Development of sampling method and chromatographic analysis of volatile organic compounds emitted from human skin.

AIM: The studies on volatile organic compounds emitted from skin are an interest for chemists, biologists and physicians due to their role in development of different scientific areas, including medical diagnostics, forensic medicine and the perfume design. This paper presents a proposal of two sampling methods applied to skin odor collection: the first one uses a bag of cellulose film, the second one, using cellulose sachets filled with active carbon. MATERIALS & METHODS: Volatile organic compounds were adsorbed on carbon sorbent, removed via thermal desorption and analyzed using gas chromatograph with mass spectrometer. RESULTS: The first sampling method allowed identification of more compounds (52) comparing to the second one (30). Quantitative analyses for acetone, butanal, pentanal and hexanal were done. CONCLUSION: The skin odor sampling method using a bag of cellulose film, allowed the identification of many more compounds when compared with the method using a sachet filled with active carbon.

Detection of potential chronic kidney disease markers in breath using gas chromatography with mass-spectral detection coupled with thermal desorption method.

The analytical potential of chromatographic breath analysis towards detection of compounds suggested as markers of chronic kidney disease (CKD) was tested. Until now, trimethylamine (TMA) considered as a potential marker of renal disorder was detected mainly in plasma. Detection of TMA in breath was rarely undertaken due to analytical difficulties associated with amines' properties. The results of our investigations confirmed that an application of thermal desorption (TD) and gas chromatography with mass-spectral detection (GC/MS) allows direct detection of TMA in breath. The preliminary studies allowed to determine the breath composition in case of patients suffering from CKD and to compare the obtained results to a control group. Breath samples were collected from 14 patients and 9 healthy volunteers. TMA was detected in all patients suffering from CKD in the range 1.76-38.02ppb, but not in the control group. Acetone and isoprene were present in the exhaled air of all examined persons. The concentration of acetone was in the range of 26.52-329.46ppb in the patient group and 73.11-437.14ppb in the control group. Isoprene was detected in the range 57.17-329.8ppb among CKD patients and 27.99-143.77ppb in healthy volunteers. Additionally aliphatic hydrocarbons and sulfur compounds were determined in breath as compounds which could be essential in case of diseases coexisting with CKD. Apart from TMA and pentane no statistically significant differences were found using our analytical technique. TMA was detected in the breath of all patients with CKD and in none of breath samples in control group. TMA seems to be a promising marker of CKD.

[New opportunities of renal diseases diagnostics using gas chromatography]. / Nowe mozliwosci diagnostyki chorób nerek przy wykorzystaniu chromatografii gazowej.

During the last decade the amount of patients suffering from chronic kidney disease (CKD) has increased. The physicians' efforts are focused on early CKD diagnosis and reduction of the end-stage renal diseases incidence. The breath test seems to be a promising diagnostic device offering early noninvasive diseases detection. The aim of presented study was the determination of breath composition in case of persons suffering from CKD. Breath samples were collected from 14 patients and 7 healthy volunteers. Exhaled air samples were analyzed by gas chromatography equipped with mass spectrometer (GC-MS). Samples were enriched using solid phase microextraction (SPME). Trimethylamine (TMA), mentioned in literature as potential marker of chronic kidney diseases, was detected in case of 11 patients. Among breath components were detected: sulfur compounds: dimethyl sulfide (was detected in exhaled air of patients and control group), carbon disulfide (was detected in case of 4 healthy and in case of all patients) and also potential markers of oxidative stress: propane, butane, pentane, 2-methylpentane, hexane. Acetone and isoprene occurred in exhaled air of all studied persons. The considerable increase of acetone concentration in comparison to control group was observed in case of patients with diagnosed diabetes. The application of gas chromatography with mass spectrometer and appropriate enrichment of samples allows to define the breath profile characteristic for chosen the unit of disease. Typical compounds--biomarkers can be useful for early diagnostics.

Application of GC-MS with a SPME and thermal desorption technique for determination of dimethylamine and trimethylamine in gaseous samples for medical diagnostic purposes.

Biogenic amines are interesting compounds which may be of use for medical diagnosis or therapeutic monitoring. The present paper deals with the problems that occur with concentration determination of dimethylamine (DMA) and trimethylamine (TMA). These occur in the breath of people suffering from renal disease. The measurement of amines present in trace concentrations requires the application of suitable analytical methods during sampling, storage and preconcentration. This is particularly so due to their polar and basic properties. In this paper, the application of solid phase microextraction (SPME) and thermal desorption (TD) with subsequent measurement by GC-MS for the determination of amines is discussed. For DMA, preconcentration by SPME did not give satisfactory results. TMA may be analysed using SPME preconcentration with an LOD of 1.5 ppb. Thermal desorption with Tenax as the adsorbing material allows reliable concentration determination for TMA (LOD = 0.5 ppb) and DMA (LOD = 4.6 ppb). DMA cannot be stored reliably in Tedlar bags and longer storage on Tenax (with subsequent TD) does not give good repeatability of results. For TMA, storage can be done on Tenax or in bags, the best results for the latter being achieved with Flex Foil bags.

Improved pre-concentration and detection methods for volatile sulphur breath constituents.

Suitability of different types of pre-concentration (solid phase microextraction and sorbent trapping) and detection (flame photometric detector (FPD) and mass selective detector (MSD)) for gas chromatographic determination of sulphur-containing compounds (H2S, MeSH, EtSH, DMS, COS and CS2) in breath-gas was assessed in this study. Several factors like influence of humidity, influence of oxygen, or stability of target compounds in extraction vessels (SPME vials and sorbent tubes) were investigated. Despite poor stability of VSCs in SPME vials and matrix effects (unfavorable influence of humidity), SPME was found to be a fast and reliable enrichment method, which coupled with mass selective detector provided satisfactory LODs of target compounds at the ppt level (from 0.15 ppb for CS2 to 2.3 ppb for H2S). Application of sorbent trapping with two-bed sorbent tubes containing Tenax TA and Carboxen 1000 gave excellent LODs (0.03-0.3 ppb for 200 ml sample and MSD). Stability of investigated VSCs in sorbents was found to be very poor (30-40% losses after 2 h). FPD showed satisfactory sensitivity only when it was coupled with sorbent trapping. Breath samples were collected into Tedlar bags in a CO2-controlled manner. Humidity was removed during sampling (permeation dryer--Nafion) to avoid unfavorable water dependent effects during analysis.

Suitability of different polymer bags for storage of volatile sulphur compounds relevant to breath analysis.

Suitability of five polymer sampling containers (Nalophan, transparent Tedlar, black layered Tedlar, Teflon and FlexFoil) for sampling and storage of six relevant to breath analysis volatile sulphur compounds: H(2)S, MeSH, EtSH, COS, DMS and CS(2) was studied using solid phase microextraction (SPME) and gas chromatography coupled with mass spectrometry (GC-MS). Investigations were made with respect to the several factors like: recovery, background, influence of light, ageing effect and matrix effects. Additionally, the optimal reusability conditions were established. Findings suggest analyzing the breath VSCs within 6h after sampling. Flexfoil bags were found to be the best choice for the VSCs storage up to 24h (recovery about 90% with the exception of DMS). For shorter storing times (6-8h) transparent Tedlar is a good alternative for Flexfoil (losses up to 10%).