Biomedical Engineering Reference
In-Depth Information
compared these data with those related to other pretreatment such as LLE and SPE
[
93,
112,
113
], proving that no great improvement was achieved [
114
] .
10.2.2
LLE
Simões et al. have published an analytical method for the confirmation and quantita-
tion of 24 substances, including opiates, amphetamines, cocaine, methadone, THC,
benzodiazepines, and other medicines [
109
]. OF samples were collected in a Saliva
Sampler collection device, followed by LLE. The samples were transferred into a
tube, containing a buffer solution at pH 9 and a mixture of organic solvents, to extract
organic bases and some neutral drugs from the biological matrix. Chromatographic
separation was performed using gradient elution with acetonitrile/2 mM ammonium
formate buffer and 2 mM ammonium formate buffer. This fully validated method has
demonstrated a great feasibility to DUIDs real cases applications. However, LLE
recoveries are not quantitative at lower concentrations.
10.2.3
Microwave Assisted Extraction
An interesting study was performed by Fernandez et al. to compare two extraction
procedures for the determination of drugs of abuse [
110
] . Targeted analytes were
morphine, 6-MAM, cocaine, CE, BEG, methadone, and 2-ethylene-1,5-dimethyl-
3,3,-diphenylpyrrolidine.
OF samples were collected with the commercial device Salivette, which consists
of a cotton swab that is inserted into the mouth for 2-3 min. Toxitubes A was com-
pared to microwave assisted extraction (MAE). A volume of 1 ml of saliva was
poured into each Toxitube and treated similarly as seen previously [
109
] . For MAE
different solvents (chloroform, dichloromethane, hexane), temperatures (80, 90,
and 100 °C), and time periods (5, 10, and 15 min) have been tested; finally 1 ml of
saliva was mixed with 10 ml of chloroform and placed in the oven vessel for extrac-
tion at 100 °C for 10 min. Recoveries were found to range from 53 to 95 % with
Toxitubes and from 83 to 100 % with MAE, so authors demonstrated that micro-
wave-assisted extraction provides recoveries higher than those obtained for opiates
with SPE.
10.2.4
SPE
Kala et al. proposed a similar multiclass method in 2008 for the simultaneous deter-
mination of amphetamines, opiates, PCP, and cocaine and BEG. In this paper the
difficulty of establishing a common step of sample preparation for all of the sub-
stances is demonstrated. OF samples, collected by OF collection kits, were analyzed
after screening. Amphetamines and PCP were extracted by LLE, while for opiates,
cocaine and BEG extractions, authors used an SPE strategy. The separation of
