Determination of anabolic agents in dietary supplements by liquid chromatography-high-resolution mass spectrometry.

A sensitive method for the identification and quantification of anabolic steroids and clenbuterol at trace levels in dietary supplements by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) in atmospheric pressure ionisation (APCI) mode using a single-stage Orbitrap analyser operating at a resolution power of 100 000 full width at half maximum (FWHM) was developed and validated. A total of 1 g of dietary supplement was added with testosterone-d3 as internal standard, dissolved in methanol, evaporated to dryness, diluted in sodium hydroxide solution and extracted with a mixture of pentane/ethyl ether 9:1. The extract was directly injected into the LC-HRMS system. The method was fully validated. Limits of detection (LODs) obtained for anabolic androgenic steroids (AASs) varied from 1 to 25 ng g(-1) and the limit of quantitation (LOQ) was 50 ng g(-1) for all analytes. The calibration was linear for all compounds in the range from the LOQ to 2000 ng g(-1), with correlation coefficients always higher than 0.99. Accuracy (intended as %E) and repeatability (%CV) were always lower than 15%. Good values of matrix effect and recovery were achieved. The ease of the sample preparation together with a fast run time of only 16 min permitted rapid identification of the analytes. The method was applied to the analysis of 30 dietary supplements in order to check for the presence of anabolic agents not labelled as being present in these supplements. Many AASs were often detected in the same sample: indeed, androstenedione was detected in nine supplements, 5-androsten-3ß-ol-17-one (DHEA) in 12, methandienone in three, stanozolol in one, testosterone in seven and testosterone esters in four of them. A retrospective analysis of suspected compounds not included at the beginning of the method development was also possible by means of the full acquisition spectra obtained with the HRMS technique.

Identification and quantification of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide (THC-COOH-glu) in hair by ultra-performance liquid chromatography tandem mass spectrometry as a potential hair biomarker of cannabis use.

We developed and validated an ultra-high-pressure liquid chromatography-tandem mass spectrometry method to identify and quantify 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide in hair of cannabis consumers. After hair washing with methyl alcohol and diethyl ether and subsequent addition of amiodarone as internal standard hair samples were treated with 500 µl VMA-T M3 buffer reagent for 1 h at 100 °C. After cooling, 10 µl VMA-T M3 extract were injected into chromatographic system. Chromatographic separation was carried out on a reversed phase column using a linear gradient elution with two solvents: 5 mM ammonium formate pH 3.0 (solvent A) and 0.1% formic acid in acetonitrile (solvent B). The flow rate was kept constant at 0.4 ml/min during the analysis. The separated analytes were detected with a triple quadrupole mass spectrometer operated in multiple reaction monitoring mode via positive electrospray ionization. Linear calibration curves were obtained for 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide with correlation coefficients (r(2)) of 0.99 and a limit of quantification of 0.25 pg/mg hair. Analytical recovery was between 79.6% and 100.7% and intra- and inter-assay imprecision and inaccuracy were always lower than 15%. Ultra-high-pressure liquid chromatography-tandem mass spectrometry analysis of 20 different hair samples of cannabis consumers disclosed the presence of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide in the range of 0.5-8.6 pg/mg hair. These data provided a good start to consider 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide as alternative hair biomarker of cannabis consumption.

Liquid chromatography-high resolution mass spectrometry (LC-HRMS) determination of stimulants, anorectic drugs and phosphodiesterase 5 inhibitors (PDE5I) in food supplements.

The paper describes a liquid chromatography/high resolution mass spectrometry LC/HRMS method for the simultaneous identification and quantification of stimulants (ephedrines, caffeine, anorectic drugs such as phentermine, phendimetrazine, phenmetrazine, fenfluramine, benfluorex, mephentermine, fencanfamine, sibutramine) and PDE5I (sildenafil, vardenafil and tadalafil) in food supplements using a benchtop Orbitrap mass spectrometer. The mass detector, with a nominal resolving power of 100,000 (FWHM at m/z 200), operated in full scan mode in ESI positive ionization mode. Analytes were identified by retention times, accurate masses and correspondence of experimental and calculated isotopic patterns. The limits of detection (LOD) obtained varied from 1 to 25 ng g(-1) and limits of quantification (LOQ) were 50 ng g(-1) for all compounds. The method was linear for all the analytes in the ranges from 50 to 2000 ng g(-1), giving correlation coefficients>0.99. Accuracy (intended as %E) and repeatability (% CV) were always lower than 15%. The method was applied to the analysis of 36 dietary supplements, revealing the presence of ephedrine and/or pseudoephedrine in four of them, caffeine in eight of them and sildenafil in four of them. In one case, ephedrine was not reported on the label of the dietary supplement, as well as for caffeine in other two cases. A further confirmation of the analytes identity in positive samples was obtained through in-source fragmentation and comparison of the obtained fragments and their relative abundances with those from certified standards. As the acquisition mode is full scan, it would be also possible to re-process a previously acquired datafile for the investigation of untargeted analytes.

Cannabinoids determination in oral fluid by SPME-GC/MS and UHPLC-MS/MS and its application on suspected drivers.

The confirmation of Δ9-tetrahydrocannabinol (THC) in oral fluid (OF) is an important issue for assessing Driving Under the Influence of Drugs (DUID). The aim of this research was to develop a highly sensitive method with minimal sample pre-treatment suitable for the analysis of small OF volumes (100 µL) for the confirmation of cannabinoids in DUID cases. Two methods were compared for the confirmation of THC in residual OF samples, obtained from a preliminary on-site screening with commercial devices. An ultra high performance LC-MS (UHPLC-MS/MS) method and an SPME-GC/MS method were hence developed. 100 µL of the residual mixture OF/preservative buffer or neat OF was simply added to 10 µL of THC-D3 (1 µg/mL) and submitted to the two different analyses: A - direct injection of 10 µL in UHPLC-MS/MS in positive electrospray ionisation (ESI) mode and B - sampling for 30 min with SPME (100 µm polydimethylsiloxane or PDMS fibre) and direct injection by desorption of the fibre in the GC injection port. The lowest limit of detection (LLOD) of THC was 2 ng/mL in UHPLC-MS/MS and 0.5 ng/mL in SPME-GC/MS. In addition, cannabidiol (CBD) and cannabinol (CBN) could be detected in GC/MS equipment at 2 ng/mL, whilst in UHPLC-MS/MS the LLOD was 20 ng/mL. Both methods were applied to 70 samples coming from roadside tests. By SPME-GC/MS analysis, THC was confirmed in 42 samples, whilst CBD was detected in 21 of them, along with CBN in 14 samples. THC concentrations ranged from traces below the lowest limit of quantification or LLOQ (2 ng/mL) up to 690 ng/mL.

Quantification of fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) in meconium for detection of alcohol abuse during pregnancy: Correlation study between both biomarkers.

This article presents results from 47 meconium samples, which were analyzed for fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) for detection of gestational alcohol consumption. A validated microwave assisted extraction (MAE) method in combination with GC-MS developed in the Institute of Forensic Science (Santiago de Compostela) was used for FAEE and the cumulative concentration of ethyl myristate, ethyl palmitate and ethyl stearate with a cut-off of 600ng/g was applied for interpretation. A simple method for identification and quantification of EtG has been evaluated by ultrasonication followed solid phase extraction (SPE). Successful validation parameters were obtained for both biochemical markers of alcohol intake. FAEE and EtG concentrations in meconium ranged between values lower than LOD and 32,892ng/g or 218ng/g respectively. We have analyzed FAEE and EtG in the same meconium aliquot, enabling comparison of the efficiency of gestational ethanol exposure detection. Certain agreement between the two biomarkers was found as they are both a very specific alcohol markers, making it a useful analysis for confirmation.

UHPLC-MS/MS and UHPLC-HRMS identification of zolpidem and zopiclone main urinary metabolites and method development for their toxicological determination.

Zolpidem and zopiclone (Z-compounds) are non-benzodiazepine hypnotics of new generation that can be used in drug-facilitated sexual assault (DFSA). Their determination in biological fluids, mainly urine, is of primary importance; nevertheless, although they are excreted almost entirely as metabolites, available methods deal mainly with the determination of the unmetabolized drug. This paper describes a method for the determination in urine of Z-compounds and their metabolites by ultra-high-pressure liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS) and UHPLC coupled with high resolution/high accuracy Orbitrap® mass spectrometry (UHPLC-HRMS). The metabolic profile was studied on real samples collected from subjects in therapy with zolpidem or zopiclone; the main urinary metabolites were identified and their MS behaviour studied by MS/MS and HRMS. Two carboxy- and three hydroxy- metabolites, that could be also detected by gas chromatography/mass spectrometry (GC-MS) as trimethylsylyl derivatives, have been identified for zolpidem. Also, at least one dihydroxilated metabolite was detected. As for zopiclone, the two main metabolites detected were N-demethyl and N-oxide zopiclone. For both substances, the unmetabolized compounds were excreted in low amounts in urine. In consideration of these data, a UHPLC-MS/MS method for the determination of Z-compounds and their main metabolites after isotopic dilution with deuterated analogues of zolpidem and zopiclone and direct injection of urine samples was set up. The proposed UHPLC-MS/MS method appears to be practically applicable for the analysis of urine samples in analytical and forensic toxicology cases, as well as in cases of suspected DFSA.

Possible fatal acetaminophen intoxication with atypical clinical presentation.

Acetaminophen or paracetamol, a commonly used over-the-counter analgesic, is known to elicit severe adverse reactions when taken in overdose, chronically at therapeutic dosage or, sporadically, following single assumptions of a therapeutic dose. Damage patterns including liver damage and, rarely, acute tubular necrosis or a fixed drug exanthema. We present a case of fatal acetaminophen toxicity with postmortem blood concentration 78 µg/mL and unusual clinical features, including a visually striking and massive epidermolysis and rhabdomyolysis, disseminated intravascular coagulation and myocardial ischemia. This case is compared with the most similar previous reports in terms of organ damage, clinical presentation, and cause of death. We conclude that a number of severe patterns of adverse effects to acetaminophen are emerging that were previously greatly underestimated, thus questioning the adequacy of the clinical spectrum traditionally associated with acetaminophen intoxication and leading to the need to review this spectrum and the associated diagnostic criteria.

Ultra high performance liquid chromatography-electrospray ionization-tandem mass spectrometry screening method for direct analysis of designer drugs, "spice" and stimulants in oral fluid.

An ultra high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) screening method for the direct analysis in oral fluid (OF) of 24 drugs, including new synthetic cannabinoids and so-called "smart" designer drugs, in a single chromatographic run was set up. Benzylpiperazine, methylone, 5,6-methylenedioxy-2-aminoindane (MDAI), fenproporex, 4-fluoroamphetamine (4-FA), 4-methyl-N-ethylcathinone (4-MEC), 4-methylamphetamine (4-MA), methylbenzodioxolylbutanamine (MBDB), mephedrone, methylthioamphetamine (MTA), methylenedioxypyrovalerone (MDPV), mefenorex, nabilone, furfenorex, clobenzorex, JWH-200, AM 694, JWH-250, JWH-073, JWH-018, JWH-019, JWH-122, HU 210 and CP 47497 were determined in a chromatographic run of 9 min only with no sample pre-treatment, after addition of ISs and dilution in mobile phase A. This method is designed to be applied to 250 µL of OF sample, anyway is suitable to be used on smaller volumes (till 100 µL). LODs vary from 1ng/mL to 20 ng/mL. No interfering peaks were observed due to similar analytes, common therapeutic drugs or endogenous compounds. Matrix effect, although present especially for mephedrone, is acceptable, allowing the detection of the compounds at the LODs described. The developed method was applied on 400 real OF samples from on-site tests performed by police officers.

Evaluation of four oral fluid devices (DDS®, Drugtest 5000®, Drugwipe 5+® and RapidSTAT®) for on-site monitoring drugged driving in comparison with UHPLC-MS/MS analysis.

New Italian legislation on driving under the influence of drugs considers oral fluid (OF) as a possible alternative drug testing matrix. On this basis, the present research was carried out to evaluate the applicability of four commercial on-site OF drug screening devices, namely DDS(®), Drugtest 5000(®), Drugwipe 5+(®) and RapidSTAT(®), in a real operative context. Preliminarily trained police officers tested randomly stopped drivers with two different kits side-by-side during roadside patrols. A central laboratory confirmed on-site kits' results by UHPLC-MS/MS analysis of the saliva specimen remaining after the screening analysis. 1025 drivers were submitted to the OF tests: 11.6% were positive for cocaine and metabolites, 11.1% for THC, 6% for amphetamines and amphetamine-type designer drugs and 2.3% for ketamine. The sensitivities of the kits were 81% (RapidSTAT(®)), 82% (DDS(®)), 90% (Drugwipe 5+(®)) and 97% (Drugtest 5000(®)) for cocaine and 38% (DDS(®)), 47% (Drugwipe 5+(®)), 72% (RapidSTAT(®)) and 92% (Drugtest 5000(®)) for THC. Drugtest 5000 was the only kit showing an acceptable sensitivity for on-site application. Only Drugtest 5000(®) and RapidSTAT(®) could be evaluated for amphetamines and methamphetamines: Drugtest 5000(®) showed a sensitivity of 100% in the case of amphetamines and 86% for methamphetamines, while RapidSTAT(®) 90% and 76% respectively. Nowadays, ketamine is not included in the target analytes of any on-site devices, but it was systematically included in the UHPLC-MS/MS confirmatory analysis. To ensure adequate reliability, MS confirmation of on-site OF screening tests is anyway always necessary, due to the presence of a significant number of false positive results even when using the commercial kit with the best performance.

A snapshot of workplace drug testing in Italy.

The Italian Decree on Health and Safety at Work (81/08) prescribes mandatory drug tests for jobs which pose safety hazards to others. Workplace drug testing is performed in accordance with the Provision of the Government-Regions Conference, 2008. The aim of our survey was to examine the prevalence of drug use and the main drug findings in a sample of Italian workers performing hazardous jobs. From September 2009 to February 2011, 551 urine samples were collected in 42 Italian companies. Sample collection was carried out at the workplace by qualified laboratory personnel sent from the Institute of Occupational Medicine of the Catholic University (UCSC) of Rome. The workers to be tested were informed the day before, as the law requires. The samples were checked for adulteration, coded, and sent immediately to the laboratory of the UCSC Forensic Toxicology Analytical Unit. The screening test was an immunoassay. The positive samples proceeded to the confirmatory analysis with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The urine samples were analyzed for cannabis, opiates, amphetamines, methamphetamines, cocaine, methadone, and MDMA. Out of 16 samples .9% screened positive; only 4 of them (0.7%) were confirmed with the LC-MS/MS. Confirmed results included cocaine (2 samples), cannabis (1 sample), both cocaine and cannabis (1 sample). The prevalence of positive samples was lower than expected. Such finding cannot be explained by a low reliability of the testing procedure but could be due to test scheduling. More positive cases might be found performing short-notice random testing.

Subarachnoid hemorrhage during sexual activity after sildenafil intake: an accidental association?

We report and describe an autopsy case of a man dead for rupture of cerebral artery aneurysm with subsequent subarachnoid hemorrhage after sexual intercourse. Toxicologic analysis demonstrated that he had consumed sildenafil (Viagra). Although subarachnoid hemorrhage has been reported to be associated with sexual intercourse, it is not among the known adverse effects of sildenafil. However, sildenafil has been found to interact with vascular physiology via multiple mechanisms and in most of the vascular districts of the human body. This case provides an example of a very rare association between this drug and a fatal pathologic event and deserves to be added to the existing clinical knowledge about sildenafil and the pathophysiology of the events involved. This knowledge may be helpful in orienting further investigation into the mechanisms of action of sildenafil and their clinical implications.

UHPLC-ESI-MS/MS method for direct analysis of drugs of abuse in oral fluid for DUID assessment.

An ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry method for the direct analysis in oral fluid (OF) of several abused drugs and metabolites in a single chromatographic run was set up and validated. Amphetamine, methamphetamine, morphine, O-6-monoacetylmorphine, cocaine, codeine, methylenedioxymethamphetamine (MDMA), methylenedioxyethylamphetamine, methylenedioxyamphetamine, methadone, benzoylecgonine (BEG), Δ9-tetrahydrocannabinol (THC), ketamine, and cocaethylene were determined in a single chromatographic run with no sample pretreatment, after addition of the respective deuterated internal standards. The method was designed to perform a confirmation analysis on the residual OF samples after the preliminary on-site screening test, and it was applied on preservative buffers from different devices (Mavand Rapidstat, Concateno DDS, and Greiner Bio-One) or on neat OF samples. The method was suitable to be applied to the small amounts of sample available for the confirmatory analysis after the preliminary on-site screening or on undiluted OF samples. Limits of detection varied from 5 (morphine) to 0.2 ng/mL (methamphetamine, MDMA, BEG, and cocaethylene). The method was linear for all the substances involved, giving quadratic correlation coefficients of >0.99 in all the different preservative buffers checked. In addition, repeatability and accuracy were satisfactory for the majority of the substances, except for a few cases. The developed method was subsequently applied to 466 residual samples from on-site screening performed by police officers. Of these samples, 74 showed the presence of cocaine and metabolites; THC was detected in 49 samples. Two samples showed codeine and morphine while MDMA was detected in 11 samples and ketamine in four samples.

Determination of ketamine and amphetamines in hair by LC/MS/MS.

A liquid chromatography-tandem mass spectrometry method was developed for the determination of ketamine (with its metabolite norketamine) and some amphetamines (amphetamine, methamphetamine, methylenedioxyamphetamine, and 3,4-methylenedioxymethamphetamine). This method was developed to determine these compounds in hair and is able to simultaneously quantify all of them in human hair. Hair samples (20 mg) were washed and pulverized, and an extraction with formic acid (0.01%) and ultrasonication for 4 h was used. Deuterated analogs of the analytes were used as internal standards for quantification. Linearity from 0.5 to 25 ng/mg was obtained for both ketamine (and norketamine) and amphetamines with correlation coefficients exceeding 0.99. The limit of detection and the limit of quantification obtained were 0.1 and 0.5 ng/mg, respectively, for ketamine and amphetamines. A total of 25 hair samples from known drug abusers (relating to designer drug consumption or consumption of amphetamines) were examined by this validated method. The results show that the proposed method is suitable for testing these drugs in a single sample of hair. In addition, it is simpler and faster than analysis by conventional methods such as gas chromatography-mass spectrometry, which usually require a more laborious extraction procedure and, in most of cases, an additional derivatization process.

Ethanol contamination leads to Fatty acid ethyl esters in hair samples.

The diagnosis of alcoholism is a topical subject of discussion; in fact, many studies have been published on the determination of biochemical markers useful to this target. Fatty acid ethyl esters (FAEE) are minor metabolites of ethanol, and their usefulness has been demonstrated by their detection in hair using a headspace solid-phase microextraction-gas chromatographic-mass spectrometric technique. Environmental contamination in the analysis of drugs of abuse is a well-known focus of discussion between scientists. In the same way, interference from the surroundings could be hypothesized in FAEE detection. To assess the influence of ethanol contamination, an in vitro experiment was performed, leaving hair in an atmosphere saturated with ethanol vapors for 15 days. The spontaneous production of FAEE was demonstrated by analyzing hair day by day. In fact, we observed a constant increase of ethyl myristate, palmitate, and stearate that reached very high concentrations at the end of the investigation. Although the experiment was managed in a stressed way and could not represent real life, its purpose was to focus the attention of researchers on the problem of hair contamination that can occur, for example, with ethanol-containing cosmetics. Therefore, care in interpretation must be taken into account, especially with such a volatile molecule.

The reliability of fatty acid ethyl esters (FAEE) as biological markers for the diagnosis of alcohol abuse.

The search for biochemical markers for the objective diagnosis of alcoholism has been a topic of research because of the important clinical and forensic implications. In the last few years, two minor ethanol metabolites (ethylglucuronide and fatty acid ethyl esters) have been mainly investigated in hair samples for their ability to be incorporated into this biological matrix. The aim of this study was to experience the detection of fatty acid ethyl esters (FAEE) in the hair of alcoholics, social drinkers, and teetotallers in order to give a contribution to the existing literature. Hair samples from 12 alcoholics, 10 social drinkers, and 10 teetotallers were analyzed by gas chromatography-mass spectrometry technique after headspace solid-phase microextraction with deuterated internal standards. A slight overlap in FAEE concentration between the three groups was found, probably because of external contamination. This observation suggests particular attention to the interpretation of the results. Nevertheless, the results obtained show the usefulness of these biochemical markers in the diagnosis of alcoholism.

Determination of airborne polycyclic aromatic hydrocarbons at an airport by gas chromatography-mass spectrometry and evaluation of occupational exposure.

The aim of this study was to determine airborne polycyclic aromatic hydrocarbons (PAHs) and biphenyl at an airport by gas chromatography-mass spectrometry and to evaluate occupational exposure by environmental monitoring. A total of 12 samplings were carried out in three areas: (1) a handling area where baggage was unloaded manually from vehicles onto conveyor belts (n=5); (2) the runway with plane and motor vehicle traffic (n=5) and (3) a departure lounge (n=2). PAHs levels were in most cases low. The higher levels found refer to naphthalene (130-13,050 ng/m3) and to its methyl-substitutes 2-methylnaphthalene (64-28,500 ng/m3) and 1-methylnaphthalene (24-35,300 ng/m3), and biphenyl (24-1610 ng/m3). A method was used to quantify twenty-four airborne PAHs, and biphenyl, and to detect a variety of other chemical compounds by means of the deconvolution program AMDIS. After sampling air on quartz filter and PUF and XAD-2 sorbents; extraction with dichloromethane, and concentration and purification on silica cartridges, analyses were carried out by gas chromatography-ion trap mass spectrometry. We used 20 deuterated PAHs to quantify both the 24 native PAHs and biphenyl. The native substances had been subdivided into small groups and in this way, their volatility was adequately reflected by the D-PAH present in each group. The limit of detection was 0.1 ng/m3 for all the PAHs, and a linear range of at least about three-fold the maximum level studied (naphthalene) was obtained both for D-PAHs and the native PAHs. A good recovery pattern was obtained for D-PAHs on quartz filters, PUF and XAD-2.

Acute flurazepam intoxication: a case report.

A fatality due to ingestion of flurazepam is reported. Flurazepam is a benzodiazepine, a widely prescribed hypnotic drug for use in sleep disorders. There are only few documented reports of the disposition of flurazepam in deaths due to overdose. A 68-year-old woman was found deceased at home with no evidence of trauma or asphyxia. Toxicologic analyses were performed and drug levels measured by means of gas chromatography coupled to mass spectrometry. The flurazepam concentration in each specimen was as follows: heart blood 2.8 microg/mL, bile 323 microg/mL, and urine 172 microg/mL. Presence of flurazepam into gastric content was observed too. Based on the autopsy findings, patient history, and toxicologic results, the cause of death was determined to be acute intoxication of flurazepam and the manner, suicide.

Liquid chromatography/mass spectrometry analysis of exhaled leukotriene B4 in asthmatic children.

BACKGROUND: The role of leukotriene (LT) B4, a potent inflammatory mediator, in atopic asthmatic and atopic nonasthmatic children is largely unknown. The lack of a gold standard technique for measuring LTB4 in exhaled breath condensate (EBC) has hampered its quantitative assessment in this biological fluid. We sought to measure LTB4 in EBC in atopic asthmatic children and atopic nonasthmatic children. Exhaled nitric oxide (NO) was measured as an independent marker of airway inflammation. METHODS: Fifteen healthy children, 20 atopic nonasthmatic children, 25 steroid-naïve atopic asthmatic children, and 22 atopic asthmatic children receiving inhaled corticosteroids were studied. The study design was of cross-sectional type. Exhaled LTB4 concentrations were measured using liquid chromatography/mass spectrometry-mass spectrometry (LC/MS/MS) with a triple quadrupole mass spectrometer. Exhaled NO was measured by chemiluminescence with a single breath on-line method. LTB4 values were expressed as the total amount (in pg) of eicosanoid expired in the 15-minute breath test. Kruskal-Wallis test was used to compare groups. RESULTS: Compared with healthy children [87.5 (82.5-102.5) pg, median and interquartile range], exhaled LTB4 was increased in steroid-naïve atopic asthmatic [255.1 (175.0-314.7) pg, p < 0.001], but not in atopic nonasthmatic children [96.5 (87.3-102.5) pg, p = 0.59)]. Asthmatic children who were receiving inhaled corticosteroids had lower concentrations of exhaled LTB4 than steroid-naïve asthmatics [125.0 (25.0-245.0) pg vs 255.1 (175.0-314.7) pg, p < 0.01, respectively]. Exhaled NO was higher in atopic nonasthmatic children [16.2 (13.5-22.4) ppb, p < 0.05] and, to a greater extent, in atopic steroid-naïve asthmatic children [37.0 (31.7-57.6) ppb, p < 0.001] than in healthy children [8.3 (6.1-9.9) ppb]. Compared with steroid-naïve asthmatic children, exhaled NO levels were reduced in asthmatic children who were receiving inhaled corticosteroids [15.9 (11.5-31.7) ppb, p < 0.01]. CONCLUSION: In contrast to exhaled NO concentrations, exhaled LTB4 values are selectively elevated in steroid-naïve atopic asthmatic children, but not in atopic nonasthmatic children. Although placebo control studies are warranted, inhaled corticosteroids seem to reduce exhaled LTB4 in asthmatic children. LC/MS/MS analysis of exhaled LTB4 might provide a non-invasive, sensitive, and quantitative method for airway inflammation assessment in asthmatic children.

Ion trap liquid chromatography/tandem mass spectrometry analysis of leukotriene B4 in exhaled breath condensate.

The objective of this study is the measurement of leukotriene B7 (LTB4), a potent inflammatory mediator, in exhaled breath condensate by using liquid chromatography/mass spectrometry (LC/MS and LC/MS/MS). Condensation of exhaled breath is a non-invasive method to collect airway secretions. Deuterated (d4)-LTB4 was used as internal standard. The MS and MS/MS behavior of LTB4 and LTB4-d4 was studied by electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in both positive and negative ion polarity mode. Preliminary results show that monitoring negative ions in ESI mode has the best sensitivity for both LTB4 and LTB4-d4. Therefore, negative ESI was chosen, and the [M-H]- ions at m/z 335 and 339 were selected for quantification. The lower limit of quantification for LTB4, expressed as the lowest point of the calibration curve, was 100 pg/mL. Using this technique, we measured LTB4 in exhaled breath condensate in two healthy subjects, four asthmatic patients on anti-inflammatory treatment, and four asthmatic patients who were not on anti-inflammatory drugs. Exhaled LTB4 concentrations were detected only in asthmatic patients who were not on anti-inflammatory therapy. This method is potentially useful for non-invasive assessment of airway inflammation, but the sensitivity of the technique needs to be improved.