Application
News
No.
n Introduction
n Sample
n Sample Preparation
n Instrument and Analytical Conditions
n Analysis
Herbal medicines, products consisting of animals and
plants, fungi, and minerals with naturally occurring
efficacy, are used without purification as drugs (over-
the-counter drugs), foods, functional foods, and dietary
supplements. Safety standards for harmful elements
used in pharmaceuticals are provided for in each
country. Table 1 shows examples of regulations
regarding the permissible levels of harmful elements in
herbal medicines, including the levels suggested by
WHO
1)
and the import/export reference values of
China
2)
.
Here, using the Shimadzu ICPE-9800 series multi-type
ICP atomic emission spectrometer, we conducted an
analysis of an herbal medicine. The ICPE-9800 series,
with its mini-torch plasma and spectrometer which
permits all element/all wavelength simultaneous
analysis, provides high sensitivity, high precision, and
high throughput at low cost.
Element As Cd Cu Hg Pb
WHO recomended value 0.3 10
China Import/Export
Herbal Medicine
Reference Value
2 0.3 20 0.2 5
Table 1 Harmful Element Regulation of Herbal Medicines (mg/kg)
Herbal medicines distributed in Japan.
Low boiling point-elements such as arsenic (As),
mercury (Hg), etc. are subject to loss due to
volatilization during operations such as heating and
acid addition. Therefore, a pretreatment process is
required that will keep element loss to a minimum,
while at the same time be efficient. Here, we
conducted sample digestion using a microwave sample
preparation system.
To 0.5 g of dry sample, 7.5 mL of concentrated nitric
acid and 0.5 mL of concentrated hydrochloric acid were
added, and digestion was conducted using a
microwave sample preparation system. After digestion,
distilled water was added to the process liquid to bring
the total volume to 25 mL, and this was used as the
analytical sample. Separately, after preparing another
sample in the same manner, a standard solution
containing the target elements was added, and this
served as the spike-and-recovery test solution.
For measurement, the Shimadzu ICPE-9800 series
multi-type ICP emission spectrometer was used. The
analytical conditions used are shown in Table 2. The
adoption of an echelle spectrometer and a CCD
detector permits simultaneous analysis of all the
elements at all the wavelengths, in addition to high-
throughput measurement even with many target
elements and samples. Also, the mini-torch plasma, Eco
mode, and vacuum-housed spectrometer serve to
greatly reduce running costs due to gas consumption.
Herbal medicines often contain large amounts of
coexisting elements, including calcium (Ca), potassium
(K), and magnesium (Mg). Typically, when a sample
contains many coexisting elements, some level of error
may affect the analysis value due to ionization
interference. However, the ICPE-9800 series mini-torch
produces a high-temperature plasma which in addition
to providing high sensitivity, also suppresses the effect
of ionization interference.
Table 2 Analytical Conditions
Instrument : ICPE-9800 series
Radio Frequency Power : 1.2 kW
Plasma Gas Flowrate : 10 L/min
Auxiliary Gas Flowrate : 0.6 L/min
Carrier Gas Flowrate : 0.7 L/min
Sample Introduction : Nebulizer 10
Misting Chamber : Cyclone chamber
Plasma Torch : Mini Torch
Observation : Axial (AX)
Measurement Time : 2.5 min/sample (Including rinse time)
Quantitative analysis of As, Cd, Cr, Cu, Hg, Pb, and Sn
was conducted using the calibration curve method.
[References]
1) WHO Guidelines for Assessing Quality of Herbal Medicines with
Reference to Contaminants and Residues (Japan Self-Medication
Industry, published March 2009)
2) Green Trade Standards of Importing & Exporting Medicinal Plants &
Preparations (Ministry of Foreign Trade and Economic Cooperation,
People's Republic of China, effective July 1, 2001)
J101A
Inductively Coupled Plasma Atomic Emission Spectrometry
Analysis of Harmful Elements in Herbal Medicines
by ICPE-9800 Series
LAAN-A-CP-E014A
