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PubMed2003

Analysis of off-flavors in the aquatic environment by stir bar sorptive extraction-thermal desorption-capillary GC/MS/olfactometry.

The off-flavor compounds 2-methylisoborneol (MIB), geosmin, 2,4,6-trichloroanisole, 2,3,6-trichloroanisole, 2,3,4-trichloroanisole, and 2,4,6-tribromoanisole were analyzed in water samples by stir bar sorptive extraction (SBSE) followed by on-line thermal desorption (TD) capillary GC/MS. Quantification was performed using the MS in the single-ion-monitoring mode (SIM) with 2,4,6-trichloroanisole-D(5 )as internal standard. Quantification limits are 0.1-0.2 ng L(-1) for the haloanisoles, 0.5 ng L(-1) for geosmin, and 1 ng L(-1) for MIB. The relative standard deviations at the quantification limit ranged from 7 to 14.6%. SBSE recovery was evaluated by spiking real water samples and varied from 87 to 117%. More than twenty samples per day can be analyzed by SBSE-TD-capillary GC-MS. The same technique in combination with olfactometry was used to elucidate unknown odorous compounds in water samples.

Anisoles↗

PubMed2000

Effect of irrigation of the nose with isotonic salt solution on adult patients with chronic paranasal sinus disease.

In a prospective, randomized, controlled, double-blind trial we compared the effectiveness of endonasal irrigations with Ems salt solution to that with sodium chloride solution in the treatment of adult patients with chronic paranasal sinus disease. Subjects (n = 40) were randomly allocated to treatment either with isotonic Ems salt solution or with isotonic sodium chloride solution. The treatment consisted of endonasal irrigation twice daily and additional nasal spray as required. Nasal endoscopy, plain radiography of the paranasal sinuses, olfactometry, anterior rhinomanometry, and a saccharin-clearance test were carried out on days 1 and 7. Patients recorded rating scales of general discomfort, nasal airway obstruction, agreeableness of the irrigation, duration of improved nasal resistance after each irrigation, and the amount of additional nasal spray in a diary. Nasal air flow was not improved significantly. Subjective complaints, endonasal endoscopy, and radiography results revealed a significant improvement in both groups (P = 0.0001). In comparison, the two groups were not significantly different in outcome. Endonasal irrigations with salt solutions are effective in the treatment of chronic sinusitis, and a significant difference between Ems salt and sodium chloride was not observed.

Adult↗

PubMed1998

Clinical validation of a new olfactory test.

A new approach to clinical olfactometry is presented using nasal sprays. A special dosage valve was used to standardize an aerosol size to 40 microns. For evaluation a 6 x 6 matrix (substance/olfactory quality) with verbal associative clues was used according to test psychological findings. Validation took place in three steps after determining smell-associated thresholds in preliminary examinations. Recognition of different aromas administered either by spraying into the open mouth from a distance of 5 cm using nasal sprays or sniffing opened bottles was compared in 50 subjectively normosmic subjects. Findings showed that the correspondence between the two procedures was relatively high, with global identification of odorous substances as high as 98.4% in the spray test. The number of substances used was next reduced to those six substances providing the most reproducible results in an investigation with 56 normosmic and 55 hyposmic subjects. Verbal associative clues were also tested. In a last step 50 patients with hyposmia of various origin and 110 normosmic subjects were tested, allowing previous results to be reproduced regardless of the cause of hyposmia. The spray test was shown to be easily performed and was suitable as a screening test, with a sensitivity of 88% and a specificity of 100%.

Administration, Intranasal↗

PubMed2006

[About the functional aspect of septorhinoplasty].

INTRODUCTION: Rhinosurgeons emphasize the functional aspect of septorhinoplasty (SRP). So far only a few publications with exact data exist. PATIENTS AND METHODS: Fifty-two patients (33 male symbol; 19 female symbol, average age: 37 years) were examined before and approx. 1 year after SRP. Rhinomanometry, olfactometry, and photographic documentation were carried out. Using a questionnaire they were asked about the functional outcome and about their original personal aims concerning the SRP. RESULTS: All patients suffered from a deviated septum. Regarding the external aspect 38 patients had a crooked nose with or without a hump, 7 patients had a hump without external deviated nose, and 7 patients had a saddle nose or other deformities. If total nasal airflow is considered rhinomanometry showed no significant improvement postoperatively (p=0.115). If only the worse nasal side is considered rhinometry showed a highly significant improvement (p=0.002). In the questionnaire 34 patients (65%) indicated an improvement, 14 patients (27%) no change, and 4 patients a deterioration of the nasal airflow. The final aesthetic outcome was assessed by 39 patients (75%) as an improvement, by 12 patients (23%) as unchanged, and by 1 patient (2%) as worse. There were no significant changes in the olfactory function. Asked about their personal aims 29 patients (56%) wished first of all an improvement of nasal airflow, 5 patients (10%) a good aesthetic result, and 18 patients (34%) both aspects. CONCLUSIONS: The results show that use of the term "functional" SRP is justified. In the majority of cases a simultaneously existing functional-plastic problem is solved. Our results support the importance of rhinomanometry as an objective parameter in the perioperative diagnostic battery of nasal obstruction.

Adult↗

PubMed1988

Effects of intrabulbar injections of 6-hydroxydopamine on ethyl acetate odor detection in castrate and non-castrate male rats.

The function of norepinephrine-containing neurons which project to the olfactory bulb is poorly understood. Although there has been suggestion that norepinephrine (NE) may modulate general olfactory sensitivity by attenuating the inhibitory feedback of granule cells upon mitral and tufted cells, behavioral indices of olfactory sensitivity have not been measured in animals with depletions of bulbar NE. The present experiment used computerized olfactometry and signal detection methodology to assess the odor detection performance of castrate and non-castrate male rats to a range of perithreshold concentrations of ethyl acetate following 6-hydroxydopamine (6-OHDA) depletion of bulbar NE. Such depletion had no significant influence on odor detection performance at any of the odorant concentrations examined in either castrate or non-castrate animals, as indexed by the non-parametric sensitivity measure SI. This observation implies that general olfactory sensitivity is unaltered by major depletion of intrabulbar NE, but does not preclude the possibility that NE modulates sensitivity to select odorants or odorant mixtures, or alters detection ability under atypical states of arousal.

Acetates↗

PubMed1991

Influence of adrenalectomy on the odor detection performance of rats.

The influence of adrenalectomy (ADX) on the odor detection performance of male Long-Evans rats was assessed using high-precision olfactometry and a go/no-go operant signal detection task. Nonparametric signal detection measures of sensitivity and responsivity, as well as measures of S+ response latency, the number of aborted trials, and session time, were obtained in daily 250-trial test sessions prior to and after adrenalectomy. Four ADX animals were tested using the odorant pyridine, three using the odorant eugenol, and two using the odorant ethyl acetate. Nine other rats served as sham-operated controls. Neither odor detection nor related nonsensory performance measures were influenced by adrenalectomy or sham-operation procedures. These results imply that adrenalectomy has little or no influence on the odor detection performance of the rat.

Adrenal Cortex↗

PubMed1996

Odor detection performance in hypothyroid and euthyroid rats.

The influence of hypothyroidism on the odor detection ability of male Long-Evans rats was determined using high-precision olfactometry and a go/no-go operant task. Nonparametric signal detection measures of sensitivity and responsitivity, as well as measures of S+ response latency, the number of aborted trials, and session time were obtained in daily 200-trial test sessions prior to, during, and after 50 days of maintenance on 0.1% propylthiouracil (PTU). Similar determinations were made in control animals. Neither odor detection nor associated nonsensory performance measures were influenced by hypothyroidism. These results suggest that PTU-induced hypothyroidism does not affect the odor detection performance of rats.

Animals↗

PubMed1990

Fluprazine hydrochloride: no influence on the odor detection performance of male rats.

Fluprazine hydrochloride (DU 27716) decreases copulatory and offensive attack behaviors of male rats and increases their latency to locate buried food in an open field. Since such behaviors are mediated to some degree by the olfactory system, several investigators have hypothesized that this drug may produce an overall impairment in olfactory sensitivity. To test this hypothesis, the influences of five doses of fluprazine hydrochloride (1.0, 2.5, 5.0, 7.5 and 10.0 mg/kg IP) on the odor detection performance of 12 adult male Long Evans rats was assessed, relative to saline, using high precision olfactometry and a go/no-go operant odor detection task. Treatments were administered every 3rd day in counterbalanced order, with the drug or saline injections occurring 30 minutes before the 260-trial test sessions. No significant influence of fluprazine was observed on odor detection performance, as measured by the nonparametric signal detection sensitivity index SI and the percentage of correct trials. These results indicate that fluprazine does not induce generalized olfactory impairment.

Animals↗

PubMed2005

The use of pine bark and natural zeolite as biofilter media to remove animal rendering process odours.

Studies of odour-control pilot-scale biofilters at a rendering plant were conducted for five years. The biofilters contained different sizes of crushed pine bark or a mixture of zeolite and crushed bark, and treated the exhaust gases from direct-fired meal dryers. The exhaust gases were odorous and contained significant smoke. The odour concentration of the rendering process air ranged between 50,000 and 307,200 OU m(-3). Odour-removal performance measurements of the biofilters were undertaken on five occasions using forced-choice dynamic-dilution olfactometry. Biofilter odour-removal efficiencies of between 80% and 99% were measured at various influent odour concentrations and air loading rates. There was no obvious deterioration in performance of these biofilters between various sampling times in the five year study period. The biofilters also reduced the "offensiveness" of the odour. The fine crushed bark biofilter generally reduced odour concentration more efficiently than the coarse bark biofilter. The additions of zeolite to the bark medium in the biofilter had little effect on the odour-removal performance. An increase in air loading rate produced only a very small decrease in odour-removal performance. The pilot-scale biofilters had smoke removal efficiencies between 71% and 100%. Finely crushed bark removed smoke more effectively than coarsely crushed bark. Drainage from the biofilters contained significant concentrations of pollutants, suggesting that controlled leaching has potential to remove accumulated substances in biofilter media from rendering gas emissions and increase the longevity of a biofilter system.

Abattoirs↗

PubMed2006

The influence of manure composition on emissions of odour and ammonia from finishing pigs fed different concentrations of dietary crude protein.

An investigation was conducted into the influence of manure composition on the odour emission rate (OER) and the emission rate of ammonia (NH(3)), when diets containing 130, 160, 190 and 210gkg(-1) crude protein (CP) were fed to finishing pigs. A group of four boars and four gilts, housed in environmentally sealed pens, were assigned to each diet for a 23-day experimental period which was replicated three times (n=3). Ventilation air from each pen was sampled for NH(3) and odour, by olfactometry, on four days during the trial period. Simultaneous collections of manure were taken from the surface and base of each pit. The pH and the concentrations of dry matter, total Kjeldahl nitrogen (TKN), total ammoniacal nitrogen (TAN) and volatile fatty acids in the manure were measured. Manure composition differed between samples from the surface and base of the pit (P<0.05). Reducing dietary CP concentration decreased the emission of NH(3) (linear, P<0.001). The acetic acid:propionic acid ratio in manure samples was correlated to OER (r=0.79, P<0.001). There was a quadratic relationship between dietary CP concentration and OER (P<0.05). OER decreased between 210gkg(-1) and 160gkg(-1) CP and increased between 160gkg(-1) and 130gkg(-1) CP. In conclusion, reducing dietary crude protein levels could be used effectively to reduce ammonia emissions and OER, although no significant advantage was to be gained in OER from reducing crude protein level below 160gkg(-1).

Ammonia↗

PubMed2004

Volatile organic compounds produced during the aerobic biological processing of municipal solid waste in a pilot plant.

The volatile organic carbon (VOC) and odours emitted during the aerobic biological processing of municipal solid waste (MSW) was studied in a pilot-scale reactor. VOCs were detected by different techniques on solid waste samples and the outlet air stream, before and after a biofilter. Organic compounds (alpha-pinene, beta-myrcene, D-limonene) were also measured in condensate water and leachate from the process. Results showed uniformity in the composition of the air in the solid waste samples, air sampled during the process and condensed water, indicating a matrix-derived origin of these compounds. Leachates, however, contained substances with a quite different molecular structure from the compounds identified in the gaseous fraction. Most of the substances in the gaseous effluent had a hydrocarbon-like structure, mainly terpenoids. The odour produced and detected through olfactometry agreed with GC-MS analyses. This was true above all for terpenes.

Air Pollutants↗

PubMed2004

Identification of 2,3-butanedione (diacetyl) as the compound causing odor events at trace levels in the Llobregat River and Barcelona's treated water (Spain).

A study of organic compounds imparting sweet and buttery odor problems in the Llobregat River (northeast Spain) and in treated water was conducted. Solid-phase microextraction (SPME), gas chromatography-olfactometry, and flavor profile analysis (FPA) were used as analytical methodologies to identify the compound responsible for odor incidents. 2,3-Butanedione (diacetyl) with a concentration range of 0.90-26 microg/l in river water samples entering the water treatment plant was identified as the compound causing the odor events. Flavor profile analysis establishes 0.05 microg/l as its odor threshold concentration (OTC) in water, with an odor recognition concentration of 0.20 microg/l. The analyses were carried out with SPME-GC-MS and parameters affecting SPME extraction such as selection of the fiber (carboxen-polydimethylsiloxane), extraction time (30 min), temperature (60 degrees C), and ionic strength were evaluated. Quality parameters of the optimized method gives good linearity (r2 > 0.999), a limit of detection (0.08 microg/l) similar to the OTC of the compound, and good reproducibility (R.S.D. < 20%). The SPME method was applied to identify the compound causing the odor.

Diacetyl↗

PubMed2006

Chemical characterization of odorous gases at a landfill site by gas chromatography-mass spectrometry.

The composition of odorous gases emitted from a municipal landfill in the city of Izmir, Turkey was investigated using gas chromatography-mass spectrometry, and these data were examined in relation with the odor concentrations. Several volatile organic compounds (VOCs) were identified and quantified at five sampling sites in May and September 2005. Detected VOCs were monoaromatics (0.09-47.42 microg m(-3)), halogenated compounds (0.001-62.91microg m(-3)), aldehydes (0.01-38.55 microg m(-3)), esters (0.01-7.54 microg m(-3)), ketones (0.03-67.60 microg m(-3)), sulfur/nitrogen containing compounds (0.03-5.05 microg m(-3)), and volatile fatty acids (VFAs) (0.05-43.71 microg m(-3)). High levels of aldehydes (propanal up to 38.55 microg m(-3)) and VFAs (formic acid up to 43.71 microg m(-3)) were measured in May. However, VOC concentrations were relatively low in September. The monoaromatics and halogenated compounds were the abundant VOCs in landfill air for the both sampling periods. The benzene-to-toluene (B:T) ratio at the landfill site was significantly lower than urban areas indicating the presence of higher amounts of toluene in landfills compared to traffic exhaust rich urban areas. A statistically significant linear relationship was found between odor concentrations determined by olfactometry and total VOC concentrations. The relationships of odor concentrations with the different groups of chemicals were also examined using a step-wise multiple regression analysis. It was found that the concentrations of aldehydes, ketones, and esters are the best estimators, explaining 96% of the variability in odor concentrations (r2 = 0.96, n = 10, P < 0.01).

Air Pollutants↗

PubMed2005

Assessment of municipal waste compost as a daily cover material for odour control at landfill sites.

The ability of municipal waste compost as a daily cover material to reduce the odorous emissions associated with landfill surfaces was investigated. Trials were carried out using landfill gas, a certified sulphurous gas mix and ambient air as a control. Odorous gas was passed through portable test column filled with compost at different densities (590 kg/m3 and 740 kg/m3). Gas samples were taken from the inlet, outlet and at varying column depths and examined using a combination of sensory analysis (olfactometry) and a novel analytical method (Transportable Selected Ion Flow Tube--TSIFT). Results for the trials using landfill gas showed a 69% odour reduction (OU/m3) through the column for compost with a bulk density of 590 kg/m3, and a reduction of 97% using compost with a bulk density of 740 kg/m3. TSIFT analysis showed an overall decrease in the concentration of terpenes, and sulphurous compounds in the outlet gas from the column for both bulk densities. No significant trend could be identified for the concentrations at different depths within the column. Results show the ability of compost to reduce landfill odours under differing conditions. The inconclusive data provided by TSIFT analysis may be due to the analysis of compounds that are not contributing to odour, and thus highlights the potential for synergetic effects and the importance of sensory measurement when examining odorous emissions.

Odorants↗

PubMed2006

Methods for building an olfactometer with known concentration outcomes.

We provide detailed instructions and part selections for construction of a five-channel air dilution olfactometer capable of generating neat odorants and binary mixtures at a range of known concentrations. At the heart of the olfactometer is an odorant canister that is (1) cheap and readily available, (2) safe and durable, (3) has minimal odor adherence, (4) is easily incorporated into any olfactometer, and critically (5) produces a highly consistent stimulus. By flowing a given carrier gas at a given flowrate through a given odorant in this canister, the same end-vapor is achieved. Flow/concentration outcomes are provided for several odorants routinely used in olfactometry. This tool will enable researchers to generate known concentrations without expensive analytical machinery.

Atmosphere Exposure Chambers↗

PubMed2006

Assessment of olfactory and trigeminal function using chemosensory event-related potentials.

GOALS: To give an overview on the theoretical and practical applications of chemosensory event-related potentials. METHODS: Chemosensory event-related potentials (ERPs) may be elicited by brief and precisely defined odorous stimuli. Based on the principles of air-dilution olfactometry, a stimulator was developed in the late 1970s, which allows stimulation of the olfactory neuroepithelium and the nasal mucosa with no concomitant mechanical stimulation. Chemosensory ERPs were obtained after stimulation of the olfactory nerve (olfactory ERPs) or the trigeminal nerve (somatosensory or trigeminal ERPs). The characteristics of the stimulator for chemosensory research as well as the variables influencing the responses are discussed in this paper. RESULTS: Implementation and normative data from our department are reported with different clinical examples from otorhinolaryngologic clinic. The bulk of the evoked response consists of a large negative component (often referred to as N1), which occurs between 320 and 450 ms after stimulus onset. This component is followed by a large positive component, often referred to as P2, occurring between 530 and 800 ms after stimulus onset. Absence of olfactory ERPs and presence (even with subtle changes) of somatosensory ERPs is a strong indicator of the presence of an olfactory dysfunction. CONCLUSIONS: This review examines and discusses the methods of chemosensory stimulation as well as the electrophysiological correlates elicited by such stimuli. The clinical applications of chemosensory ERPs in neurology and otorhinolaryngology are outlined.

Animals↗

PubMed2006

Chemosensory event-related potentials during sleep--a pilot study.

Aim of the present pilot study was to investigate whether cortically generated chemosensory event-related potentials (ERPs) can be recorded during sleep. Chemosensory function during sleep was assessed in 14 healthy female volunteers. An overnight polysomnography was performed to assess nocturnal sleep and to classify sleep stages. Chemosensory ERPs were recorded using air-dilution olfactometry. H2S (4ppm) was used for olfactory and CO2 (40%, v/v) for trigeminal stimulation. Chemosensory ERPs could be recorded during sleep for both olfactory and trigeminal stimuli in some but not all subjects. Compared to baseline, latencies of olfactory ERPs were longer and amplitudes were larger during light sleep and slow wave sleep (SWS). For trigeminal stimulation N1 latencies were longest during REM sleep. These results indicate that both trigeminal and olfactory ERPs can be recorded during sleep suggesting that chemosensory stimuli are processed on a cortical level during sleep.

Adult↗

PubMed2006

Investigations on multimodal sensory integration: texture, taste, and ortho- and retronasal olfactory stimuli in concert.

Perceptual interactions between odour and oral texture were explored in a study in which a cream odour was presented ortho- or retronasally at well-defined moments whilst milk-like foods with different viscosities, produced by adding a thickener, were present in the mouth. Gaseous (odour) and liquid (texture) pulses were presented using a specially-developed computer-controlled system of air-dilution olfactometry and pumps. Odour pulses, lasting 2 s, were presented either during a 3-s period in which a liquid filled the oral cavity, during a 3-s period in which the liquid was manipulated orally or during the swallowing of the liquid. Subjects rated the intensity of overall flavour, thickness and creaminess. Perceived flavour intensity was reduced with increasing viscosity of the liquid, irrespective of whether or not the odour was presented ortho- or retronasally. The odour stimulus increased the intensities of thickness and creaminess, but only when the odour was presented retronasally that is as if the odour would have originated from the liquid. Furthermore, this enhancement was most pronounced when odours coincided with swallowing, less pronounced when odours coincided with oral manipulation and absent when presented during mouth filling. The results suggest that cross-modal interactions are the rule rather than the exception, provided that multi-modal sensory integration has occurred.

Adult↗