Comparison of molecularly imprinted solid-phase extraction (MISPE) with classical solid-phase extraction (SPE) for the detection of benzodiazepines in post-mortem hair samples

This preliminary study compares the benzodiazepine results for 10 post-mortem scalp hair samples using a classical solid-phase extraction (SPE) and a molecularly imprinted solid-phase extraction (MISPE) system. The hair samples selected for testing were from drug-related deaths where a positive benzodiazepine blood result was obtained. Samples were decontaminated with 0.1% sodium dodecyl sulfate, distilled water and dichloromethane, incubated overnight in methanol/25% aqueous ammonium hydroxide (20:1), extracted by SPE or MISPE and subsequently analysed by liquid chromatography-tandem mass spectrometry (LC-MS-MS). Both extraction methods detected diazepam, nordiazepam, oxazepam, temazepam and nitrazepam in the samples. Diazepam was detected in a greater number of samples using MISPE due to both its lower limit of detection (LOD) and higher extraction recovery as a result of excellent molecular recognition of the template (diazepam) imparted by the imprinting process. The selective recognition of two diazepam analogues, nordiazepam and oxazepam, was demonstrated using MISPE since they were also detected in a greater number of samples. In contrast, another diazepam analogue, temazepam, was detected in a greater number of samples using SPE since the LOD using this extraction was lower than with MISPE. Nitrazepam was detected in one sample using both extraction methods. Overall the MISPE and SPE hair results were in good qualitative agreement. For the samples, where both extraction methods detected nordiazepam, temazepam and oxazepam, the concentrations were always higher for SPE. This is probably due to the MIP procedure producing extracts with fewer matrix interferences than the extracts produced using the classical SPE method. MISPE could be used as a complementary method to classical SPE for the analysis of benzodiazepine positive hair samples collected from chronic users.     

Screening for the presence of drugs in serum and urine using different separation modes of capillary electrophoresis

Capillary electrophoresis (CE) is a modern separation technique that has some distinct advantages for toxicological analysis, such as a high efficiency, fast analysis, flexibility, and complementary separation mechanisms to chromatographic methods. CE can be applied in various modes, which each have a different separation mechanism or selectivity. The most common mode is capillary zone electrophoresis (CZE), in which charged analytes migrate in a buffer under the influence of an electric field. In micellar electrokinetic chromatography (MEKC), micelles are added to the buffer which interact with the analytes. MEKC can also be used for the separation of neutral compounds. In non-aqueous CE (NACE), the aqueous buffer is replaced by a background of electrolytes in organic solvents. A sample that needs to be screened can easily be analyzed subsequently by these CE modes using the same instrumentation.The aim of the study was to develop procedures for the analysis of basic and acidic drugs in serum and urine using CZE, MEKC, and NACE. A test mixture that consisted of six basic and six acidic compounds was used to study the separation behavior of five CE methods. The results showed that three methods (based on CZE, MEKC, and NACE) were suitable for the analysis of basic compounds and three methods (based on CZE and MEKC) for the analysis of acidic compounds.For the extraction of analytes from serum and urine, a solid-phase extraction (SPE) and a liquid-liquid extraction (LLE) method were compared. Both SPE and LLE methods provided clean extracts after extraction of the basic compounds from serum and urine. The extracts of acidic compounds contained more matrix interferences, especially for urine. The SPE method had some advantages compared to LLE, as it lead to cleaner extracts and higher peaks, and as it elutes basic and acidic compounds in one fraction.The potentials and pitfalls of the various methods for screening purposes in analytical toxicology are discussed.     

Quantitative analysis of multiple illicit drugs in preserved oral fluid by solid-phase extraction and liquid chromatography-tandem mass spectrometry

We present a validated method for the simultaneous analysis of basic drugs which comprises a sample clean-up step, using mixed-mode solid-phase extraction (SPE), followed by LC-MS/MS analysis. Deuterated analogues for all of the analytes of interest were used for quantitation. The applied HPLC gradient ensured the elution of all the drugs examined within 14 min and produced chromatographic peaks of acceptable symmetry. Selectivity of the method was achieved by a combination of retention time, and two precursor-product ion transitions for the non-deuterated analogues. Oral fluid was collected with the Intercept, a FDA approved sampling device that is used on a large scale in the US for workplace drug testing. However, this collection system contains some ingredients (stabilizers and preservatives) that can cause substantial interferences, e.g. ion suppression or enhancement during LC-MS/MS analysis, in the absence of suitable sample pre-treatment. The use of the SPE was demonstrated to be highly effective and led to significant decreases in the interferences. Extraction was found to be both reproducible and efficient with recoveries >76% for all of the analytes. Furthermore, the processed samples were demonstrated to be stable for 48 h, except for cocaine and benzoylecgonine, where a slight negative trend was observed, but did not compromise the quantitation. In all cases the method was linear over the range investigated (2-200 microg/L) with an excellent intra-assay and inter-assay precision (coefficients of variation <10% in most cases) for QC samples spiked at a concentration of 4, 12 and 100 microg/L. Limits of quantitation were estimated to be at 2 microg/L with limits of detection ranging from 0.2 to 0.5 microg/L, which meets the requirements of SAMHSA for oral fluid testing in the workplace. The method was subsequently applied to the analysis of Intercept samples collected at the roadside by the police, and to determine MDMA and MDA levels in oral fluid samples from a controlled study.     

Pancuronium bromide (Pavulon) isolation and identification in aged autopsy tissues and fluids

The isolation and detection of pancuronium bromide was developed for aged autopsy samples to identify and confirm this compound in questioned tissue samples. A novel protocol was optimized for the isolation of the target drug in highly decomposed tissues. Solid-phase extraction (SPE) cartridges containing styrene-divinylbenzene were investigated. This polymer retained quaternary drugs and facilitated sequential elution upon washing with commonly available solvents. The semi-purified SPE samples were prescreened by pyrolysis GC-MS. A candidate specimen was then confirmed by microbore high-performance liquid chromatography/electrospray-ionization/mass spectrometry (microHPLC-ESI-MS/MS) with a triple-quadrupole mass spectrometer. The developed procedures provided a qualitative or semiquantitative (at best) basis for the investigation of difficult cases involving overdoses of polar drugs.     

体液中常见滥用药物的系统筛选分析

本文建立了体液中常见滥用药物的筛选分析体系.尿液或血液经固相萃取(SPE)或液提取(LLE)后,直接用GC/NPD分析或经TFA、BSTFA衍生化后用GC/MS分析.方法适用于同时分析甲基苯丙胺、MDMA、度冷丁、去甲度冷丁、曲马多、美沙酮、EDDP、可卡因、苯甲酰芽子碱、可待因、安定、氯丙嗪、吗啡、单乙酰吗啡等十四种常见滥用药物及代谢物.SPE法和LLE法回收率分别为66～102%和50～86%,最低检出限为2-5ng/ml尿.涉毒案件的鉴定应用表明该分析方法简便、快速、可靠.     

Quantitative analysis of multiple illicit drugs in preserved oral fluid by solid-phase extraction and liquid chromatography–tandem mass spectrometry

We present a validated method for the simultaneous analysis of basic drugs which comprises a sample clean-up step, using mixed-mode solid-phase extraction (SPE), followed by LC–MS/MS analysis. Deuterated analogues for all of the analytes of interest were used for quantitation. The applied HPLC gradient ensured the elution of all the drugs examined within 14 min and produced chromatographic peaks of acceptable symmetry. Selectivity of the method was achieved by a combination of retention time, and two precursor-product ion transitions for the non-deuterated analogues. Oral fluid was collected with the Intercept^®, a FDA approved sampling device that is used on a large scale in the US for workplace drug testing. However, this collection system contains some ingredients (stabilizers and preservatives) that can cause substantial interferences, e.g. ion suppression or enhancement during LC–MS/MS analysis, in the absence of suitable sample pre-treatment. The use of the SPE was demonstrated to be highly effective and led to significant decreases in the interferences. Extraction was found to be both reproducible and efficient with recoveries >76% for all of the analytes. Furthermore, the processed samples were demonstrated to be stable for 48 h, except for cocaine and benzoylecgonine, where a slight negative trend was observed, but did not compromise the quantitation. In all cases the method was linear over the range investigated (2–200 μg/L) with an excellent intra-assay and inter-assay precision (coefficients of variation <10% in most cases) for QC samples spiked at a concentration of 4, 12 and 100 μg/L. Limits of quantitation were estimated to be at 2 μg/L with limits of detection ranging from 0.2 to 0.5 μg/L, which meets the requirements of SAMHSA for oral fluid testing in the workplace. The method was subsequently applied to the analysis of Intercept^® samples collected at the roadside by the police, and to determine MDMA and MDA levels in oral fluid samples from a controlled study.     

全血中扎来普隆两种萃取方法的比较

目的建立血样中扎来普隆的液液萃取和固相萃取方法。方法液液萃取方法是在碱性条件下用二氯甲烷提取。固相萃取是采用OasisHLB固相萃取柱提取,萃取液均用GC/NPD检验,并对其进行比较。结果血样中扎来普隆固相萃取平均回收率达89%以上,液液萃取平均回收率为84%,GC/NPD最低检出限为2×10-2μg.mL-1。结论两种方法均能满足实际检案的需求,而固相萃取方法在减少仪器损耗和内源性杂质干扰方面具有较大的优势。     

Solid-phase cation exchange extraction of basic drugs from the urine of racing greyhounds

The extraction of basic drugs from the urine of racing greyhounds has been carried out for many years using solvent extraction. This paper describes an extraction method that utilises a cation exchange column. Fourteen basic drugs were introduced onto the column in their ionised form, washed with organic and aqueous solvents and eluted with basic methanol. Three drugs, cyclizine, procaine and quinine were determined in authentic samples from racing greyhounds. A comparison of the solid-phase method with liquid-liquid extraction showed an increase in the efficiency of extraction and a reduction in both the time and cost incurred. The method requires a minimal volume of sample and solvent, little glassware and is easily automated.     

Compared interest between hair analysis and urinalysis in doping controls. Results for amphetamines, corticosteroids and anabolic steroids in racing cyclists

In France during a famous bicycle race, the newspapers documented the degree in which doping seemed to be supervised in some teams by managers and doctors. Use of anabolic steroids and other substances was officially banned in the mid-seventies by sports authorities. This policy has been enforced through urine testing before competition. It is well known, however, that a latency period is all that is necessary to defeat these tests. Nevertheless, hair analysis could be a promising tool when testing for periods that are not accessible to urinalysis any more. We have developed different sensitive methods for testing hair for amphetamines, anabolic steroids and their esters and corticosteroids. For amphetamines, 50 mg of hair were digested with 1 M NaOH, extracted with ethyl acetate, derivatized with TFA and analyzed by gas chromatography positive chemical-ionization mass spectrometry. For corticosteroids, 50 mg of powdered hair were treated with methanol in an ultrasonic bath and subsequently purified using a C18 solid phase extraction column. Analysis was realized by high performance liquid chromatography coupled to electrospray-ionization tandem mass spectrometry. For anabolic steroids and their esters, 100 mg of powdered hair were treated with methanol in an ultrasonic bath for extraction of esters, then alkaline digested with 1 M NaOH for an optimum recovery of other drugs. The two liquid preparations were subsequently extracted with ethyl acetate, pooled, then finally highly purified using a twin solid phase extraction on aminopropyl and silica cartridges. Residue was derivatized with MSTFA prior to injection. Analysis was conducted by gas chromatography coupled to a triple quadrupole mass spectrometer. Thirty cyclists were sampled and tested both in hair and in urine. Amphetamine was detected 10 times in hair (out of 19 analyses) compared to 6 times in urine (out of 30 analyses). Corticosteroids were detected 5 times in hair (methylprednisolone 1 case, triamcinolone acetonide 3 cases and hydrocortisone acetate 1 case) in hair (out of 12 analyses) compared to 12 times (triamcinolone acetonide 10 cases and betamethasone 2 cases) in urine (out of 30 analyses). Anabolic steroids were detected twice (nandrolone 1 case, and testosterone undecanoate 1 case) in hair (out of 25 analyses) compared to none in urine (out of 30 analyses).     

Development of a harmonised method for the profiling of amphetamines: IV. Optimisation of sample preparation

The suitability of liquid-liquid extraction (LLE) and solid-phase extraction (SPE) for the preparation of impurity extracts intended for gas chromatographic profiling analyses of amphetamine were evaluated. Both techniques were optimised with respect to the extraction of selected target compounds by use of full factorial designs in which the variables affecting the performance were evaluated. Test samples consisted of amphetamine synthesised by the Leuckart reaction, by reductive amination of benzyl methyl ketone and by the nitrostyrene route. The performance of LLE and SPE were comparable in terms of repeatability and recovery of the target compounds. LLE was considered the better choice for the present harmonised amphetamine profiling method due to the lack of information on the long-term stability of SPE columns.     

Solid-phase extraction and analysis of 20 antidepressant drugs in human plasma by LC/MS with SSI method

A simultaneous determination of 20 antidepressant drugs (imipramine, amitriptyline, desipramine, trimipramine, nortriptyline, clomipramine, amoxapine, lofepramine, dosulepin, maprotiline, mianserin, setiptiline, trazodone, fluvoxamine, paroxetine, milnacipran, sulpiride, tandspirone, methylphenidate and melitracen) in human plasma was developed using LC/MS with sonic spray ionization (SSI) method. These drugs showed good separation and sensitivity by LC-MS using an Inertsil C-8 column with methanol:10mM ammonium acetate (pH 5.0):acetonitrile (70:20:10) as mobile phase at 0.10 mL/min at 35 degrees C. Solid-phase extraction of these drugs added to the human plasma was performed with an Oasis HLB cartridge column. Recovery and limit of detection of these drugs were between 69 and 102% and between 0.03 and 0.63 microg/mL, respectively. The present procedure offers an easier and more convenient screening method for antidepressants, and will be useful for forensic toxicology investigations.     

Automated headspace solid-phase microextraction and capillary gas chromatography analysis of ethanol in postmortem specimens

Solid-phase microextraction (SPME) is a relatively new solventless sample preparation technique that allows simultaneous sampling, extraction, pre-concentration, and introduction of analytes from a sample matrix in a single procedure. This methodology has been used for the analysis of several drugs of forensic toxicology interest including volatile compounds. This paper describes a methodology for analysis of ethanol and other volatile compounds using automatic headspace solid-phase microextraction (HS-SPME) and capillary gas chromatography in postmortem specimens. The methodology was initially developed using standard solutions of acetaldehyde, acetone, methanol, and ethanol. Isobutanol was used as internal standard. Postmortem samples of blood, urine, and vitreous humor were obtained during medico-legal autopsies. To date, there are no published paper regarding alcohol analysis in vitreous humor specimens using HS-SPME and limited literature analyzing blood and urine samples. HS-SPME analysis showed that, under optimized conditions, ethanol and isobutanol (internal standard) were well-separated from other volatile compounds such as acetaldehyde, acetone, and methanol considered to be potential interferents in ethanol analysis. The calibration curves for each volatile compound demonstrated good linearity throughout the concentration range from 0.001 to 1.0 g/dl and the detection limit of ethanol in the studied specimens was approximately 0.0001 g/dl.     

Research of the extraction method of morphine from biological fluids

A solid-phase extraction method of morphine from urine and blood has introduced. The effect of 5 SPE columns, 3 eluents and pH on morphine recovery has been investigated systematically. Derivative GC was used as a method of detection. The result showed that the column and the eluent of such as GDX-301, GDX-403 and C18 chloroform:isopropanol (9:1) had good behaviors to extraction of morphine. When GDX-301 was used as a sorbent, the recovery of morphine from urine was above 90% at pH 9, then went down with the increase of pH. While the recovery from blood was growing with the increase of pH, which reached above 90% in strong alkaline. The extraction method is simple, inexpensive, efficient and reproducible, which provides an effective and practical method to extract morphine and similar illicit drugs from biological fluids.     

General unknown screening in hair by liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS)

The retrospective investigation of the exposure to toxic substances by general unknown screening of hair is still a difficult task because of the large number of possible poisons, the low sample amount and the difficult sample matrix. In this study the use of liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) was tested as a promising technique for this purpose. In the optimized procedure, 20mg hair were decontaminated with water and acetone and two times extracted by 18h incubation with 0.5ml of a mixture of methanol/acetonitrile/H(2)O/ammonium formate at 37°C. A mixture of deuterated standards from different drug groups was added for quantification and method control. The united extracts were evaporated to a residue of 0.5ml and 5μl were injected without clean-up for LC-QTOF-MS measurement (instrument Agilent 6530) with positive electrospray ionization and in data dependent acquisition mode. For peak identification the accurate mass data base and spectral library of the authors was used which contains accurate mass CID spectra of more than 2500 and theoretically calculated accurate mass data of more than 7500 toxicologically relevant substances. Validation at the example of 24 illegal drugs, their metabolites and benzodiazepines resulted in limits of detection of 0.003-0.015ng/mg, and limits of quantification of 0.006-0.021ng/mg with good accuracy and intra- and interday reproducibility. The matrix effect by ion suppression/enhancement was 72-107% for basic drugs and 42-75% for benzodiazepines. Yields of the hair extraction above 90% were determined for 59 drugs or metabolites. The method was applied to hair samples from 30 drug fatalities and from 60 death cases with known therapeutic drug intake at life time. Altogether 212 substances were identified with a frequency per drug of 1-40 (mean 4.2) and per case of 2-33 (mean 10.2), between them 35 illegal drug related substances and 154 therapeutic drugs. Comparison with the data known from case histories and from the analysis of blood, urine and gastric content showed only a low agreement, with many unexpected drugs detected and many reported drugs not detected in hair. Basic drugs and metabolites such as opioides, cocaine, amphetamines, several groups of antidepressants, neuroleptics, beta-blockers or the metamizole metabolite noramidopyrine were found with high frequency whereas acidic and several neutral drugs such as cannabinoids, salicylic acid, furosemide, barbiturates, phenprocoumone or cardiac glycosides could not be detected with sufficient sensitivity, mainly because of the low ion yield of positive ESI for these compounds. The advantage of a comprehensive acquisition of all substances is paid by a lower sensitivity in comparison to targeted screening LC-MS/MS procedures. In conclusion, the procedure of sample preparation and LC-QTOF-MS analysis proved to be a robust and sensitive routine method in which the qualitative screening for a wide variety of toxic substances in hair is combined with the quantitative determination of selected illegal drugs.     

Formation of an interfering substance, 3,4-dimethyl-5-phenyl-1,3-oxazolidine, during a pseudoephedrine urinalysis

During fatal aviation accident investigations, biosamples from the victims are submitted to the FAA Civil Aeromedical Institute (CAMI) for drug analysis. In the process of one such analysis by CAMI, an unknown substance was found in a urine sample. Simultaneous screening by thin layer chromatography (TLC) and gas chromatography/FID (GC/FID) suggested the presence of pseudoephedrine. A subsequent routine confirmation analysis of a separate urine aliquot by GC Fourier transform infrared (GC/FTIR) and GC mass spectrometry (GC/MS) indicated that the retention times of the unknown substance matched with those of pseudoephedrine. However, its infrared and mass spectra were different--the -OH and -NH groups were missing, a C-O-C group was present, and the molar mass was 12 atomic mass units (amu) more than that of pseudoephedrine. A subsequent literature search suggested that ephedrine-like amines react with aldehydes to form oxazolidines. Therefore, the 12-amu increase could be accounted for by condensation of pseudoephedrine with formaldehyde. Since this aldehyde is present in various grades of methanol and ethyl acetate, and these solvents were used during the solid-phase extraction, 3,4-dimethyl-5-phenyl-1,3-oxazolidine was synthesized by using (+)-pseudoephedrine HCl and formaldehyde. The analytical findings of the synthesized compound were consistent with those of the unknown interfering substance, confirming that it was the oxazolidine. Aldehyde contaminants in solvents or specimens can transform drugs of interest and may result in misidentification of a compound originally present in specimens. Therefore, chemicals used in analyses should be of the highest available purity, and a multi-analytical approach should be adopted to maintain a high degree of quality assurance.     

Identification of anhydroecgonine ethyl ester in the urine of a drug overdose victim

Toxicological evaluation of postmortem urine collected from a 41-year-old deceased white male detected anhydroecgonine ethyl ester (ethylecgonidine, AEEE), a transesterification product of smoked cocaine co-abused with ethanol. A solid phase extraction (SPE) method was used to extract cocaine, AEEE, and related metabolites from urine. SPE on a 1 mL urine sample from the decedent followed by GC-MS detected AEEE. Other metabolites identified by GC-MS included cocaine, cocaethylene, and anhydroecgonine methyl ester (AEME). To determine whether some or all of the AEEE was artifactually produced in the heated GC injector port, an alternative LC-MS method was developed. LC/MS following SPE found at least 50 ng/mL of AEEE in the extract. The mass fragmentation (MS/MS and MS3) of AEEE detected in the urine was compared to spectra of authentic, synthesized compound. AEEE is a potential additional forensic marker for the co-abuse of smoked cocaine and ethanol.     

Determination of several psychiatric drugs in whole blood using capillary gas-liquid chromatography with nitrogen phosphorus detection: comparison of two solid phase extraction procedures

A simple and reliable gas chromatographic method with nitrogen-phosphorus detection without derivatization was developed for the detection of several psychiatric drugs in whole blood as part of systematic toxicological analyses (STA). Drugs included mirtazapine, chlorpromazine, methotrimeprazine (levomepromazine), clothiapine, olanzapine, clozapine, haloperidol, and thioridazine. All drugs were studied at concentrations of 100-2,000 microg/L, except haloperidol that was studied at concentrations of 400-8,000 microg/L. In order to select the best blood purification procedure and therefore increase the signal to noise ratio we have compared two solid-phase extraction (SPE) columns, Chem Elut and Bond Elut Certify, for their recovery, precision, sensitivity and matrix purification efficiency. Recoveries for these drugs using Chem Elut columns at 500 and 2,000 microg/L (2,000 and 8,000 microg/L for haloperidol) were in the range 21-65%, with intra-assay and inter-assay precisions of less than 17% and 19%, respectively. Limits of detection (LODs) and limits of quantitation (LOQs) for mirtazapine, chlorpromazine, methotrimeprazine, clothiapine, olanzapine, clozapine, and thioridazine ranged from 62 to 161 microg/L and from 205 to 531 microg/L, respectively. LOD and LOQ for haloperidol were 442 and 1,458 microg/L, respectively. Recoveries of these compounds using Bond Elut Certify columns at 500 and 2,000 microg/L (2,000 and 8,000 microg/L for haloperidol) were in the range 44-97%, with intra-assay and inter-assay precisions of less than 7% and 14%, respectively. LODs and LOQs for mirtazapine, chlorpromazine, methotrimeprazine, clothiapine, olanzapine, clozapine, and thioridazine ranged from 37 to 66 microg/L and from 122 to 218 microg/L, respectively. LOD and LOQ for haloperidol were 156 and 515 microg/L, respectively. Linearity was observed in the studied range for all compounds with r(2) values of >0.999. The use of the mixed-mode bonded-silica Bond Elut Certify columns showed advantages comparing with Chem Elut columns for the screening of these psychotropic agents such as higher recoveries, cleaner extracts, better sensitivity, better precision and less solvent consumption and subsequent disposal.     

Solid-phase extraction for profiling of ecstasy tablets

A solid-phase extraction (SPE) procedure has been developed for impurity profiling of illicit tablets containing 3,4-methylenedioxy-N-methyl-amphetamine (MDMA, ecstasy). Following initial comparison of liquid-liquid extraction and solid-phase extraction, SPE was found to be preferable because it afforded higher extraction efficiencies and shorter extraction times. Procedure blank samples were also analyzed to identify constituents of the extracts which did not originate in the ecstasy tablets. The developed procedure was subsequently applied to 12 samples of seized ecstasy tablets and a comparison was made of these samples to determine similarities and obtain inferences with respect to commonality of origin.     

Detection of trace drugs of abuse in baby formula using solid‐phase microextraction direct analysis in real‐time mass spectrometry (SPME‐DART‐MS)

The intentional or unintentional adulteration of baby formula with drugs of abuse is one of the many increasingly complex samples forensic chemists may have to analyze. This sample type presents a challenge because of a complex matrix that can mask the detection of trace drug residues. To enable screening of baby formula for trace levels of drugs, the use of solid‐phase microextraction (SPME) coupled with direct analysis in real‐time mass spectrometry (DART‐MS) was investigated. A suite of five drugs was used as adulterants and spiked into baby formula. Samples were then extracted using SPME fibers which were analyzed by DART‐MS. Development of a proof‐of‐concept method was completed by investigating the effects of the DART gas stream temperature and the linear speed of the sample holder. Optimal values of 350°C and 0.2 mm/s were found. Once the method was established, representative responses and sensitivities for the five drugs were measured and found to be in the range of single ng/mL to hundreds ng/mL. Additional studies found that the presence of the baby formula matrix increased analyte signal (relative to methanolic solutions) by greater than 200%. Comparison of the SPME‐DART‐MS method to a traditional DART‐MS method for trace drug detection found at least a factor of 13 improvement in signal for the drugs investigated. This work demonstrates that SPME‐DART‐MS is a viable technique for the screening of complex matrices, such as baby formula, for trace drug residues and that development of a comprehensive method is warranted.     

Microwave-assisted extraction and differential scanning calorimetry in the chemical identification of sliming agents apprehended in the south region of Brazil

Over the past decades, consume of slimming agents considerably increased in several countries, including Brazil, due to weight-loss and stimulant properties. Since these drugs are controlled to prevent illicit and indiscriminate use, there is a parallel illegal market that uses the Internet and irregular pharmacies in order to distribute these formulations. Slimming agents produced by these illegal sources are known for being manufactured with little or none quality control resulting in uncertain and unknown formulations. For forensic purposes, apprehended pharmaceuticals have to undergo a process of chemical identification that can be difficult due to its complex matrix. In this sense, application of assisted energies in the extraction step such as microwave irradiation can be a promising method to increase the recuperation of the target molecules of the sample. Therefore, the aim of this research was to identify four slimming agents apprehended in Brazil by means of visual inspection, Fourier Transform Infrared Spectroscopy, Differential Scanning Calorimetry and Gas Chromatography – Mass Spectrometry. Moreover, the efficiency of solid-liquid extraction and microwave-assisted extraction was compared. It should be noted that our work was one of the few to use Differential Scanning Calorimetry and the application of microwave irradiation in the analysis of apprehended materials. Results showed that the majority of the samples was counterfeit being composed of one or several adulterants or contaminants. Initially, visual inspection resourcefully screened the slimming agents for possible signs of falsification, however it failed to detect fraudulent products that were very similar to veridical medicines. Sequentially, Fourier Transform Infrared Spectroscopy detected functional groups present in the samples while the presence or absence of the alleged active ingredients were successfully measured with Differential Scanning Calorimetry and, thus, providing a full chemical screening of the apprehended materials. Gas Chromatography- Mass Spectrometry confirmed the presence of adulterants such as caffeine, fluoxetine and phenolphthalein as well as contaminants such as sulfurol in the falsified samples. Finally, comparison of extraction procedures indicated that microwave-assisted extraction increased the recovery of compounds detected in chromatographic analysis to a greater extent than solid-liquid extraction.