A microfluidic device for presumptive testing of controlled substances

A simple microfluidic device (MFD) has been developed to perform multiple color and crystal tests for controlled substance analysis. The MFD method uses less sample and reagents and generates less waste than traditional spot plate methods while performing several tests simultaneously. This methodology provides significantly more analytical information for a single sample analysis. The current generation device is the size of a microscope slide with four analytical channels: one for microcrystal tests and three for color tests. The optimized devices were subjected to a rigorous validation study using comparative replicate analyses and several operators. Target analytes were methamphetamine, amphetamine, cocaine, and oxycodone and color test reagents used were the Marquis, Simon, and cobalt thiocyanate. For the crystal tests, platinic chloride was used. The validation study showed the MFD's limits of detection to be in the picogram range. Positive tests results were observed in complex mixtures in which the controlled substance was present at concentrations of 5-10% (w/w). The microcrystal reagents showed greater sensitivity than color test reagents when used in the device. Reagent use and waste generation using the devices was 95% less that that used and generated using the traditional methods. The device performance was also shown to be operator independent.     

Microcrystal analysis of cocaine hydrochloride and added adulterants

The objective of this project was to investigate the trends of changes in the crystal morphology of cocaine in the presence of the common adulterants, caffeine and lidocaine HCl. By performing gold chloride microcrystal tests on samples of cocaine with adulterants at 10, 20, and 50% concentrations, trends in the changes of the crystal morphology can be linked to specific adulterants and concentrations. For cocaine/caffeine mixtures, the trend is elongation of one axis, additional branching, and brown discoloration of the crystals. At 50:50 cocaine/caffeine mixtures, branched spherical crystals and long needles appear. The trends for cocaine/lidocaine mixtures include elongation of one axis with an X-shaped middle axis. The axes continue to grow and branching decreases until at 50%, spherical clusters of needles appear. These results indicate microcrystal analysis can be used as a novel method for presumptively identifying not only cocaine but also the identity and concentration of the adulterant.     

Practical aspects of roadside tests for administrative traffic offences in Germany

In the context of the European project ROSITA, the Institut of Legal Medicine Homburg/Saar has co-operated with the Saarland traffic police in order to assess different roadside drug tests for their functionality and reliability in traffic controls, and for their analytical force of evidence. In 254 cases within the time period from June 1999 to December 1999, police officers performed a (voluntary) roadside drug testing in saliva/sweat, or urine, to confirm or refute their initial suspicion that a driver had used drugs. Whereas in 45 cases the tests gave negative results (which were confirmed by lab urinalysis), in 209 cases the police officers ordered blood samples after a positive outcome of the tests.In 203 of the 209 positive cases, the results could be confirmed by GC/MS analysis. Regarding the prevalence of used drugs, a single consumption was found in 156 cases (113 cannabis, 38 amphetamines/methamphetamines, three opiates, two cocaine), and a consumption of two drugs was found in 44 cases (34 cannabis+amphetamines/methamphetamines, five cannabis+opiates, three cannabis + cocaine, two cocaine+amphetamines/methamphetamines). In three cases, multi-consumption was found.In six cases, the performed tests gave an incorrect prediction to the police officer at the roadside.The roadside tests gave 97.6% correct assistance to the police officers in the right direction (79.9% correct positive predictions and 17.7% correct negative predictions). As a consequence, the performed tests can be seen as a positive and needful tool for the police to get an immediate response to their initial suspicion and to take the right steps concerning a following legal action.     

Results of hair analyses for drugs of abuse and comparison with self-reports and urine tests

Urine as well as head and pubic hair samples from drug abusers were analysed for opiates, cocaine and its metabolites, amphetamines, methadone and cannabinoids. Urine immunoassay results and the results of hair tests by means of gas chromatography-mass spectrometry were compared to the self-reported data of the patients in an interview protocol. With regard to the study group, opiate abuse was claimed from the majority in self-reports (89%), followed by cannabinoids (55%), cocaine (38%), and methadone (32%). Except for opiates the comparison between self-reported drug use and urinalysis at admission showed a low correlation. In contrast to urinalysis, hair tests revealed consumption in more cases. There was also a good agreement between self-reports of patients taking part in an official methadone maintenance program and urine test results concerning methadone. However, hair test results demonstrated that methadone abuse in general was under-reported by people who did not participate in a substitution program. Comparing self-reports and the results of hair analyses drug use was dramatically under-reported, especially cocaine. Cocaine hair tests appeared to be highly sensitive and specific in identifying past cocaine use even in settings of negative urine tests. In contrast to cocaine, hair lacks sensitivity as a detection agent for cannabinoids and a proof of cannabis use by means of hair analysis should include the sensitive detection of the metabolite THC carboxylic acid in the lower picogram range.     

Validity testing of commercial urine cocaine metabolite assays: I. Assay detection times, individual excretion patterns, and kinetics after cocaine administration to humans

A validity study of eight commercial urine assays for detection of cocaine metabolite was performed on clinical specimens collected from human subjects who received single 20-mg intravenous doses of cocaine hydrochloride. The specimens were collected under controlled conditions and analyzed in random order under blind conditions. Benzoylecgonine concentration in each specimen also was determined by gas chromatography/mass spectrometry (GC/MS). Mean times of detection of the last positive specimen (greater than or equal to 300 ng/mL of benzoylecgonine equivalents) after cocaine administration varied among seven of the commercial tests from 16.9 to 52.9 h in the following ascending order: Toxi-Lab less than TDx = EMIT dau = EMIT st less than Abuscreen less than Coat-A-Count = Double Antibody. In contrast, a commercial spot test (KDI Quik Test) which was evaluated for detection of cocaine metabolite produced both false positives and false negatives for benzoylecgonine and was not considered to be a valid test for detection of cocaine metabolite. Half-lives of excretion of benzoylecgonine among four subjects varied from 5.9 to 7.9 h, and overall recovery of benzoylecgonine varied from 15.0 to 34.3% of the administered dose of cocaine.     

Roadside oral fluid testing: comparison of the results of drugwipe 5 and drugwipe benzodiazepines on-site tests with laboratory confirmation results of oral fluid and whole blood

Drugged drivers pose a serious threat to other people in traffic as well as to themselves. Reliable oral fluid screening devices for on-site screening of drugged drivers would be both a useful and convenient means for traffic control. In this study we evaluated the appropriateness of Drugwipe 5 and Drugwipe Benzodiazepines oral fluid on-site tests for roadside drug screening. Drivers suspected of driving under the influence of drugs were screened with the Drugwipe tests. Oral fluid and whole blood samples were collected from the drivers and tested for amphetamine-type stimulant drugs, cannabis, opiates, cocaine and benzodiazepines by immunological methods, GC and GC-MS. The performance evaluations of the tests were made by comparing the results of the Drugwipe tests with laboratory GC-MS confirmation results of oral fluid or whole blood. In addition to the performance evaluations of the Drugwipe tests based on laboratory results, a questionnaire on the practical aspects of the tests was written for the police officers who performed the tests. The aim of the questionnaire was to obtain user comments on the practicality of the tests as well as the advantages and weak points of the tests. The results of the performance evaluations were: for oral fluid (sensitivity; specificity; accuracy) amphetamines (95.5%; 92.9%; 95.3%), cannabis (52.2%; 91.2%; 85.1%), cocaine (50.0%; 99.3%; 98.6%), opiates (100%; 95.8%; 95.9%), benzodiazepines (74.4%; 84.2%; 79.2%) and for whole blood accordingly, amphetamines (97.7%; 86.7%; 95.9%), cannabis (68.3%; 87.9%; 84.9%), cocaine (50.0%; 98.5%; 97.7%), opiates (87.5%; 96.9%; 96.6%) and benzodiazepines (66.7%; 87.0%; 74.4%). Although the Drugwipe 5 successfully detected amphetamine-type stimulant drugs and the police officers were quite pleased with the current features of the Drugwipe tests, improvements must still be made regarding the detection of cannabis and benzodiazepines.     

The indirect detection of bleach (sodium hypochlorite) in beverages as evidence of product tampering

Bleach (sodium hypochlorite) has been identified as the adulterant in a relatively large number of product tamperings that have been investigated by the Forensic Chemistry Center (FCC) of the U.S. Food and Drug Administration. In this work, household bleach was added to 23 different beverages at each of three levels. The impact of sodium hypochlorite on these beverages over a 13-day study period was evaluated using the following techniques: diphenylamine spot test for oxidizing agents, potassium iodide-starch test paper for oxidizing agents, pH, iodometric titration for quantitating hypochlorite, ion chromatography for chloride and chlorate quantitation, automated headspace sampling with gas chromatography-flame ionization detection (GC-FID) for determination of chloroform, and visual and organoleptic observations. This study has shown that hypochlorite is fragile when added to most common beverages and typically breaks down either partially or completely over time. In cases where a beverage is suspected of being adulterated with bleach but tests for hypochlorite are negative, it is still possible to characterize the product to demonstrate that the results are consistent with the addition of bleach. An adulterated product will give a positive test for oxidizing agents using the diphenylamine spot test. It is likely that the pH of the adulterated product will be higher than a control of that product. Ion chromatographic analysis shows elevated chloride and chlorate as compared with a control. And, chloroform may also be detected by GC-FID especially if the beverage that was adulterated contains citric acid.     

The rapid determination of cocaine and other local anesthetics using field tests and chromatography

The application of field tests and chromatography to the detection of cocaine and some other local anesthetics that have been used to adulterate cocaine is described. Initial screening of samples by field tests, followed by concurrent TLC and GC, enables rapid identification of these compounds to be achieved. In particular, the use of flow-programmed GC shortens the time for analysis compared with conventional GC and requires negligible equilibration time between consecutive runs [12]. The method gives reliable quantitative data.     

Simultaneous screening and detection of drugs in small blood samples and bloodstains

A gas chromatography-mass spectrometry (GC-MS) method is described for the screening and detection of morphine, codeine, cocaine, benzoylecgonine, methylecgonine, cocaethylene, delta-9-tetrahydrocannabinol (THC), 11-nor-9-carboxy-THC (THC-COOH), 11-hydroxy-THC (11-OH-THC), amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymetamphetamine (MDMA) and N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB) in small blood samples and bloodstains using solid phase SPE columns and a pipetting robot (Gilson Aspec XL). The detection limits are in the order of 1.62-4.10 ng/50 microl spot (amphetamines), 0.15-0.82 ng/50 microl spot (cannabinoids), 1.67-4.70 ng/50 microl spot (cocaine and derivatives) and 4.53-4.91 ng/50 microl spot (opiates) and the correlation factors are between 0.9957 and 0.9999. The method has proven useful in forensic cases with only small sample volumes or bloodstains.     

Validity testing of commercial urine cocaine metabolite assays: III. Evaluation of an enzyme-linked immunosorbent assay (ELISA) for detection of cocaine and cocaine metabolite

A validity assessment study was performed on the Genetic Diagnostic Enzyme Immunoassay test kit, a new enzyme-linked immunosorbent assay (GDC ELISA) for detection of cocaine and cocaine metabolite in urine. A set of 290 urine specimens, comprised of clinical cocaine urines collected from 5 male subjects who had received single doses of intravenous cocaine, drug-free urines spiked with cocaine, cocaine metabolites, cocaine isomers, and other drugs of abuse, were assayed by GDC ELISA. The results were compared with results by gas chromatography/mass spectrometry (GC/MS) assay for benzoylecgonine. Concordance was high between the GDC ELISA assay and GC/MS and with results reported earlier for other commercial assays. Detection times and specificity of the GDC ELISA antibody were most similar to those of the Abuscreen radioimmunoassay for cocaine metabolite. Overall, the assay produced no false negative or false positive results and appeared to be a reliable screening test for detection of cocaine and benzoylecgonine in human urine.     

Clarifying the complex chemistry of cobalt(II) thiocyanate-based tests for cocaine using single-crystal X-ray diffraction and spectroscopic techniques

Cobalt(II) thiocyanate-based tests are routinely used to screen cocaine products, with the formation of a blue species interpreted as a positive response. An array of other organic bases has been identified as false positives – including well-documented cocaine product adulterant lidocaine and its salt. False positives prompt continued test development, though improvements are hindered by unresolved product structures and reaction pathways. Toward greater clarity, cobalt(II) thiocyanate reactions with cocaine hydrochloride, along with lidocaine and its salt, were investigated using multiple analytical techniques. Reactions involving cocaine hydrochloride yielded glassy, amorphous blue material while reactions of lidocaine hydrochloride monohydrate produced larger, needle-like crystals whose structure was determined via single-crystal X-ray diffraction to be an ion pair (Hlidocaine⁺)₂([Co(SCN)₄]²⁻)·H₂O. While the blue precipitate isolated from reactions involving cocaine hydrochloride was unsuitable for crystallographic structure determination, comparative ultraviolet–visible, attenuated total reflectance infrared, and Raman spectroscopic analysis – along with elemental analysis – supports that this solid is comprised of a comparable ion pair (Hcocaine⁺)₂[Co(SCN)₄]²⁻. Pink crystals isolated from lidocaine reaction vessels were identified as coordination compounds cis-[CoL₂(SCN)₂] and trans-[CoL₂(SCN)₂] where L = lidocaine, while pink crystals from both cocaine hydrochloride and lidocaine hydrochloride monohydrate reaction vessels were the coordination polymer trans-[Co(H₂O)₂(SCN)₂]·H₂O. The results presented herein enable reaction optimization to favor a desired product, whether ion pair or coordination species.     

Determination of opiates and cocaine in hair using automated enzyme immunoassay screening methodologies followed by gas chromatographic-mass spectrometric (GC-MS) confirmation

The objective of this study was to develop a two-step strategy for analysis of opiates and cocaine in hair samples involving an immunological screening procedure followed by confirmation of results using gas chromatography-mass spectrometry (GC-MS). A semi-quantitative automated competitive enzyme-linked immunosorbent assay (ELISA) methodology using Oral Fluid Micro-Plate Enzyme Immunoassays (Orasure Technologies, Inc.) was developed and validated. Applicability was proven by analysis of authentic head hair samples from drug users (n=103) and from opiate associated fatalities (n=21). The optimum cutoff values for the ELISA tests were 0.1 ng cocaine-equivalents/mg hair and 0.05 ng morphine-equivalents/mg hair using a 50 mg hair sample. Both ELISA tests had a sensitivity of 100%, the specificity was 66% for cocaine-equivalents and 42% for morphine-equivalents. The intraassay precision was 11% for the cocaine and 3% for the opiates ELISA, while interassay precision was 12% for the cocaine and 4% for the opiates ELISA test. The actual analyte concentrations in the hair samples were determined using GC-MS and were between 0.04 and 5.20 ng/mg for heroin (HER), between 0.04 and 30.01 ng/mg for 6-monoacetylmorphine (MAM), between 0.03 and 11.87 ng/mg for morphine (MOR), between 0.02 and 1.84 ng/mg for codeine (COD), between 0.02 and 2.48 ng/mg for acetylcodeine (AC), between 0.01 and 21.37 ng/mg for cocaine (COC), between 0.03 and 10.51 ng/mg for benzoylecgonine (BE) and between 0.05 and 1.26 ng/mg for cocaethylene (CE). The automated ELISA tests were proven to be valid screening procedures for the detection of cocaine and opiates in hair as confirmed by GC-MS. Screening methods provide rapid and inexpensive automated pre-test procedures to detect drugs in hair or other matrices. For forensic purposes screening therefore represents an ideal complement to routinely applied GC-MS procedures.     

Optimization and validation of CEDIA drugs of abuse immunoassay tests in serum on Hitachi 912

Due to sensitive limits of detection of chromatographic methods and low limit values regarding the screening of drugs under the terms of impairment in safe driving (§ 24a StVG, Street Traffic Law in Germany), preliminary immunoassay (IA) tests should be able to detect also low concentrations of legal and illegal drugs in serum in forensic cases. False-negatives should be avoided, the rate of false-positive samples should be low due to cost and time. An optimization of IA cutoff values and a validation of the assay is required for each laboratory. In a retrospective study results for serum samples containing amphetamine, methylenedioxy derivatives, cannabinoids, benzodiazepines, cocaine (metabolites), methadone and opiates obtained with CEDIA drugs of abuse reagents on a Hitachi 912 autoanalyzer were compared with quantitative results of chromatographic methods (gas or liquid chromatography coupled with mass spectrometry (GC/MS or LC/MS)). Firstly sensitivity, specificity, positive and negative predictive values and overall misclassification rates were evaluated by contingency tables and compared to ROC-analyses and Youden-Indices. Secondly ideal cutoffs were statistically calculated on the basis of sensitivity and specificity as decisive statistical criteria with focus on a high sensitivity (low rates of false-negatives), i.e. using the Youden-Index. Immunoassay (IA) and confirmatory results were available for 3014 blood samples. Sensitivity was 90% or more for nearly all analytes: amphetamines (IA cutoff 9.5 ng/ml), methylenedioxy derivatives (IA cutoff 5.5 ng/ml), cannabinoids (IA cutoff 14.5 ng/ml), benzodiazepines (IA cutoff >0 ng/ml). Test of opiates showed a sensitivity of 86% for a IA cutoff value of >0 ng/ml. Values for specificity ranged between 33% (methadone, IA cutoff 10 ng/ml) and 90% (cocaine, IA cutoff 20 ng/ml). Lower cutoff values as recommended by ROC analyses were chosen for most tests to decrease the rate of false-negatives. Analyses enabled the definition of cutoff values with good values for sensitivity. Small rates of false-positives can be accepted in forensic cases.     

Relationships between concentrations of cocaine and its hydrolysates in peripheral blood, heart blood, vitreous humor and urine

Cocaine is known to degrade in vivo and in vitro by several hydrolytic mechanisms. A previous study found that the initial amount of cocaine added to plasma could be accounted for by summing the molar concentrations of cocaine's hydrolysis products and the cocaine remaining after hydrolysis. The present study was undertaken to investigate whether or not relationships might exist between such molar concentration sums for different postmortem bodily fluids. Determinations of cocaine, benzoylecgonine, ecgonine methyl ester, and ecgonine were performed using liquid chromatography/mass spectrometry (LC/MS/MS) with heart blood, femoral blood, vitreous humor (VH), and urine (UR). The results demonstrate a strong correlation between blood and VH concentrations (correlation coefficients of 0.88-0.94), weak correlation between the UR and blood concentrations (correlation coefficients of 0.61-0.64), and weak correlation between UR and VH concentrations (correlation coefficient of 0.59). The results demonstrate that ecgonine is a significant hydrolysate with concentrations on the same order of magnitude as benzoylecgonine. The results are consistent with rapid distribution of the parent drug and its hydrolysates in the blood and VH. The strong correlation between the blood and VH demonstrates that VH is an important medium for toxicology testing when attempting to make a determination of cocaine intoxication.     

idPAD: Paper Analytical Device for Presumptive Identification of Illicit Drugs

As drug overdose deaths across the United States continue to rise, there is increasing interest in field testing of illicit substances. This work discusses a paper-based analytical device (idPAD) that can run a library of 12 colorimetric tests at the same time, each detecting different chemical functional groups and materials found in illicit drugs, distractor substances, and cutting agents. The idPAD requires no electricity, costs less than $2 USD, and requires minimal training to operate. The results of the 12 tests form a color barcode which is “read” by comparison to standard images. The accuracy of the idPAD was assessed using samples of heroin, cocaine HCl, crack, and methamphetamine at concentrations of 25%–100% in a lactose matrix, as well as pure lactose. Based on 840 “reads” by three different users, the idPAD showed 95% sensitivity and 100% specificity for detecting these drugs; the most common error was mistaking cocaine HCl for crack or crack for cocaine HCl. In a second step, samples of heroin, cocaine, and methamphetamine (n = 30) and distractor substances (pharmaceuticals, cutting agents, and other illicit drugs, n = 64) were tested by two readers, yielding a sensitivity of 100% and specificity of 97%. Targeted substances were detected reliably at 55–180 μg/lane, and the idPAD was found to be stable for at least 3 months when stored at room temperature. The library approach used in the idPAD may provide the accuracy and robustness necessary for a presumptive field drug test.     

Proficiency test for the analysis of hair for drugs of abuse,organized by the Society of Hair Testing

Eighteen laboratories interested in the analysis of human hair for drugs of abuse participated in a proficiency test (PT) organized by the Society of Hair Testing (SoHT) in 2001.Samples sent to the participants included one drug-free hair sample and two samples from drug users, sent in the form of short segments previously checked for homogeneity by three reference laboratories. Participants were requested to analyze the samples following the standard procedure used routinely in their laboratories.The compounds present in the samples included opiates, cocaine and metabolite, cannabinoids and amphetamines. All the laboratories analyzed opiates, cocaine and benzoylecgonine (BE); only 10 analyzed amphetamines, and 9 cannabinoids. Various methods were used to extract drugs from the hair-enzyme treatment, acidic, basic and methanol extractions. All the laboratories employed GC-MS, with the exception of two which used GC-MS/MS and LC-MS/MS, respectively. Six laboratories performed initial screening tests by RIA, ELISA or EMIT.Results show that the laboratories performed well qualitatively, since they successfully identified all the analytes that they tested, with the exception of eight false results. However, the scatter of quantitative results was high.     

Cocaine-related death

Cocaine use and abuse, an ancient custom, is once again commonplace. While severe toxicity appears to be rare, overt poisoning including death can occur. This report documents nine cases of death associated with cocaine use; in three of these cocaine appears to be causative. Toxicologic analysis of body fluids and tissues was affirmative and levels are reported. Cocaine should be considered in serious drug overdose-reactions, especially after illicit injection.     

Testing human hair for drugs of abuse. IV. Environmental cocaine contamination and washing effects

Active cocaine use results in sequestration of parent drug in hair. In addition, hair has unique physicochemical properties that permit absorption of cocaine from the environment. When hair is tested for evidence of cocaine, it is important to consider whether the positive test resulted from active drug use or environmental contamination. In a series of laboratory experiments, it was found that exposure of ‘cut’ hair to cocaine vapor (‘crack’ smoke) and to aqueous solutions of cocaine hydrochloride resulted in significant contamination of hair samples. Similar results were obtained with two subjects who were exposed to cocaine vapor in an unventilated room. The amount of contamination adsorbed by hair depended upon both time and extent of exposure. Washing the hair samples with methanol removed >70% of the cocaine contaminant after cocaine vapor exposure, but was less effective (<50%) following contamination with aqueous cocaine. Shampoo treatment cycles (overnight soaking) progressively removed increasing amounts of cocaine from the contaminated hair, but residual cocaine remained after 10 cycles. Studies were also performed to determine the usefulness of benzoylecgonine as a marker of active cocaine administration. Small amounts of benzoylecgonine (ca. 1 ng/mg) were formed in hair as a result of environmental contamination with cocaine. Also, it was found that benzoylecgonine could be adsorbed from illicit cocaine contaminated with benzoylecgonine. It was concluded that positive hair test results should be interpreted cautiously due to the possibility of environmental contamination from cocaine and related constituents.     

Detection of cocaine in blood stains]

Cocaine is rapidly degraded in blood samples, and its degradation was found to be highly dynamic in nature. The analysis of blood spots dried on filter paper may provide a method to minimize the break-down of cocaine and to largely preserve the analytical profile of the parent drug and its hydrolysis products at the time of sampling. The short term stability of cocaine in 100 microL blood spots prepared from unpreserved and preserved (sodium fluoride, 0.25%) blood samples was compared to the stability of the particular whole blood specimens stored in tubes at ambient temperature and at -20 degrees C. Due to dehydration, both the chemical and the enzymatic hydrolysis of cocaine and its products could be stopped in dried blood spots. More than 75% of the initial cocaine concentration could be detected in the blood spots, and the analytical profile was ensured for 17 days. Provided its practical suitability, the spot technology should offer a simple approach to detect actual impairment of motorists taken in police custody in the view of section 24a of the German traffic act as well as in cocaine associated criminal cases.