Lecture 10

Question 1

what are new psychoactive substances (NPS) ?

Answer 1

not regulated substances that show a similar effect to known drugs

Question 2

what is the problem with rhesus for pregnant women ?

Answer 2

If mother Rh- and first kid Rh+ : at birht, mom will develop anti-rh antibodies. If second Rh+ foetus, it will be attacked and killed.

Question 3

how is the blood pH regulated ?

Answer 3

Buffer systems :
- bicarbonate (main)
- hemoglobin
- protein
- phosphate

Question 4

difference between plasma and serum

Answer 4

plasma : when blood is not clotted, so plasma contains coagukation factors

serum : blood is clotted so coagulation factors are excluded

Question 5

sample preparation : choice of matrix, extraction, extraction procedures

Answer 5

serum / plasma : mainly water soluble analytes, disturbing blood components are eliminated, but lipophilic components can get lost
whole blood : all possible analytes, lipophilic are included but sample prep is more complicated

extraction : volatile by heating, solvent -> precipitation, SPE/LLE

SPE : sample loading on column, washing, and eluding
LLE : add organic phase with more affinity to sample, extract the phase

Question 6

urine : 2 tasks, formation way, components

Answer 6

excretion of pathogens and water balance regulation.

formation in kidney : glomerular filtration - reabsorption - secretion

mainly water, and then other things (important : creatinine)

Question 7

2 ways for immunochemical testing, explain methods of second

Answer 7

1) dipping test (lateral flow essay)

2) immunochemical assays (ELISA) : direct, indirect, sandwich, competitive ; main principle is an enzyme-conjugated antibody -> colored substrate

Question 8

a few differences between blood and urine

Answer 8

blood : shorter detection window, invasive, mostly quantitative

urine : longer detection window, non-invasive, mostly qualitative

Question 9

vitrous humour : where, 4 main tasks, composition

Answer 9

Inside of eye (NOT aqueous humour).
Provides nutrients, lets light in, connects to retina, keeps shape of eye.
Mostly water. Hyaluronic acid, collagen, ions. (gel-like)

Question 10

advantage of vitrous humour against blood/urine ? what should be done before analysis ?

Answer 10

More stable post-mortem, not that affected if diceased. Should be frozen and thawed before analysis.

Question 11

pros and cons of vitrous humor

Answer 11

+) easy handling, stable post-mortem, beat matrix for special questions
-) difficult, invasive sampling, gel-like texture

Question 12

synovial fluid : pros and cons

Answer 12

+) easy handling, routine sampling, easy to draw in animal models

-) invasive sampling, in forensic context little is known about that matrix (not used that much)

Question 13

cerebrospinal liquid : pros and cons

Answer 13

+) easy handling, more or less stable post-mortem, post-mortem easy to draw

-) difficult, invasive sampling

Question 14

another alternative matrix ? how does it work as a matrix ?

Answer 14

hair follicle. Connected to blood vessels + sweat and greasy scalp

Question 15

pros and cons of hair follicle as a matrix

Answer 15

+) monitoring for a long time, analytes insentitive to washing, obvious attempted fraud, easy sampling

-) sample prep is really demanding, hydrophilic analytes can be washed out, hair treatments can destroy hair anatomy

Question 16

where else can we get info from ? (organ) What is one issue ?

Answer 16

Liver.
We can say if intake took place, but not WHEN, and drugs can be redistributed into blood from solid organs after death

Question 17

4 possible analytes in forensic toxicology

Answer 17

• alcohol
• drugs of abuse
• medication
• special (gases, NPS)

Question 18

analysis : what needs to be done first, name different detectors

Answer 18

1) sample separation : gas or liquid chromatography (depends on physico-chemical prop of sample)

Detectors : diode array, flame ionization, nitrogen phosphorous, mass spectrometry