Chemistry Reference
In-Depth Information
related to occupational exposure to beryllium are
linked to the higher exposure levels that were as-
sociated with acute beryllium pneumonitis and pre-
dominated before the 1950s.
heparin as an anticoagulant may contaminate whole
blood samples (Toxicological Profi le, 2002).
The detection limit of the GFAAS methods is at
0.05
µ
g/L (Paschal and Bailey, 1986; Shan
et al
., 1989) or
0.06
g/L of urine (Wegner
et al
., 2000). ICP-MS meth-
ods include those of Paschal
et al
. (1998), providing
the detection limit of 0.1
µ
1 PHYSICAL AND CHEMICAL PROPERTIES
g/L or the recently pub-
lished method by Apostoli and Schaller (2002), who
adapted the method of Schramel
et al
. (1997). The
detection limit of this method is 0.03
µ
Elemental beryllium, atomic number 4 in group
IIA of the periodic table, is a hard, brittle, steel gray,
lightweight metal, and has the unusually high melting
point of 1278°. With an atomic weight of 9.0122, beryl-
lium is one of the lightest elements.
Consistent with the high charge-to-radius ratio,
beryllium has a strong tendency to form compounds
with covalent bonds; even the compounds with the most
electronegative elements (e.g., BeF
2
) have a substan-
tially covalent character. Although beryllium belongs
to group IIA of the periodic table, it is chemically very
similar to aluminium, which also has a high charge-to-
radius ratio. The metal has very high specifi c heat, heat
of fusion, sound conductance, and stiffness-to-weight
ratio. In alloys, it confers on other metals improved
resistance to fatigue, vibration, and shock. It also has an
extreme hardness and resistance to corrosion, attribut-
able to a thin fi lm of beryllium oxide rapidly forming
on the surface of bare metal on exposure to air.
The chloride, fl uoride, nitrate, and sulfate are highly
soluble in water. The metal, its carbonate hydroxide,
phosphate, and acetate are sparingly soluble in water
but dissolve in acids or bases. Beryllium oxide, prepared
by calcinating the hydroxide between 500°and 1750°C,
is sparingly soluble in water, whereas oxide calcinated
above 1750°C is considered to be insoluble. There is
ample evidence that all chemical reactivity, includ-
ing toxicity, of beryllium oxide is inversely related to
the temperature of fi ring (Reeves, 1986; Toxicological
Profi le, 2002).
g/L of urine,
and the between-series imprecision for a concentration
of 0.5
µ
g/L expressed as relative standard deviation is
9.5%. According to Apostoli and Schaller (2002), the
“normal” urinary Be concentrations reported previ-
ously in literature were too high, mainly as a result of
the poor specifi city and sensitivity of the adopted ana-
lytical methods. For example, in the reports published
after 1990, the mean urinary beryllium concentrations
in nonoccupationally exposed persons amounted to
0.4
µ
g/L (Paschal
et al
., 1998). On the other hand, in the control groups
investigated by Wagner
et al
. (2000) or Apostoli and
Schaller (2002), all the results of determinations were
below the detection limits of 0.06
µ
g/L (Minoia
et al
., 1990) and 0.28
µ
µ
g/L or 0.03
µ
g/L,
respectively.
The determination of beryllium in lung tissue was
used to differentiate between chronic berylliosis and
sarcoidosis. The analyses for beryllium in the autop-
sied lung tissues were performed with GFAAS after
digestion of lung tissue with the mixture of nitric
acid and perchloric acid (Verma
et al
., 2003) or atmos-
pheric thin-window energy-dispersive X-ray analysis
(ATWEDXA) (Buntor
et al
. , 2003).
3 PRODUCTION AND USES
3.1 Production
Metallic beryllium was isolated in 1828. However,
beryllium was not used extensively until a 1920s' dis-
covery that 2% addition of beryllium to copper pro-
duced an alloy six times stronger than the original
material. Beryllium is mined primarily from naturally
occurring silicates including beryl (Al
2
Be
3
Si
6
O
18
, 5%
beryllium by weight) and bertrandite (Be
4
(OH)
2
Si
2,
15% beryllium by weight). The world resources of
beryllium are estimated at approximately 80,000 tons
(Taylor
et al
., 2003).
The extraction of beryllium begins with the raw
materials (bertrandite ore and/or beryl ore). The
extraction process for beryl ore involves melting, frit-
ting, and grinding of the ore followed by reacting it
with sulfuric acid to produce water-soluble sulfate.
2 METHODS AND PROBLEMS
OF ANALYSIS
Neither the fl ame atomic spectroscopy (AAS) nor
atomic emission spectroscopy (AES) used in the past
have adequate sensitivity for measuring beryllium con-
centrations found in body fl uids and tissues. Graphite
furnace atomic absorption spectroscopy (GFAAS) with
background correction (deuterium or Zeeman effect)
and inductively coupled plasma atomic emission spec-
troscopy are now common analytical methods. To avoid
sample contamination, stainless steel needles should be
avoided for the collection of whole blood samples. Cer-
tain polyethylene sample collection tubes with added
