yeast|
|6 × 105Dematiaceous hyphomycetes||4 × 104Botrytis|
|2 × 104Penicillum variabile|
|3 × 105Cladosporium||2 × 104Phoma|
|3 × 105 Yeast||2 × 104Aspergillus fumigatus|
|6 × 104Eurotium||2 × 104Eurotium|
|6 × 104Mucor||2 × 104Mucor|
|8 × 103Aspergillus niger|
|2||1 × 106Penicillum spp.||8 × 103Trichoderma|
|2 × 105Cladosporium|
|2 × 105Mucor||2||5 × 106Penicillum spp.|
|2 × 105Eurotium||4 × 106Cladosporium|
|2 × 105Aspergillus spp.||5 × 105 Yeast|
|1 × 105Botrytis|
|1 × 105 Yeast||3||4 × 107Penicillum spp.|
|1 × 105Scopulariopsis|
|1 × 105Rhizopus||4||9 × 106Penicillum spp.|
|4 × 105Cladosporium|
|3||6 × 107Penicillum spp.|
|3 × 107Sterile mycel||5||4 × 106Penicillum spp.|
|9 × 106Cladosporium||6 × 105Aspergillus ochraceus grp|
|2 × 106Penicillum brevicompactum||5 × 104Penicillum variabile|
|2 × 106Fusarium|
|2 × 106Aspergillus spp.||6||7 × 106Penicillum spp.|
|4 × 106Aspergillus versicolor|
|4||3 × 106Penicillum spp.||4 × 106Penicillum brevicompactum|
|4 × 105Eurotium||4 × 106Penicillum corylophilum|
|3 × 105Cladosporium|
|2 × 105Botrytis||7||5 × 105Aspergillus versicolor|
|4 × 104Mucor||4 × 105Penicillum spp.|
|1 × 105Aspergillus ochraceus grp|
|5||5 × 106Penicillum spp.||7 × 104Rhizopus|
|3 × 105Aspergillus versicolor||3 × 104Cladosporium|
|2 × 105Cladosporium|
|2 × 105Botrytis||8||1 × 105Penicillum spp.|
|6 × 104Aspergillus ochraceus grp||4 × 104Cladosporium|
|4 × 104Chrysosporium|
|6||3 × 105Cladosporium||3 × 104Aspergillus fumigatus|
|5 × 104Eurotium||2 × 104 Yeast|
|5 × 104Penicillum spp.||3 × 103 Black-yeast|
|5 × 103Ulocladium|
|5 × 103Paecilomyces||9||1 × 107Penicillum spp.|
|5 × 103 Yeast|
|5 × 103Dematiaceous hyphomycetes|
|5 × 103Chaetomium|
|5 × 103Acremonium|
|7||2 × 104Paecilomyces|
|1 × 104Penicillum spp.|
|4 × 103Aspergillus spp.|
|2 × 103Cladosporium|
|2 × 103Penicillum variabile|
|2 × 103Aspergillus niger|
|2 × 103Alternaria|
|4 × 102Eurotium|
|8||1 × 105Penicillum spp.|
|6 × 104Cladosporium|
|5 × 103 Yeast|
|5 × 103 Black-Yeast|
|2 × 103Mucor|
|9||6 × 105Penicillum spp.|
|9 × 104Mucor|
|9 × 104Fusarium|
|4 × 104Cladosporium|
|4 × 104 Yeast|
The results from this pilot study illustrate the diversity of microorganisms and VOCs present in the indoor environment and suggest that analysis of airborne dust may help to assess human exposure to microorganisms and chemical compounds.
Analysis of the gas phase of cigarette smoke by gas chromatography coupled with UV-diode array detection.
Hatzinikolaou DG, Lagesson V, Stavridou AJ, Pouli AE, Lagesson-Andrasko L, Stavrides JC.
Anal Chem. 2006 Jul 1;78(13):4509-16.
A gas chromatography method, coupled with diode array photometric spectral detection in the ultraviolet region (167-330 nm), was developed for the analysis of the gas phase of cigarette smoke, Fig. 1
Figure 1 Schematic representation of the UV-diode array detection system.
The method enabled us to identify more than 20 volatiles present in the vapor phase of cigarette smoke. In that way, all major volatile organic compounds (including aldehydes, conjugated dienes, ketones, sulfides, furans, and single-ring aromatics), as well as nitric oxide (NO) and hydrogen sulfide (H(2)S), Fig 2.
Figure 2 Typical 3D chromatogram of cigarette smoke gas phase, with some characteristic identified compounds. 2 mL from the fourth puff (mixture of eight cigarettes) of Kentucky 1R4F cigarette were directly injected into the system. A. The nitric oxide region of the 3D chromatogram.
This method can be analyzed in a straightforward manner through a single chromatographic run of <50-min duration.
The method can easily be applied by the introduction of a small volume of the gas-phase stream into the GC injection loop directly through the smoking apparatus exhaust circuit, thus providing an excellent alternative to available methods, which usually require extraction or concentration steps prior to any chromatographic analysis.
Furthermore, all problems concerning aging of the gas phase are eliminated. Twelve compounds (including NO) were chosen for quantification through the use of appropriate calibration standards.
Comparison of the vapor phase yields of these compounds for the reference cigarette Kentucky 1R4F with already reported data indicates that this method is very reliable as far as accuracy and reproducibility of the results are concerned.
Finally, the proposed methodology was used to compare the concentration of these cigarette smoke gas-phase constituents among individual puffs. Fig 3.
Figure 3 Analysis per individual puff of a major international brand cigarette (12 mg tar, 0.9 mg nicotine). Single-puff data represent the gas-phase mixture of eight cigarettes that were simultaneously lit. MIX data represent the vapor phase mixture from the first to eighth puff obtained from eight cigarettes that were lit sequentially. Values are the means ± SD (Y-error bars) of five independent runs.
Exhaled isoprene and acetone in newborn infants and in children with diabetes mellitus.
Nelson N1, Lagesson V, Nosratabadi AR, Ludvigsson J, Tagesson C.
Pediatr Res. 1998 Sep;44(3):363-7.
A new analytical method gas chromatography combined with UV spectrophotometry was used to measure isoprene and acetone in expired breath collected from four different groups of children: 1) healthy newborn babies, 2) healthy preschool children, 3) healthy school children, and 4) diabetic children in different metabolic states.
Both isoprene and acetone could readily be determined in one single analysis of a 250-mL air sample, Fig.1
Figure,1, Gas chromatography-UV analysis of isoprene and acetone in exhaled breath. The three-dimensional plot shows 1) the UV-spectral wavelength (in nanometers) along the x axis, 2) the absorbance of the two compounds(proportional to concentration) along the y axis, and 3) the retention time (in seconds) of the separated compounds along the z axis.
Newborn babies during the first postnatal week had undetectable or very low levels of isoprene in their expired air irrespective of catabolic or anabolic state.
Breath isoprene increased with age, and healthy school children had higher levels than did healthy preschool children, Fig.2.
Figure. 2. Isoprene levels in exhaled breath of 41 different-aged healthy children (23 preschool and 18 school children). Shown are the results of linear regression analysis of the relation between age and breath isoprene, age being the independent variable.
No significant differences in breath isoprene were found between healthy and diabetic children.
Breath acetone was found to correlate with metabolic state both in newborn babies and in diabetic children, table 1,
Table 1. Acetone and isoprene concentration in exhaled breath from healthy and diabetic children
These findings illustrate the potential use of a new technique for breath analysis in children with metabolic disturbances.
Quantitative determination of volatile organic compounds in indoor dust using gas chromatography-UV spectrometry.
Nilsson A1, Lagesson V, Bornehag CG, Sundell J, Tagesson C.
Environ Int. 2005 Oct;31(8):1141-8.
A novel technique, gas chromatography-UV spectrometry (GC-UV), was used to quantify volatile organic compounds (VOCs) in settled dust from 389 residences in Sweden.
The dust samples were thermally desorbed in an inert atmosphere and evaporated compounds were concentrated by solid phase micro extraction and separated by capillary GC.
Eluting compounds were then detected, identified, and quantified using a diode array UV spectrophotometer.
Altogether, 28 compounds were quantified in each sample; 24 of these were found in more than 50% of the samples.
The compounds found in highest concentrations were saturated aldehydes (C5-C10), furfuryl alcohol, 2,6-di-tert-butyl-4-methylphenol (BHT), 2-furaldehyde, and benzaldehyde. Alkenals were also found, notably 2-butenal (crotonaldehyde), 2-methyl-propenal (methacrolein), hexenal, heptenal, octenal, and nonenal. The concentrations of each of the 28 compounds ranged between two to three orders of magnitude, or even more.
These results demonstrate the presence of a number of VOCs in indoor dust, and provide, for the first time, a quantitative determination of these compounds in a larger number of dust samples from residents.
The findings also illustrate the potential use of GC-UV for analysing volatile compounds in indoor dust, some of which are potential irritants (to the skin, eyes or respiratory system) if present at higher concentrations.
The potential use of GC-UV for improving survey and control of the human exposure to particle-bound irritants and other chemicals is inferred.
Volatile organic compounds analyzed by gas chromatography-deep ultraviolet spectroscopy
Acupuncture and Related Therapies Volume 2, Issue 1, February 2014, Pages 25–28
Exhaled breath contains thousands of volatile organic compounds (VOCs) of which the composition varies depending on status of the individual and the environment. Different metabolic processes within the body produce volatile substances that are released into the blood. When the blood reaches the lungs the products are released into lung tissue and airways.
Also, chronic inflammation and/or oxidative stress can result in the excretion of volatile compounds that generate unique VOC patterns. Therefore, measuring the presence of VOCs in exhaled air (breathomics), for clinical diagnosis and monitoring purposes has gained increased interest over the last years.
This paper describes one methodology based on gas chromatography (GC) and deep ultraviolet (DUV) spectroscopy. Spectra of compounds found in exhaled breath are presented.