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.

Rapid and Sensitive Voltammetric Determination of Aclonifen in Water Samples.

This paper presents the use of square wave voltammetry (SWV) and square wave adsorptive stripping voltammetry (SWAdSV) in conjunction with a cyclic renewable silver amalgam film electrode (Hg(Ag)FE) for the determination of aclonifen in spiked water samples. A reduction peak at -0.65 V versus Ag/AgCl was obtained in the selected buffer (borax buffer with pH 9.2), exhibiting the characteristics of an irreversible reaction. The effect of square wave (SW) frequency, SW amplitude and step potential, as well as accumulation parameters (time and potential) were studied to select the optimal experimental conditions. The calibration curve was linear in the aclonifen concentration range from 1.0×10(-7) to 1.0×10(-6) mol L(-1) and from 1.0×10(-8) to1.0×10(-7) mol L(-1) for SWV and SWAdSV, respectively. The detection and quantification limits were found to be 3.1×10(-8) mol L(-1); 1.0×10(-7) mol L(-1) and 2.9×10(-9) mol L(-1); 9.6×10(-9) mol L-1 for SWV and SWAdSV, respectively. The proposed method was applied successfully in the determination of aclonifen in spiked water samples. The developed procedure can be adequate at least for screening purposes, where positive results should be confirmed by more selective method.

Application of Purpald® for determination of 3-cyclohexene-1-carboxaldehyde and hydroxyisohexyl 3-cyclohexene carboxaldehyde.

A spectrophotometric method for determination of 3-cyclohexene-1-carboxaldehyde and hydroxyisohexyl 3-cyclohexene carboxaldehyde was developed. This procedure is based on the reaction of carbonyl compounds with the selective derivatization reagent Purpald® in alkaline solution. The product of reaction is a colored compound with maximum absorption at 538 nm. The linear relationship is in the range of (2.5-30) × 10-5 mol·l-1 for 3-cyclohexene-1-carboxaldehyde and (2.0-20) × 10-5 mol·l-1 for hydroxyisohexyl 3-cyclohexene carboxaldehyde. The proposed method was successfully used for determination of hydroxyisohexyl 3-cyclohexene carboxaldehyde in a cosmetic product.

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.

Determination of some thiophosphorus insecticides based on coulometric titration with the anodically generated chlorine: a further insight in the reaction mechanism in aqueous medium.

A new method of analytical determination of some thiolo (PS) and thiono (PS) group containing phosphorus insecticides using a coulometric titration with the anodically generated chlorine and biamperometric end-point detection was described. The method worked well for compounds containing one (methamidophos) or two PS bonds (iso-malathion) or one PS bond (fenitrothion) but failed for compounds containing both PS and PS bonds (malathion, dimethoate) or additional sterically hindered CSC bond (fenthion). Based on the found number z of electrons transferred per mol of oxidized compounds, mechanistic pathways for chlorination of PS and PS containing thiophosphorus insecticides with molecular chlorine in aqueous, acidic medium were proposed.