Fiber spray ionization mass spectrometry in forensic chemistry: A screening of drugs of abuse and direct determination of cocaine in urine

Abstract

Rationale Ambient mass spectrometry techniques are much required in forensic chemistry to evaluate evidence with low analytical interference, high confidence, and accuracy. However, traditional methodologies, such as paper spray ionization, have been shown to present low sensitivity in the analysis of illicit drugs from biological matrices. Methods Fiber spray ionization mass spectrometry (FSI‐MS) was developed using a capillary polypropylene (PP) hollow fiber. Seized samples of drugs, i.e. a tablet, blotter paper, hashish, and cocaine powder, were analyzed. Cocaine was quantified from whole urine by dipping the fiber directly into solution. FSI‐MS was tested for the analysis of a sample of urine obtained from a drug abuse suspect. Results The FSI(+) analysis showed the detection of different types of synthetic drugs in tablet and blotter paper samples, e.g. amphetamine, cathinones, phenethylamines, and opioids, while pure cocaine and different types of coca alkaloids were identified from cocaine powder with good sensitivity and high mass accuracy. The hashish analysis by FSI(−) revealed signals of cannabinoids, cannabinoid acids, and cannabinoid derivatives, detected mainly as [M − H]− ions or chlorine adducts [M + Cl]−. The quantification of cocaine in whole urine showed good sensitivity and precision with limits of detection and quantification of 5.16 and 17.21 ng/mL, respectively, linearity above 0.999, and relative standard deviation below 2.71%. The evaluation of seized sample of urine showed the detection of cocaine with relative ion intensity greater than 36%, as well as the metabolites benzoylecgonine and cocaethylene with a relative intensity of 1.4% and 6%, respectively. Conclusions The developed FSI‐MS method has the potential to be applied to forensic sample evaluation as well as to determine illicit drugs from biological matrices in toxicological analysis. The use of a capillary PP fiber has advantages as an extractor agent and ionizing substrate, and also the feature of it being dipped directly into the sample, thus preserving the integrity of the sample, which makes this a very promising ambient mass spectrometry method and relevant to forensic chemistry.

Structural characterization, spectroscopic studies, and molecular docking studies on metal complexes of new hexadentate cyclic peptide ligand

“…The value of magnetic moment of Fe(III) complex was 5.30 B.M., which equivalent to an octahedral geometry of five unpaired electrons in the Fe(III) ion. [ 60–62 ] Also, the octahedral geometry of the Co(II) complex was confirmed by its magnetic moment (5.08 B.M.). [ 63,64 ] Co(II) complex had three bands in its spectrum at 14,444, 24,845, and 27,920 cm −1 , which referred to the 4 T 1g (F) → 4 T 2g (F) ( v 1 ); 4 T 1g (F) → 4 A 2g (F) ( v 2 ); and 4 T 1g (F) → 4 T 1g (P) ( v 3 ) transitions, predictable for an octahedral structure.…”

Applications of ambient ionization mass spectrometry in 2020: An annual review

“…The technique was able to successfully detect both codeine and methadone in raw urine. Fiber spray ionization (FSI)‐MS has also been applied to the detection of cocaine in urine 72 . FSI utilized a capillary polypropylene hollow fiber, which was dipped directly into the lipid sample.…”

Ambient ionization mass spectrometry applied to new psychoactive substance analysis

“…On the other hand, low-polarity analytes interact less with the cellulosic paper, which favors their elution while improving analyte ionization. Chemical modifications of the paper surface can help improve the efficiency of PSI and increase analyte-specific sensitivity (Damon et al, 2016;Filho et al, 2020;Rossini et al, 2020).…”

“…On the other hand, in the PSI technique, powders are dissolved and spotted onto the substrate, and proteins and salts from blood and urine matrices bind well to the cellulosic paper, which prevents clogging at the spray tip and reduces background noise, allowing for LODs in the low picogram range to be achieved (Kennedy et al, 2018;Ma et al, 2015;Vandergrift et al, 2018). Nevertheless, a few matrix effects using PSI have also been reported and, as previously mentioned, the solvent choice has a greater impact on matrix effects than paper properties (Bills & Manicke, 2020;Bills et al, 2018;Bruno et al, 2017;Filho et al, 2020). As an example, observed up to 48% of interference in the lower limit of quantification (LLOQ) of amfetamine-like compounds in whole blood using PSI-MS; visual inspection revealed that these samples were extremely viscous and full of clots, potentially causing the interference .…”