Methods for impurity profiling of heroin and cocaine



Yüklə 0,54 Mb.
Pdf görüntüsü
səhifə9/29
tarix14.05.2018
ölçüsü0,54 Mb.
#44322
1   ...   5   6   7   8   9   10   11   12   ...   29

Methods for impurity profiling

17

Method A1:

High-performance liquid chromatography (HPLC) method*

Source: I. S. Lurie and S. M. Carr, “The quantitation of heroin and selected basic

impurities via reversed phase HPLC: I. The analysis of unadulterated heroin samples”,



Journal of Liquid Chromatography and Related Technologies, vol. 9, No. 11 (1986),

pp. 2485-2509.



Sample type: Major components: cut and uncut samples.

Operating conditions:

Detector:

Ultraviolet diode array

Monitor 3 wavelengths: 210 nm, 228 nm and 240 nm

Column:

Partisil 5, ODS 3, 125 mm x 3.2 mm ID



Mobile phases:

(a) Phosphate buffer (pH 2.2)

(b) Methanol

Injection solvent: HPLC-grade water, acetonitrile and glacial acetic acid

(89:10:1), adjusted to pH 3.7 with 2M sodium hydroxide

Flow rate:

0.76 ml/min

Injection size:

20 µl

Elution gradient:



Equilibration

Time

MeOH (%)

Buffer (%)

15

5



95

1

20



30

70

2



6

30

70



3

10

80



20

4

4



80

20

5



5

5

95



Internal standard: propiophenone at 0.5 mg/ml in injection solvent

Phosphate buffer: 870 ml of HPLC-grade water, 30 ml of 2N sodium hydroxide and

10 ml of phosphoric acid. Filter and degas, then add 3.0 ml hexylamine. The final

pH is adjusted to pH 2.2 with 2M sodium hydroxide or phosphoric acid. Add addi-

tional hexylamine as necessary for baseline separation of papaverine and noscapine. 



Sample preparation: Accurately weigh the sample into a 100-ml volumetric flask to

give an approximate heroin concentration of 0.9 mg/ml. Add 10 ml of propiophenone

internal standard solution and dilute to volume with injection solvent. Sonicate to com-

plete solvation and filter.



Rationale for use: A robust method providing accurate quantification and excellent

precision for heroin and all typical opium alkaloid impurities down to 1% relative to

heroin content. In many cases minor alkaloids and adulterants can be quantified at

*This HPLC method is a slightly modified version of the “classic” heroin signature 1 method

used by the Drug Enforcement Administration (DEA) of the United States of America in its heroin

origin determination programme, until it was replaced in 2003 by a capillary electrophoresis (CE)

method (method A6).



18

Methods for impurity profiling of heroin and cocaine

Method A2:

GC method, without derivatization

Source: Modified from C. Barnfield and others, “The routine profiling of forensic

heroin samples”, Forensic Science International, vol. 39, No. 2 (1988), pp. 107-117.



Sample type: Major components: cut and uncut samples.

Operating conditions:

Detector:

Flame ionization detector (FID)

Column:


DB-1, PB1 or equivalent, 25 m x 0.32 mm x 0.5 µm

Carrier gas:

Helium

Make-up gas:



Not specified

Injection:

1 µl; split 30:1

Temperatures:

Injector: 280° 

C

Detector: 320° 



C

Oven:


200° C to 260° C at 10° C/min, to 310° C 

at 30° C/min, hold for 1 min



Internal standard: None: normalize all data relative to heroin response.

Sample preparation: Weigh out the powder and dissolve initially in one part of N,

N-dimethylformamide,* then dilute with nine parts of ethanol to give a final concen-

tration of 3-5 mg/ml of sample, depending on the heroin concentration.

levels as low as 0.1% relative to heroin content along with significant but generally

acceptable losses in precision. The minor alkaloids quantified are morphine, codeine,

O3MAM, O6MAM, papaverine and noscapine. As is the case with every analytical

procedure for heroin, hydrolysis can be an issue, but if the method is followed pro-

perly, hydrolysis will be kept to an absolute minimum. The original reference states:

“Quantitative values of the various basic impurities relative to heroin in the samples

analysed were found to vary over a large range and formed a basis for comparing

illicit heroin samples.” The on-column heroin content specified in this method typi-

cally produces an UV-detector response that is in the upper region of detector linear-

ity. Hence, it is necessary for the analyst to obtain a “rough” quantification of the

heroin prior to analysis by this method. Any of the following GC methods designed

for major impurity analyses can be utilized for this purpose. The use of a photo-diode

array (PDA) detector is recommended as it allows the facile detection of co-eluting

compounds, that is, peak purity assessments. Precision and accuracy for morphine are

somewhat limited, as morphine elutes very soon after column void volume. Common

co-elution issues occur for acetaminophen (paracetamol) with codeine, cocaine with

acetylcodeine and diphenhydramine with noscapine. Sugars are not detected. 

Outcome: Indication of general source region (South-East Asia, South-West Asia,

Mexico and South America). Sample comparisons for discrimination and evaluation

of samples for case-to-case evidential purposes (linkage determinations). Additional

information is required to confirm links between samples or to assign source regions,

that is, the method should be used as one part within a broader analysis scheme.

*The use of N,N-dimethylformamide facilitates the dissolution of samples containing large

proportions of caffeine, phenacetin and/or paracetamol.



Yüklə 0,54 Mb.

Dostları ilə paylaş:
1   ...   5   6   7   8   9   10   11   12   ...   29




Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur ©genderi.org 2024
rəhbərliyinə müraciət

    Ana səhifə