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Monitoring Metals Hypersensitivity by
Measuring Chromium, Cobalt and Molybdenum
in Whole Blood
Elzbieta (Ela) Bakowska, Judy Vinosky and Michael Welsh
NMS Labs, Willow Grove, Pennsylvania, USA
INTRODUCTION
METHODOLOGY
Metal hypersensitivity is commonly reported in the literature and can include
hypersensitivity related to pacemakers, dental implants and orthopedic hardware.
Up to 13% of people are reported to be sensitive to nickel, cobalt, or chromium.
Some patients who have undergone an orthopedic joint replacement, are monitored
for Chromium, Cobalt and Molybdenum levels in blood.
Challenges and Solutions
There are many challenges associated with measurements of Cr, Co and Mo in
whole blood: individual patients variability, contamination issues and analytical
instruments’ complexities.
Cobalt and chromium blood levels can change depending on physical condition of
the patient, working environment, individual feeding and metabolism.
The normal range for Chromium in blood is listed as 0.5 - 5 mcg/L, for Cobalt in
blood is 0.5-3.9 mcg/L, and for Molybdenum in blood is below 3 mcg/L.
Dealing with such low levels in biological materials presents additional challenges.
Use of non-certified for trace element analysis collection tubes may cause
contamination. The contamination control during the specimens’ preparation and
analysis required additional attention. The samples preparation and analyses were
performed in a clean-room environment.
Agilent 7500ce ICP-MS was used for the determination of Cobalt and
Molybdenum. In order to further minimize the contamination, the standard
nebulizer system was replaced with 100% PFA cross-flow nebulizer from Savillex.
Determination of Molybdenum at very low levels is additionally complicated by the
potential of carry-over from measuring of a specimen with elevated levels. It was
established that a rinse time of up to 10 minutes was required to minimize the
carry-over issue. This would negatively affect the productivity, if the sample-tosample analysis time will be approximately 12 minutes, this would allow only 5
samples to be analyzed within 1 hour.
Sample Preparation
For determination of Cobalt and Molybdenum by ICP-MS sample was diluted 1:20
with Internal standard solution and analyzed against aqueous calibrators. For
determination of Chromium by GFAAS the samples were diluted 1:2 with 0.2%
Triton-X and analyzed against matrix-matched calibrators.
For matrix-matching blood of non-diabetics was utilized.
INSTRUMENTATION
Instrumentation - 1
Agilent 7500ce Inductively Coupled
Plasma Mass Spectrometry,
CETAC ASX-510 Autosampler,
Savillex cross-flow Nebulizer
Instrumentation - 2
Perkin-Elmer AAnalyst 600 Atomic
Absorption Spectrometer with AS800 Autosampler, THGA Furnace,
Results
Molybdenum
Precision within run: 5.2 – 9.2%
Accuracy within run: +/- 12%
Precision between runs: 8.0 – 10%
Cobalt
Precision within run: 0.9 – 4.9%
Accuracy within run: +/- 12%
Precision between runs: 2.2 – 7.0%
Chromium
Precision within run: 4.4 – 5.9%
Accuracy within run: +/- 11%
Precision between runs: 3.5 – 7.0%
CONCLUSIONS
The Agilent’s 7500ce ICP-MS software provided the “intelligent rinse” option. This
option involved monitoring of the Molybdenum’s signal during the rinse cycle and
comparing it with a pre-set threshold value. As a result, the rinse time was reduced
down to 3 minutes for most of the samples.
At a systemic level, chronic trace metal release could potentially cause adverse
clinical effects.
The developed methods facilitate monitoring of metals (especially Chromium, Cobalt
and Molybdenum) in the patients with arthroplasties.
The analytical protocols were developed to approximate GLP environment.
Future Work
•To include Chromium in ICP-MS panel
•To include additional analytes (Ni, V, Mn) in the panel
Chromium by GFAAS
Wavelength:
357.9 nm, peak
Slit Width:
0.7 nm, low
Measurement:
Peak area
Cuvette:
THGA tube/platform with endcaps
Injection volume: 20 mcL sample; 10mcL modifier
Sample-to-sample:
~3 min/single injection
Cobalt/Molybdenum by ICP-MS
Cones:
Cell:
Intelligent rise:
Sample-to-sample:
Nickel
Off
On
~3 min/triple measurement
REFERENCES
•http://www.medichecks.com/test.cfm?test=MELI\
“Handbook on Metals in Clinical and Analytical Chemistry”, H.G. Seiler, A.
Sigel and H. Sigel, Eds.
“Metals-derivatized Major Metals Histocompatibility Complex: Zeroing in
on Contact Hypersensitivity”, J. Loh and J. Fraser, The Journal of
Experimental Medicine, Vol. 197, No.5, March 3, 2003, pp.349-552
“The release of metals from metal-on-metal surface arthroplasty of the
hip”, I. Iavicoli et al., Journal of Trace Elements in Medicine and Biology,
Vol. 20, No.1, (2006), pp..25-31
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