Extraction optimization using Box–Behnken design and method validation for ethanol in oral fluid

Abstract

An optimization was proposed for the extraction of ethanol from oral fluid (OF) using the headspace (HS) technique, through experimental design and subsequent development and validation of an analytical method using HS-GC/FID and HS-GC/MS.

Studies on the Thermal Decomposition Course of Nitrogen-Rich Heterocyclic Esters as Potential Drug Candidates and Evaluation of Their Thermal Stability and Properties

“…However, in the case of methyl acetates 4-6, the emission of methanol by the presence the stretching vibrations for the C-H (2809-2954 cm −1 ), the deformation vibrations for the C-H (1330-1345 cm −1 ), and the stretching vibrations for the C-O (998-1054 cm −1 ) on the FTIR spectra is confirmed. In addition, the performed QMS analysis showed the presence of m/z ions formed during ionisation of these alcohols, i.e., ethanol (m/z 31, 45,36) and methanol (m/z 29, 30, 31) [29,30]. This clearly indicates the emission of these alcohols during the oxidative decomposition of the tested compounds at T max1 .…”

“…The m/z ions characteristic of ethanol (compounds 1-3) and methanol (compounds 4-6) are well visible from the QMS spectra. The ionization of ethanol leads to the formation of the m/z ions 31 (CH 2 OH + ), 45 (C 2 H 5 O + ), and 46 (C 2 H 5 OH + ) [29], as shown in Figure 5, while the appearance of the m/z ions 29 (CHO + ), 30 (CH 2 O + ), 31 (CH 3 O + ), and 32 (CH 3 OH + ) confirms the emission of methanol [30] under the heating of compounds 4-6. The FTIR spectra clearly indicate that alcohol with the appropriate structure is the main decomposition product of the tested compounds at T max1 .…”

Multianalytical Method Validation for Qualitative and Quantitative Analysis of Solvents of Abuse in Oral Fluid by HS-GC/MS

“…Headspace was maintained at 85°C with incubation time of 5 min. Experimental conditions of headspace time and temperature were chosen based on previous studies performed by our group [ 25 , 26 ].…”

“…Although blood is the most used matrix to assess the exposure to volatile compounds, the suggestion of using OF as biological matrix to monitor the use of drugs of abuse is a global trend because it presents good correlation to blood level [ 23 , 24 ], and it may be collected through commercial devices [ 24 ]. Quantisal was the device chosen to collect OF samples, for its best collection volume indicator (1 mL) and because it has already been validated by our research group [ 24 , 25 ]. After the method was validated, it was applied in OF samples from 22 volunteers, men and women, who were users of multiple drugs, and participants of the Assistance Program for Users of “Club Drugs,” in partnership with the Psychiatric Service of the Clinics Hospital of Porto Alegre and the Center for Drugs and Alcohol Research (CPAD) of the Federal University of Rio Grande do Sul (UFRGS), Brazil.…”

Detection of ethanol in Brazilian gasoline station attendants

“…Oral uid samples were analyzed by the headspace gas chromatography/mass spectrometry (HS-GC/MS) technique using a previously published validated method. 38 An aliquot of 1 mL of OF sample with buffering solution was transferred to a HS vial, followed by the addition of 50 mL n-propanol 0.2 g dL À1 (internal standard). The HS vials were sealed with PTFE/silicone septa and aluminum screw caps, and were placed into the vial rack of the automatic sampler, operating in the HS mode.…”