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LC-PAD Determination of Mescaline
in Cactus ‘‘Peyote’’ (Lophophora williamsii)
Raquel Casado
1
,In˜igo Uriarte
1
, Rita Yolanda Cavero
2
, Maria Isabel Calvo
1,&
1
Department of Pharmacy and Pharmaceutical Technology (Pharmacognosy Section), University of Navarra, C/Irunlarrea s/n,
Pamplona 31080, Navarra, Spain; E-Mail: mcalvo@unav.es
2
Department of Plant Biology (Botany Section), University of Navarra, C/Irunlarrea s/n, Pamplona 31080, Navarra, Spain
Received: 27 September 2007 / Revised: 10 January 2008 / Accepted: 14 January 2008
Online publication: 15 February 2008
Abstract
A reversed-phase column liquid chromatographic method for the separation and quantifi-
cation of mescaline present in ‘‘peyote’’ has been developed using a Symmetry C
18
column
and isocratic profile. The method can be utilised for the quantitative determination of other
alkaloids. This method is economical in terms of the time taken and the amount of solvent
used for each analysis. The validity of the method with respect to analysis was confirmed by
comparing the UV spectra of peak with the reference compound (mescaline) using a
photodiode array detector. The assay method described is simple, rapid and accurate, and
may form part of future drug authentication protocols.
Keywords
Column liquid chromatography
HPLC-DAD
Validation
Mescaline and peyote
Lophophora williamsii
Introduction
Lophophora williamsii (Lem. Ex Salm-Dyck)
Coult (Cactacae) better known as
peyote,isasmall,spinelesscactuswhose
native region extends along the south-
western United States [1], it is a con-
trolled substance, illegal in all 50 states
[2]. Both peyote and mescaline are listed
in the CSA as Schedule I hallucinogens.
Mescaline is listed as a Schedule III
controlled substance under the Canadian
Controlled Drugs and Substances Act,
but peyote is specifically exempt.
Peyote contains a large spectrum of
alkaloids, the principal of which is mes-
caline (Fig. 1). Although chemically
unrelated to lysergic acid diethyl amide
(LSD), the hallucinogenic effects of
mescaline are similar to that of LSD,
although they are longer lasting [3].
Typical hallucinogenic doses range from
200 to 500 mg (equivalent to roughly 5 g
of dried peyote) of the mescaline [4].
In the literature a number of methods
for the analysis of peyote alkaloids have
been described: TLC [5–9]; GC with
different detectors [3,10–13]; Ion-inter-
action LC [14] and LC-EI-MS [13],
but there are no references about
LC-PAD methods for their detection
and quantification.
The aim of the present study was to
analyse mescaline using a newly and
rapid developed LC-photodiode array
detection (PAD) method that offered
clear advantages as compared with the
previously described methods. Further,
the developed method was validated on
according to ICH guidelines [15]. This
method can be employed for the
quantification of mescaline in cactus
peyote.
Experimental
Plant Material and Reagents
D. Jose Antonio de Arı
´stegui supplied
the peyote sample analysed. Dr. R. Y.
Cavero authenticated the voucher speci-
2008,67, 665–667
DOI: 10.1365/s10337-008-0553-2
0009-5893/08/04 2008 Friedr. Vieweg & Sohn Verlag/GWV Fachverlage GmbH
Limited Short Communication Chromatographia 2008, 67, April (No. 7/8) 665
men deposited in the PAMP Herbarium
(No. 20068) of the Faculty of Sciences
(University of Navarra). Acetonitrile
and phosphoric acid were of LC grade
(Merck, Darmstadt, Germany). Distilled
water was deionised, double distilled
using a quartz distillation unit and fil-
tered through a 0.45 lm filter before use.
Mescaline (1) was purchased from Sigma
(St Louis, MA, USA).
Preparation of Standard
Solutions
Standard solutions were prepared dis-
solving mescaline (5 mg mL
1
) in meth-
anol, since the drug is freely soluble
in this solvent. Further dilutions were
prepared by transferring 0.5–2.5 mL
aliquots of stock solution to 5 mL
volumetric flasks.
Preparation of Sample
Solutions
The plant material was shade dried and
powdered coarsely before extraction. In
order to eliminate possible interfering
with lipids the peyote sample (1 g) was
pre-extracted with diethylether (four
times ·5 mL; 24 h shaking) at room
temperature. After drying the extraction
thimble, the sample was extracted with
methanol-concentrated ammonia solu-
tion (99:1) (five times ·5 mL; 24 h
shaking) at room temperature. This
solution was concentrated at reduced
temperature (40 C) on a rotary evapo-
rator (Bu
¨chi, Labortechnik AC, Flawil,
Switzerland) and redissolved in metha-
nol yielding a volume of 10.0 mL. Two
millilitres of this solution were filtered
through an LC filter and placed in an
autosampler vial of 2 mL.
Apparatus and
Chromatographic Conditions
Analysis was performed using a liquid
chromatograph with Waters (Milford,
MA, USA) pumps (Waters 515) equip-
ped with online degasser, a Waters PCM
(pump control module), a Waters 2996
photodiode array detector and Waters
Empower software. Separation was
carried out using a Nova-Pak C-18
(150 ·3.9 mm, i.d., 4 lm).
Elution was carried out in an isocratic
solvent system at a temperature of 25 C,
a flow rate of 1 mL min
1
and a run time
of 8 min. The mobile phase consisted of a
mixture of water (pH = 2): acetonitrile
(90:10 w/w). The injection volume was
20 lL, the detection wavelength was
268 nm, whilst PDA scans were measured
using a wave step of 2 nm.
Method Validation
The precision of peak area responses for
six replicate injections of a standard
solution of mescaline was determined.
Repeatability of the method was affirmed
by multiple measurements (n=6) of
mescaline under the same analytical and
laboratory conditions and was expressed
as %RSD. Variability of the method was
studied by analysing aliquots of standard
solutions of mescaline on the same day
and on different days (inter-day preci-
sion) and the results were expressed as
%RSD.
Accuracy of the method was tested
by performing the recovery studies at
three levels. To 1 g of powered sample of
L. williamsii known amounts of mesca-
line (50, 100 and 150 mg) were added,
extracted and estimated as described
above. The percentage recovery as well
as average percentage recovery was
calculated.
Linearity of the method was verified by
analysing in triplicate, three solutions of
mescaline in the range of 5–200 lgmL
1
.
Chromatographic signals were fitted to
linear graphs using least square
regression.
Results and Discussion
We report an LC method for quantifica-
tion of the mescaline content in cactus
‘‘peyote’’. Under the conditions used the
most successful solvent system consisted
of a mixture of water (pH = 2) and ace-
tonitrile (90:10 w/w) which gave the best
resolution of mescaline in the presence of
other compounds in the extract (Fig. 2).
Peak identity of mescaline in the sample
extracts was confirmed by overlaying its
UV absorption spectrum with that of the
standard mescaline. Purity of mescaline in
the sample extract was confirmed by
comparing the absorption spectra at start
middle and end position of the peak.
The method was validated in terms of
precision, repeatability, accuracy and
linearity. The precision of the method was
determined by repeatability (intra-day)
and intermediate precision (inter-day).
The intra-day coefficient of variation was
0.4–0.7% for mescaline, and the inter-day
coefficient was 0.6–0.8%. Results indicate
good repeatability and low inter-day
variability (RSD maximum 1.0%). Good
linearity was observed over the concen-
tration range of 5–200 lgmL
1
, with
a correlation coefficient of 0.9992 and
the linear regression equation y=
10675x+ 65642. The percentage recov-
ery at three different levels was found to
be 99.9 ± 0.898% and was considered
highly satisfactory. The limits of
detection (LOD) and the limits of quan-
tification (LLOQ) were 0.28 and 1.40 lg
of mescaline, respectively.
Application of the LC Method
Five percent of the world’s total popu-
lation over the age of 15 are using illicit
drugs, and several hundred thousands of
drug intoxications are reported each year
in the western world alone. Forensic
scientists and law enforcement agencies
require screening methods used in
forensic intoxication cases to be highly
sensitive and fast. Considering the short
runtime, this validated method offers a
CH3O
CH3O
CH3O
NH2
Fig. 1. Structure of mescaline
666 Chromatographia 2008, 67, April (No. 7/8) Limited Short Communication
clear improvement over previously pub-
lished methods for the rapid qualitative
and quantitative analysis of mescaline in
toxically determinations.
Conclusion
In conclusion, this report is the first
using LC-PAD for a direct quantifica-
tion of the mescaline content in peyote
cactus. The isocratic LC method
described is rapid, and provides a good
baseline separation of mescaline at
2.07 min retention time. Also the good
recovery, linearity, precision and accu-
racy, as well as the excellent LOD
and LLOQ values, make this
method suitable as a standard analytical
procedure.
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Fig. 2. LC profile of the peyote extract (1= mescaline)
Limited Short Communication Chromatographia 2008, 67, April (No. 7/8) 667
