This document provides key analytical applications to help laboratories address the pressing concerns of the changing global landscape. Specifically, Volume 1 includes applications for Children's Product Safety, Environmental, Food & Beverage and Semiconductor.
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Spotlight on Analytical Applications Complete e-Zine Vol. 1
1. SPOTLIGHT
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FOR A BETTER
TOMORROW.
VOLUME 1
2. INTRODUCTION
PerkinElmer Spotlight on Applications e-Zine – Volume 1
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3. CONTENTS
Children’s Product Safety
• Determination of Formaldehyde Content in Toys using UV/Vis Spectrometry
• Determination of Hexavalent Chromium in Toys using UV/Vis Spectrometry
• UHPLC Separation and Detection of Bisphenol A in Plastics
• Lead & Other Toxic Metals in Toys Using XRF Screening and ICP-OES Quantitative Analysis
Environmental
• Increased Laboratory Productivity for ICP-OES Applied to U.S. EPA Method 6010C
• Increased Sample Throughput for ICP-OES Applied to U.S. EPA Method 200.7
• Determination of Total Mercury in Soils and River Sediments using Thermal
Decomposition and Amalgamation Coupled with Atomic Absorption
• Determination of Total Mercury in Whole Blood using Thermal Decomposition and
Amalgamation Coupled with Atomic Absorption
Food & Beverage
• Determination of Arsenic in Baby Foods and Fruit Juices by GFAAS
• Determination of Total Mercury in Fish and Agricultural Plant Materials using Thermal
Decomposition and Amalgamation Coupled with Atomic Absorption
• Increased Throughput and Reduced Solvent Consumption for the Determination of
Isoflavones by UHPLC
• Extraction and Quantification of Limonene from Citrus Rinds using GC/MS
Semiconductor
• Analysis of Impurities in Semiconductor Grade Hydrochloric Acid by Dynamic
Reaction Cell ICP-MS
• Analysis of Impurities in Ultrapure Water by Dynamic Reaction Cell ICP-MS
• Analysis of Semiconductor Grade TMAH by Dynamic Reaction Cell ICP-MS
• Analysis of Impurities in Nitric Acid by Dynamic Reaction Cell ICP-MS
PerkinElmer
4. a p p l i c at i o n n o t e
Children’s Products
Author
Aniruddha Pisal
PerkinElmer, Inc.
Shelton, CT 06484 USA
Determination of Figure 1. LAMBDA XLS+ UV/Vis spectrometer.
Wavelength: 410 nm; Measurement Mode:
Formaldehyde Content
Absorbance; Cell 10 mm.
in Toys using UV/Vis
Spectrometry
Introduction
As product safety regulations for industry are becoming stricter, more testing at lower levels is required for toxic
elements or hazardous organic chemicals such as formaldehyde in children’s toys/clothing. Formaldehyde resins
are used in fabrics to bind pigments to the cloth, as a fire retardant and to provide stiffness. In cotton and cotton-
blend fabrics they are used to enhance wrinkle resistance and water repellency. They can often be noted by the
odor of treated fabric. The types of resins used include urea-formaldehyde, melamine-formaldehyde and phenol-
formaldehyde. Resins without formaldehyde are typically much costlier. Increases in temperature (hot days) and
increased humidity both increase the release of formaldehyde from coated textiles.
Long term chronic exposure or short-term exposure to high concentrations of formaldehyde can lead to cancer.
In animal studies, rats exposed to high level of formaldehyde in air developed nose cancer. The European standard
EN 71 specifies safety requirements for toys. EN 71, Part 9 contains requirements for organic chemical compounds
in toys and specifies the limit for accessible textile components of toys intended for children under 3 years of age.
The limit specified for formaldehyde content is not more than 30 mg/kg or 2.5 mg/L in the aqueous migrate pre-
pared following EN 71, Part 10. EN 71, Part 11, section 5.5.3 specifies a method of analysis.
5. Experimental The concentration of formaldehyde was found to be 1.99 mg/L.
The analysis was carried out using a PerkinElmer LAMBDA ® ™
Formaldehyde dilute standard solution (0.001 mg/mL):
XLS+ UV/Vis Spectrometer.
2.5 mL of formaldehyde stock solution was transferred to
50-mL volumetric flask; mixed well and diluted up to the
Apparatus and reagents mark with water. 1 mL of this solution was further diluted
to 100 mL with water and mixed well.
Table 1. List of apparatus and reagents used.*
Volumetric flasks, volume 50 mL A series of reference solutions were prepared by pipetting
Volumetric flasks, volume 100 mL suitable volumes of above formaldehyde dilute standard
Hot plate for distillation solution into a 50-mL conical flask as follows
Boiling chips
Erlenmeyer flasks, volume 100 mL
Table 2. Calibration solutions.
Eppendorf® micropipettes
Concentration
Ammonium acetate, anhydrous Amounts (mL) (mg/L) of
Acetic acid, glacial Formaldehyde Formaldehyde
dilute standard Amount of after making
Pentane-2,4-dione solution in 50-mL pentane-2,4-dione volume to 30 mL
conical flask reagent (mL) with water
Hydrochloric acid, 1 mol/L
Sodium Hydroxide solution 1 mol/L Blank – 5.0 0.0
Starch solution freshly prepared, 2 g/L
Reference 1 5.0 5.0 0.167
Formaldehyde solution, 370 g/L to 400 g/L
Standard iodine solution, 0.05 mol/L Reference 2 10.0 5.0 0.333
Standard sodium thiosulfate solution, 0.1 mol/L
Reference 3 15.0 5.0 0.499
Water, deionized
Stainless steel tweezers Reference 4 20.0 5.0 0.667
250 mL glass bottle with flat base, screw neck and PTFE lined rubber Reference 5 25.0 5.0 0.833
septum (Make: Schott Duran)
Magnetic stirrer
*The reagents, chemicals, standards used were of ACS grade. Absorbance measurement of calibration solutions:
Absorbance measurements of calibration reference solutions
Pentane-2,4-dione reagent: Dissolved 15 gm of anhydrous and blank were done by using water as reference. The calibra-
ammonium acetate, 0.3 mL glacial acetic acid and 0.2 mL tion curve was constructed by subtracting absorbance value of
pentane-2,4-dione reagent in 25 mL water and diluted up the blank solution (A2) from each of absorbances obtained
to the mark in 100-mL volumetric flask with water. from the calibration solutions. Figure 2 shows calibration graph.
Reagent without pentane-2,4-dione: Dissolve 15 gm of Sample preparation: Three different toy samples made up
anhydrous ammonium acetate and 0.3 mL glacial acetic acid with fabrics were selected for analysis. Sample with surface
in 25 mL water and diluted up to the mark in 100-mL volumetric area of 10 cm2 was taken and transferred to 250 mL extrac-
flask with water. tion bottle with the help of tweezers. 100 mL of simulant
(water, deionized) was added to the sample at 20 ˚C ±2 ˚C
Formaldehyde stock solution: Transferred 5.0 mL of and the extraction bottle closed. The extraction bottle was
formaldehyde solution into a 1000-mL volumetric flask kept on a magnetic stirrer for uniform stirring of the solu-
and made up to the mark with water. tion over the period of 60 minutes. Aqueous migrate was
then filtered through a plug of glass wool. 5.0 mL of aque-
Standardization of formaldehyde stock solution:
ous migrate was transferred into a 50-mL conical flask fol-
10.0 mL of freshly prepared formaldehyde stock solution
lowed by addition of 5.0 mL of pentane-2,4-dione reagent
was transferred into a conical flask, added 25.0 mL of a
and 20.0 mL of water.
standard iodine solution and 10.0 mL of sodium hydroxide
solution. The solution was allowed to stand for 5 minutes. Sample reference solution: 5.0 mL of aqueous migrate
Then the solution was acidified with 11.0 mL of hydrochloric was transferred into a 50-mL conical flask followed by
acid and titrated for excess iodine by standard sodium thio- addition of 5.0 mL of reagent without pentane-2,4-dione
sulfate solution. 0.1 mL of starch solution was added when and 20.0 mL of water.
color of the solution became pale straw. After addition
of starch solution, immediately the color was changed to These solutions were shaken for about 15 seconds and
deep blue-black. The titration was continued until the color immersed in a thermostatic water bath at 60 ˚C ±2 ˚C for
changes from deep blue-black to colorless. Similarly, the 10 minutes followed by cooling for about 2 minutes in a
blank titration was performed. The difference between titration bath of iced water.
values of blank and sample was used for calculation of
formaldehyde contents in stock solution.
2
6. Absorbance measurements were done between 35 minutes
and 60 minutes from the time when the conical flasks were
placed in a water-bath at 60 ˚C.
Absorbance measurements of sample solutions were done
by using the reference solution as reference (A1).
Calculation of analyte concentration: Calibration curve
was prepared manually by taking the absorbance values
obtained for calibration reference solutions. To determine
the analyte concentration, absorbance value of blank solution Figure 3. Spectrum of color formed for the determination of ‘Formaldehyde’
(A2) was subtracted from absorbance value of sample solution contents.
(A1). The subtracted absorbance value was then read off
from the manual calibration curve. The formaldehyde content in aqueous migrate was calculated
by using following equation,
Cs(mg/L) = C X 5 where,
Cs = concentration of formaldehyde in the sample
solution (mg/L)
5 = dilution factor of the sample solution.
Results and discussion
Calibration – linearity
The six different levels of calibration standards were prepared
in the range from 0.167 mg/L to 0.833 mg/L with the
reagent blank as first level. Results showed linearity with
a good correlation co-efficient of 0.9994. The calibration
curve is shown in Figure 2. Figure 3 shows the spectrum of
the developed color, confirming the peak maximum at 410 nm.
Method detection limit: 10 replicate reagent blank solutions
were prepared to make an estimate of method detection
limit. To determine method detection limit, seven replicate
aliquots of fortified reagent water (0.1 mg/L) were prepared
and processed through entire analytical method. The method
detection limit was calculated as follows,
MDL = (t) X (s) where,
t = student’s t value for a 99% confidence level and a
standard deviation estimate with n-1 degrees of freedom.
[t = 3.143 for seven replicates].
s = standard deviation of replicate analyses.
The method detection limit was found to be 0.0178 mg/L.
Figure 2. Calibration graph.
3
8. a p p l i c at i o n n o t e
Children’s Products
Author
Aniruddha Pisal
PerkinElmer, Inc.
Shelton, CT 06484 USA
Determination of Introduction
Toy safety is a joint responsibility among governments, the toy industries,
Hexavalent Chromium regulatory bodies and parents. The toy safety regulations are intended
to reduce potential risks children could be exposed to when playing
in Toys by using with toys. Enforcement of the regulations aims to identify those toys
that do not comply with the legislation and remove them from the
UV/Vis Spectrometry market. The toxic elements that may be present in toys are heavy metals
such as antimony, arsenic, chromium, lead, mercury, etc., which can
accumulate in the body and may cause adverse effects. Therefore,
analysis of such elements is important to ensure safety. The European standard EN 71 specifies safety requirements
for toys. EN 71, Part 3 contains one section entitled “Migration of certain elements”. In this section it defines the
limits for element migration from toy materials including hexavalent chromium. In EN 71, Part 3, the limit specified for
migration of chromium is not more than 60 mg/kg. In the environment, chromium is found in several different
forms including two oxidation states as trivalent i.e., Cr(III) and hexavalent i.e., Cr(VI). Cr(III) is considered to be
an essential nutrient for the body. In contrast Cr(VI) is relatively mobile in the environment and is acutely toxic
and carcinogenic. It is widely used in electroplating, stainless steel production, leather tanning, paint, and textile
manufacturing.
During the analysis, sample preparation was carried out using European
method EN 71, Part 3, specifying extraction of sample by hydrochloric
acid for 2 hours at 37 ˚C in darkness followed by colorimetric determination
of hexavalent chromium by 1,5-diphenylcarbazide reagent.
Figure 1. LAMBDA XLS+ UV/Vis spectrometer.
Wavelength: 540 nm; Measurement Mode:
Absorbance; Cell 10 mm.
9. Experimental Absorbance measurement of calibration solutions:
The analysis was carried out using PerkinElmer LAMBDA ® ™ Background correction was performed with blank solution
XLS+ UV/Vis spectrometer as shown in Figure 1. and absorbance of calibration reference solutions were
measured at 540 nm using 10 mm cell. Figure 2 shows
the calibration graph.
Apparatus and reagents
Sample analysis: Different toy samples selected for analysis
Table 1. List of apparatus and reagents used.
were, ‘yellow plastic’; ‘green fabric’ and ‘toy coated with
pH meter
paint’. 100 mg of test portion of sample was taken and cut
Volumetric flasks, volume 100 mL
into small pieces. For toy sample with paint coating, the
Erlenmeyer flasks, volume 250 mL
coating layer was scraped off for analysis. The test portion
Water bath
Boiling chips
so prepared was mixed for about 1 minute with 5 mL of
Eppendorf ® micropipettes 0.1 mol/L hydrochloric acid at 37 ˚C ±2 ˚C. pH of the solution
Sodium hydroxide, 1N was adjusted to between 1 and 1.5 with 2 mol/L hydrochloric
Potassium dichromate, dried acid. The mixture was protected from light, kept at 37 ˚C
Nitric acid, concentrated ±2 ˚C and agitated for 1 hour continuously and then allowed
Sulfuric acid, concentrated to stand for 1 hour at 37 ˚C ±2 ˚C. Then the solution was
Sulfuric acid, 0.2 N filtered immediately through a membrane filter and diluted
Phosphoric acid, concentrated to about 90 mL with distilled water. The pH of the solution
Hydrochloric acid, 0.1 M was adjusted to 2.0 ±0.5 using phosphoric acid and 0.2 N
1,5 Diphenylcarbazide sulfuric acid. The solution was transferred to a 100-mL volu-
Acetone metric flask and diluted up to the mark with distilled water.
*The reagents, chemicals, standards used were of ACS grade. 2 mL of diphenylcarbazide solution was added to the
solution and allowed to stand 10 minutes for full color
Chromium stock solution (500 mg/L): Dissolved 141.4 mg development. An appropriate portion was transferred to a 1 cm
of potassium dichromate in water and diluted to 100 mL. absorption cell and measured the absorbance at 540 nm
with the blank as a reference.
Chromium standard solution (5 mg/L): Diluted 1.0 mL
of above chromium stock solution to 100 mL.
Results and discussion
Diphenylcarbazide solution: Dissolved 250 mg of Calibration – linearity
1,5-diphenylcarbazide in 50 mL acetone and stored in The seven different levels of calibration standards were
brown bottle. prepared in the range from 0.1 mg/L to 1.0 mg/L with
reagent blank as first level. Results showed linearity with
Series of reference solutions were prepared by pipetting a good correlation co-efficient of 0.9997. The calibration
suitable volumes of above chromium standard solution, curve is shown in Figure 2.
as shown in Table 2, into 100-mL volumetric flasks.
Spike recovery studies:
Table 2. Calibration solutions. A recovery study was performed at 0.5 mg/L concentration
in three replicates. The results are summarized in Table 3.
Amount of chromium
standard solution Concentration As seen in table, the recoveries are good, approximately
(5 mg/L) in 100 mL (mg/L) 105 percent. This demonstrates that the extraction is not
Blank – 0 causing transformation of the Cr(VI) spike to Cr(III).
Reference 1 2 mL 0.10
Reference 2 4 mL 0.20
Reference 3 6 mL 0.40
Reference 4 8 mL 0.60
Reference 5 10 mL 0.80
Reference 6 20 mL 1.00
2
10. Method detection limit: 10 replicate reagent blank solutions
Table 3. Replicate spike recoveries.
were prepared to make an estimate of method detection
Sample % Recovery limit. To determine method detection limit, seven replicate
Sample 1 104.8 aliquots of fortified reagent water (0.01 mg/L) were pre-
pared and processed through entire analytical method.
Sample 2 104.6
The method detection limit was calculated as follows,
Sample 3 104.6
MDL = (t) X (s) where,
t = student’s t value for a 99% confidence level and a
standard deviation estimate with n-1 degrees of freedom.
[t = 3.143 for seven replicates].
s = standard deviation of replicate analyses.
The method detection limit found to be 0.003 mg/L.
Sample analysis: Results obtained for different toy samples
are presented in Table 4. The yellow paint exceeds the limit
specified in the current standard for total chromium (60 mg/Kg).
The anticipated revision to the EU standard recommends a
limit of 0.02 mg/Kg hexavalent chromium in a dry, brittle or
pliable toy, much lower than the current standard and based
on the species. The detection limit measured here is sufficient
for the new regulatory level if a larger sample is taken for
extraction or a smaller dilution is used.
Table 4. Sample analysis results (calculations are based on total
amount extracted and dilution factor).
Sample Cr +6 – Total Chromium –
UV result (mg/Kg) ICP result (mg/Kg)
Yellow Plastic 5.4 29.9
Green Fabric ND 2.6
Blue Paint-1 7.2 89.5
Blue Paint-2 11 66.9
Yellow Paint-1 430 1790
Yellow Paint-2 360 1870
Red Paint-1 ND 58.4
Red Paint-2 ND 47.4
*ND: not detected
The total amount of chromium in the extracts was measured
using Inductively Coupled Plasma Optical Emission Spectroscopy
(ICP-OES) with resulting values in Table 4. Since the total
Figure 2. Calibration graph. chromium value is made up of both Cr(III) and Cr(VI) this is
a good indication of the maximum amount of Cr(VI) that
might be present. This provides an order-of-magnitude
confirmation of the analysis.
PaiNt-coateD toY GReeN FaBRic Yellow Plastic
Figure 3. Toy samples.
3
12. A P P L I C AT I O N N O T e
Liquid Chromatography
Author
Roberto Troiano, PerkinElmer
William Goodman, PerkinElmer
UHPLC seParation
and deteCtion of Introduction
BisPHenoL a (BPa) The BPA or bisphenol A (Figure 1) has become well know
over the past year as concerns for its effect on human health
in PLastiCs and well being have been raised. The concerns over BPA
began with baby bottles and spread to include other types of
bottles.
BPA is used in the production of two very common polymers PVC and Polycarbonate. PVC,
Polyvinyl chloride, is used in many different products including building materials, medical devices
and children’s toys. BPA is used in PVC production as a polymerization inhibitor, residual BPA may
remain after the polymerization is complete. Polycarbonate is another very commonly used plastic.
It has very desirable properties for both optical clarity and heat resistance. BPA is an important
monomer in the production of polycarbonate polymer, not all of the BPA is consumed in the pro-
duction and may leach out of the polymer. Recently, many applications of polycarbonate have been
replaced with new copolymers, such as co-polyester, to eliminate BPA.
Figure 1: Structure of Bisphenol A (BPA).
13. As a result of the health concerns over human exposure to BPA Results
this molecule is now monitored in specific products, including The BPA analyzed with the given LC conditions eluted at 5.43
baby bottles and other children’s products. Simple and robust mins (Figure 3). The UHPLC system was calibrated across a
test methods are needed to determine the presence and amount range of 1 – 50 ppb (µg/L) BPA (Table 2).
of BPA in plastic materials. This paper will present the extraction
and HPLC analysis of children’s products for BPA.
Figure 2: Children's toy samples analyzed for BPA in this application note.
Experimental
The study presented here includes extraction of BPA from a toy
matrix and analysis with UHPLC. The extraction procedure
Figure 3: BPA calibration standard at 1 ppb.
used here is intended to simulate the contact routes through
which children are likely to encounter BPA. Two different extrac-
tion techniques were used to analyze BPA in samples (30 g sam- Table 2: Table for the analysis of BPA across the range of 1 – 50 ppb (µg/L).
ple used for each extraction). The first extraction method Concentration Response
immersed the sample in 1 L of water, at 40 ˚C for 24 hours (EN
14372). The second immersed the sample with 1 L HCl (0.07 1 ppb 54163
M) at 10 ppb 378051
37 ˚C for 2 hours. Following extraction the samples were ana- 20 ppb 820335
lyzed with a PerkinElmer Flexar™ FX-10 UHPLC system includ-
ing a PerkinElmer Series 200a Fluorescence detector. The sepa- 40 ppb 1548750
ration was performed on a Brownlee Validated C8 Column (see 50 ppb 1957851
Table 1).
r2 0.9993
Table 1: HPLC Conditions for the Analysis of BPA
HPLC System PerkinElmer Flexar FX-10 UHPLC The limit of quantitation (LOQ) for BPA with the method pre-
Injection Volume 50 μL sented here is 1 ppb. The signal to noise at the LOQ is approxi-
mately 10:1. The response across the calibration range fit a linear
Column PerkinElmer C8 (150 mm x 4.6 mm, 5 μm)
calibration with an r2 value of 0.9993. Blanks analyzed between
Mobil Phase Methanol/Water (65/35) standards and samples showed the system was free from any BPA
Flow Rate 1 mL/min contamination or carryover.
Detector Wavelength Excitation – 275 nm / Emission – 313 nm BPA in the extracts of the toy samples were quantified using the
calibration curve generated during standard analysis (Table 3).
Detector Response Time 0.1 sec
Figure 4 shows the chromatogram of the water extract of the toy
PMT, Em BDW Super High, Wide dwarf sample.
Run Time 15 min
Table 3: Results from toy sample analysis.
Sample Extraction Type µg/L µg/g
Cube water 2.04 0.068
Cube HCl ND ND
Die water 3.35 0.111
Die HCl 1.56 0.052
Dwarf water 4.32 0.144
Dwarf HCl 1.78 0.059
2
15. applIcatIon note
Children's Products
authors
Zoe Grosser, ph.D.
laura thompson
lee Davidowski, ph.D.
PerkinElmer Inc.
Shelton, CT
Suzanne Moller
Innov-X Systems
Woburn, MA
Lead and Other Toxic Introduction
From 2007 to 2008, the number of recalls for toys exceed-
Metals in Toys Using ing the U.S. limits set for lead dropped 43%. This represents
however, more than 300,000 individual products posing
XRF Screening and potential hazardous exposure for children. The Consumer
Product Safety Improvement Act of 2008 (CPSIA 2008)
ICP-OES Quantitative defines a children’s product as a product primarily used by
Analysis a child under the age of 12 and defines new levels of lead
allowed in those products1. Allowable lead in painted
surfaces will be reduced from 600 mg/kg to 90 mg/kg one
year from enactment of the legislation (enactment date:
August 14, 2008). Allowable total lead content (surface and substrate) is reduced from 600 mg/kg
to 100 mg/kg, incrementally over the course of three years. The American Academy of Pediatrics
suggests that a level close to the background level in soil of 40 mg/kg would be most protective
of children’s health2.
Currently, EN-71, Part 3 and ASTM 963 specify evaluation of the toy by soaking in a mild hydrochloric
acid solution at body temperature and measuring the accessible metal extracted into the solution.
If a coating can be separated, a total analysis of the coating to comply with lead content
requirements can be done. CPSIA 2008 provides no exemption for electroplated substrates, so
that a total analysis on both coating and substrate must be done, though little other measurement
guidance is currently available. EN-71 may also be revised in the near future to add other hazard-
ous elements, such as aluminum, cobalt, copper, nickel, and others. The evolving need to measure
lead and other metals at increasingly lower levels makes information on analysis technologies
and performance valuable in making knowledgeable decisions.
16. A variety of techniques can be used to meet the regula- of children’s products, including toys that may require
tions, including atomic absorption (both flame FLAA analysis? This question is addressed in this work using
and graphite furnace GFAA), inductively coupled plasma ICP-OES and hand-held XRF to examine a variety of toy
optical emission spectroscopy (ICP-OES) and inductively materials. Ease of use and agreement between techniques
coupled plasma mass spectrometry (ICP-MS). Hand-held at the current level for lead were evaluated.
energy dispersive XRF, requiring minimal or no sample
preparation can provide a way to screen products on-site experimental
as to determine whether further quantitative analysis is A variety of children’s toys were obtained randomly from
required. a church nursery room and other sources. One known
recalled item, Boy Scout totem badges of differing ages
The techniques are compared for several parameters in
were also obtained. Figure 1 shows the variety of toys,
Table 1.
including fabric, soft and hard toys and some with painted
Since the techniques in Table 1 have different character- surfaces.
istics, which would be the most suitable for the variety
Table 1. Comparison of Several Analysis Techniques for Lead Determination (mg/kg).
GFAA ICP-OES ICP-MS Hand-held XRF
Estimated detection limit for lead* 0.025 0.5 0.025 NA**
Sample prep required Yes Yes Yes No
Simultaneous multielement No Yes Yes Yes
* Includes a 500x dilution to account for sample preparation for GFAA, ICP-OES, and ICP-MS. Detection limits can be further improved if a smaller dilution is used.
**NA: screening tool, detection limits matrix driven.
Table 2. Microwave Digestion Program.
Power (W) Ramp (min) Hold (min) Fan
500 5:00 15:00 1
900 10:00 15:00 1
0 20:00 2
Table 3. ICP-OES Instrumental Conditions.
Instrument Optima 7300 DV ICP-OES
RF Power 1450 W
Figure 1. Variety of toys measured.
Nebulizer Flow 0.55 L/min
Auxiliary Flow 0.2 L/min
Plasma Flow 15.0 L/min
Sample Pump Flow 1.2 mL/min
Plasma Viewing Axial
Processing Mode Area
Auto Integration 5 sec min-20 sec max
Read Delay 30 sec
Rinse 30 sec
Replicates 3
Background Correction one or two points
Spray Chamber Cyclonic
Nebulizer SeaSpray (Glass Expansion®, Pocasset, MA)
Figure 2. XRF result screen.
2
17. Samples were prepared for ICP-OES analysis by scraping elements over a wide dynamic concentration range, from
off the paint or cutting the substrate into small pieces. ppm levels up to virtually 100% by weight. An example
Approximately 0.01-0.1 g was weighed into a Teflon® of the result obtained on the screen is shown in Figure 2.
microwave digestion vessel and 6 mL of concentrated
nitric acid (GFS Chemical®, Columbus, Ohio) and 1 mL Results and Discussion
of concentrated hydrochloric acid (GFS Chemical®, The analysis of the toys by hand-held XRF and ICP-OES
Columbus, Ohio) were added. The samples were placed are shown in Table 4. The check mark in the XRF column
in the Multiwave™ 3000 microwave digestion system indicates the XRF analysis displayed a lead value higher
(PerkinElmer, Shelton, Connecticut) and digested than the limit of 600 mg/kg in the screened toy indicating
according to the program shown in Table 2. further quantitative analysis is recommended. The value
determined by ICP-OES confirms that the value was
The Optima™ 7300 DV was used for analysis of the full
higher than the regulatory limit in the coating or for a
suite of elements currently regulated in EN-71, Part 33
total analysis of the substrate material. In this case, the
and referenced in ASTM D9634, and CPSIA, including
value measured with XRF is not reported although the
lead. The conditions are as shown in Table 3.
value would give further refinement of the concentration
The Innov-X® Import Guard model was used for all hand- for the elements measured.
held XRF measurements, and a general calibration was
Detection limits for the ICP-OES are shown in Table 5 for
performed. For analysis of the same samples with XRF,
no sample preparation was required. The system uses both the digested solution and the amount in the origi-
energy dispersive X-ray fluorescence and easily identifies nal material. Since the amount taken for digestion may
vary and the dilution can be changed, a 500x dilution
was assumed for the calculation. This represents a typical
0.1 g of material diluted to a final volume of 50 mL.
Duplicate sample preparation and analysis of several
samples can indicate the reproducibility of the method,
provided the samples are homogeneous. Table 6 shows
the results for duplicate sample preparation and analysis
of three different types of samples. The fabric and the
uniformly-colored plastic show good agreement between
the duplicate analyses (less than 20% relative percent
difference). The puzzle board required scraping paint
from the surface for analysis and it was difficult to uni-
formly remove only the paint without taking some of the
substrate, as shown in Figure 3. This may contribute to
Figure 3. Puzzle board and scrapings. the very different values obtained for the duplicate analysis.
Table 4. Results for Toys Measured with XRF and ICP-OES (mg/kg).
XRF Antimony Arsenic Barium Cadmium Chromium Lead Mercury Selenium
Toy Stove Knob √ 32 <DL 2 4 773 3950 <DL 13
Yellow Mega Block √ 12 <DL 56 3 774 3690 <DL 27
Badge-1 New (Yellow Paint) √ <DL <DL 16900 14 7340 34500 <DL 85
Badge-2 Older (Yellow Paint) √ <DL <DL 21200 2 8870 42100 <DL 20
Yellow Baby Rattle √ <DL <DL 70 <DL 544 2970 <DL 8
Yellow Crib Toy Holder Strap √ 15 <DL 146 <DL 377 1900 <DL <DL
Green Cup <DL <DL 3220 2260 4 17 <DL 6
Red Ring <DL <DL 91 4 3 15 <DL 8
3
18. Table 5. Estimated Detection Limits.
Element Detection Limit Detection Limit
in Solution (mg/L) in Solid (mg/kg)
Antimony (271 nm) 0.008 3.8
Arsenic (189 nm) 0.002 1.2
Barium (233 nm) 0.004 1.9
Cadmium (228 nm) 0.002 1.1
Chromium (267 nm) 0.003 1.6
Lead (220 nm) 0.010 6.4
Mercury (254 nm) 0.005 2.2
Selenium (196 nm) 0.011 5.7 Figure 4. Yellow ball measured in replicate.
Table 6. Duplicate Sample Preparation and Analysis (mg/kg).
Antimony Arsenic Barium Cadmium Chromium Lead Mercury Selenium
Green Fabric 15 <DL 302 <DL 332 1780 <DL <DL
Green Fabric -Duplicate 13 <DL 329 <DL 362 1940 <DL <DL
Puzzle Board 919 <DL 14 4 21,200 121,000 <DL 49
Puzzle Board - Duplicate 2187 <DL 5 5 14,600 82,600 <DL 15
Yellow Handle <DL <DL 360 <DL 1310 4990 <DL <DL
Yellow Handle - Duplicate <DL <DL 336 <DL 1200 4620 <DL 12
A more extensive analysis of reproducibility is shown in Table 8 shows an example for a hydrochloric acid extract
Table 7. The standard deviation of five separate digestions from a toy, extracted and measured using procedures
and analyses for a yellow ball (Figure 4) show excellent specified in EN-71, Part 3. Both the original set of ele-
precision. ments reported and the elements determined later (in
blue) by reprocessing the data to examine the informa-
It is interesting to note the lead level is high, in agreement
tion previously stored for those elements are listed. This
with the XRF analysis. Several other elements, such as
can be useful in assessing samples that may have been dis-
chromium, are also high. The XRF value reported for
posed or in better understanding the scope of samples in
lead in the ball was 3940 mg/kg.
preparing for future analyses.
Regulations are continually changing and may require
different elements to be monitored in the future, at dif-
ferent concentration levels. One way to help in preparing
for that eventuality is the use of the universal data acqui- Table 7. Analysis of Five Replicate Samples of a Yellow
Ball.
sition (UDA) feature, exclusive to the Optima ICP-OES
software. In this case the Optima ICP-OES collects data Element Average (mg/kg) SD
for all of the wavelengths all of the time. If a standard Antimony (271 nm) 10.6 0.49
is run at the time of the original data acquisition that Arsenic (189 nm) 12.4 1.8
includes more elements than the elements of interest Barium (233 nm) 707 3.1
at that moment, other elements can be measured with Cadmium (228 nm) 78.3 0.73
good quantitative accuracy by reprocessing at a later Chromium (267 nm) 414 2.3
date. If an elemental concentration is of interest for an Lead (220 nm) 1980 9.7
element that was not included in any of the usual multi- Selenium (196 nm) 16.3 1.3
element standards, reprocessing can provide a semiquan-
Mercury (254 nm) <DL –
titative result, usually within ±30% of the true value.
4
20. a p p l i c at i o n n o t e
ICP-OES
Authors
Paul Krampitz
Stan Smith
PerkinElmer, Inc.
Shelton, CT 06484 USA
Increased Laboratory Abstract
The use of an ESI SC FAST autosampler
Productivity for ICP- coupled to a Perkin Elmer Optima 7300
DV ICP can dramatically improve produc-
OES Applied to U.S. tivity for the analysis of environmental
EPA Method 6010C samples using EPA SW-846 Method
6010C. Sample throughput, as determined
by sample-to-sample run time can be
improved by as much as 100% as compared
to traditional sample introduction systems and autosampler configurations. Both
sample analysis time and rinse out time are significantly reduced, allowing for a
doubling of overall productivity. In addition, stability of the plasma and instrument
is very robust allowing for long, unattended run times while meeting calibration and
method QC requirements. Valuable man hours spent on instrument maintenance
and recalibration are reduced. This paper will demonstrate that these productivity
enhancement claims can be accomplished for implementation SW-846 Method 6010C.
21. Introduction The analytical test methods found in SW-846 are commonly
Since 1980, the EPA has maintained a publication entitled used by laboratories for the analysis of a wide range of sample
SW-846 Test Methods for Evaluating Solid Waste, Physical/ matrices including, but not limited to: groundwater, surface
Chemical Methods, more commonly referred to simply water, leachates, soils, and a whole host of other solid and
as SW-846. Currently, SW-846 is in its third edition and liquid wastes, both organic and aqueous. The RCRA regulatory
includes several updates. Since the third edition was programs for which SW-846 is most commonly used can be
released in 1986, there have been 9 updates (Updates I, II, found in the U.S. Code of Federal Regulations (CFR), specifically
IIA, IIB, III, IIIA, IIIB, IVA, and IVB), the most recent of which Title 40 CFR Parts 122-270. One of the methods found in
was dated February, 2007. Included in SW-846 are over 200 SW-846 that is commonly used by most environmental labora-
documents related to quality control practices, analytical tories for the analyses of elements in environmental samples
test methods, sampling methods, and other topics related is 6010C Inductively Coupled Plasma-Atomic Emission
to the United States Environmental Protection Agency (EPA) Spectrometry (ICP-AES).
Resource Conservation and Recovery Act (RCRA). Essentially,
Method 6010C is the fourth version of this method and was
SW-846 is the official compendium of analytical and sam-
released as part of SW-846 Update IV in February, 2007. As
pling methods that have been evaluated and approved by
indicated in the method, all samples other than filtered, pre-
the EPA for use in complying with RCRA regulations.
served groundwaters require acid digestion prior to analysis.
As indicated by the EPA, the analytical methods in SW-846 There are more than 8 acid digestion methods applicable to
are intended to be guidance documents and are not intended ICP-AES found in SW-846 and some of those that are commonly
to be overly prescriptive except in the cases where a particular used for the preparation of environmental samples include:
analyte or parameter is considered method defined. Such
• 3005A Acid Digestion of Waters for Total Recoverable or
method-defined parameters are where the analytical result is
Dissolved Metals for Analysis by FLAA or ICP Spectroscopy
wholly dependent on the process and conditions of the test or
preparation method such as the Toxicity Characteristic Leaching • 3010A Acid Digestion of Aqueous Samples and Extracts
Procedure (TCLP), Method 1311, where the conditions specified for Total Metals for Analysis by FLAA or ICP Spectroscopy
in the method directly affect the concentration of analytes
extracted into the leaching solution. However, despite this clear • 3015A Microwave Assisted Acid Digestion of Aqueous
indication from the EPA that SW-846 methods are intended as Samples and Extracts
guidance documents, many regulatory agencies invoke these
• 3050B Acid Digestion of Sediments, Sludges, and Soils
methods with no permissible changes or modifications.
• 3051A Microwave Assisted Acid Digestion of Sediments,
Sludges, Soils, and Oils
Summary of Method
Method 6010C is a general analytical method that is applicable
to a wide variety of liquid and solid samples and that provides
specific procedures and references for sample collection,
preservation, and preparation (i.e., acid digestion), in addition
to recommended instrument procedures for calibration,
detection limits, and interference correction. In addition,
SW-846 6010C also contains procedures for the preparation,
analysis, and acceptance limits for quality control samples
needed for each batch of samples to be analyzed. While
the method is intended only as a guidance document and is
subject to interpretation and modification, implementation
of the QC criteria as stated in the method was followed for
Figure 1. Schematic of FAST sample introduction system coupled to an Optima
the work performed and summarized in this paper. The EPA
7300 DV ICP spectrometer.
has approved this method for the analysis of 31 elements
and Table I includes all the elements analyzed and their
associated wavelengths. Following is a summary of the
procedure from SW-846 6010C as performed in this work.
2
22. Summary of Method 6010C
Table I. Wavelengths Monitored and Viewing Modes Used for
SW-846 6010C. Establish Initial Demonstration of Performance
Wavelength 1. Perform Instrument Detection Limits (IDL)
Analyte Symbol Monitored (nm) View 2. Determine Linear Dynamic Range (LDR)
Aluminum Al 308.215 Radial a. Recovery of elements must be ±10% of the known
Antimony Sb 206.836 Axial values for each element
Arsenic As 188.979 Axial 3. Determine whether interelement corrections are needed by
Barium Ba 233.527 Axial analysis of an Interference Check Solution (ICS)
Beryllium Be 234.861 Radial Routine Analysis
Boron B 249.677 Radial 1. Light plasma and warm up instrument, allow
Cadmium Cd 226.502 Axial 15-30 minutes
Calcium Ca 315.887 Radial 2. Optimize instrument and plasma conditions per instrument
Chromium Cr 267.716 Axial manufacturer
3. Calibrate ICP using blank and minimum of one standard
Cobalt Co 228.616 Axial
a. Rinse with blank between each standard
Copper Cu 327.393 Axial
b. Use the average of multiple readings (3 replicates in
Iron Fe 238.204 Radial
this study) for all standards and samples
Lead Pb 220.353 Axial
4. Verify calibration by analyzing the Initial Calibration Verification
Lithium Li 670.784 Radial (ICV) standard
Magnesium Mg 285.213 Radial a. ICV standard must be from a separate source as used for
Manganese Mn 257.610 Axial calibration standards
Molybdenum Mo 202.035 Axial b. Recovery of elements must be ±10% of the known values
for each element
Nickel Ni 231.604 Axial
5. Verify the lowest quantification limit by analyzing the Lower
Phosphorus P 213.617 Axial Limit of Quantitation Check Sample (LLQC)
Potassium K 766.490 Radial a. LLQC standard should be from the same source as the
Selenium Se 196.026 Axial calibration standards
Silicon Si 251.611 Radial b. Recovery of elements must be ±30% of the known
Silver Ag 328.068 Axial values for each element
6. Analyze the Initial Calibration Blank (ICB)
Sodium Na 589.592 Radial
a. Target elements should not be detected at or above the
Strontium Sr 407.771 Radial
Lower Limit of Quantitation
Thallium Tl 190.801 Axial
7. Analyze test samples along with appropriate batch quality
Tin Sn 189.927 Axial control samples
Titanium Ti 334.940 Axial 8. After every 10 samples, verify calibration by analyzing the
Vanadium V 292.402 Axial Continuing Calibration Verification (CCV) standard
Zinc Zn 206.200 Axial a. CCV standard should be from the same source as the
calibration standards
Internal Standards
b. Recovery of elements must be ±10% of the known values
Yttrium Y 371.029 Radial/Axial
for each element
Tellurium Te 214.281 Radial/Axial
9. Immediately following the analysis of each CCV, analyze the
Continuing Calibration Blank (CCB)
a. Target elements should not be detected at or above the
Lower Limit of Quantitation
10. The LLCCV must be analyzed at the end of each analytical
batch but is also recommended to be analyzed after every 10
samples
a. Recovery of elements must be ±30% of the known values
for each element
11. At the end of the run, analyze the CCV and CCB
a. Acceptance limits are the same as in steps 8 and 9
3
23. Batch Quality Control Samples Initial Performance Demonstration
1. Analyze the Method Blank
Instrument Detection Limits
a. Target elements should not be detected at or above
The Instrument Detection Limits (IDL) for all elements were
10% of the Lower Limit of Quantitation
determined using a reagent blank solution according the
2. Analyze the Laboratory Control Sample (LCS) procedures in Section 9.3 of SW-846 6010C. Specifically, a
a. Recovery of elements must be ±20% of the spiked reagent blank was analyzed seven consecutive times, with
values for each element routine rinsing procedures between each analysis, for all ele-
ments three times on non-consecutive days. The IDLs were
3. Analyze the Matrix Spike
then estimated by calculating the average of each element’s
a. Recovery of elements must be ±25% of the spiked standard deviation. The obtained IDLs are presented in Table III.
values for each element
Evaluation of Interferences
4. Analyze the Sample Duplicate or Matrix Spike Duplicate
Interferences were evaluated according to Section 4.2.10 of
a. The precision criterion for duplicates is a relative
Method 6010C. An interference check solution containing
percent difference of no greater than 20%
500 mg/L of Al, Ca, Mg, Na, 200 mg/L of Fe and 50 mg/L of
K was used for evaluation.
Experimental
Instrument
Table II. FAST-Optima 7300 DV Instrumental Conditions and
An Optima 7300 DV (PerkinElmer, Shelton, CT) was used
Experimental Parameters.
in conjunction with an SC-FAST (Elemental Scientific Inc.,
Optima 7300 DV Parameters
Omaha, NE) for the analysis of all samples described in this
work. The FAST sample introduction system is controlled RF Power 1450 watts
through the Optima WinLab32™ software and a schematic Plasma Gas Flow 15 L/min
of the FAST is shown in Figure 1. The elements, wavelengths, Auxiliary Gas Flow 0.2 L/min
and plasma viewing modes used are listed in Table I. The Nebulizer Gas Flow 0.6 L/min
instrument conditions for both the Optima ICP-OES and the Peristaltic Pump Speed 0.85 mL/min
SC-FAST as well as the experimental parameters used are Nebulizer/Spray Chamber Sea Spray/Glass cyclonic
provided in Table II.
Torch Cassette Position -3
Standards Purge Normal
Resolution Normal
All calibration standards and non-sample solutions were
prepared with ASTM Type I (i.e., >18MΩ-cm) deionized Integration Time 2 s min/5 s max
water and trace metals grade or better nitric acid. Read Delay 14 s
Wash Time 1s
Internal Standards Number of Replicates 3
All samples were spiked with 1.5 mg/L of yttrium and 2.5 mg/L FAST Parameters
of tellurium. The spiking solution was made from 1000 mg/L Sample Loop Volume 2 mL
single element stock solutions. Sample Loop Fill Rate 27 mL/min
Calibration Carrier Pump Tubing Black/Black (0.76 mm i.d.)
Sample Load Time 7s
The calibration blank and standards were prepared in 1%
Rinse 1s
nitric acid. Calibration was performed using a calibration
blank and a single standard containing all elements at 1 mg/L. Analysis Time (total) 75 s (sample-to-sample)
The calibration standard was prepared from a combination Experimental Parameters
of single element and multi-element stock solutions, all Carrier Solution 1% HNO3 plus 0.05% surfactant
containing elements at 1000 mg/L. Rinse Solution 1% HNO3
Acidity of Stds/Samples 1% HNO3
Monitored Wavelengths
As previously mentioned, the monitored elements, wavelengths,
and plasma viewing modes used are listed in Table I.
4
24. Linear Range
Table III. Instrument Detection Limit (IDL) Data and Linear Dynamic Ranges (LDR).
Analyte Wavelength IDL IDL IDL 6010C, LDR, The Linear Dynamic Range (LDR) was
RUN 1 RUN 2 RUN 3 IDL, ug/L mg/L determined for each element and met
the criterion in Section 10.4 of SW-846
Ag 328.068 0.159 0.103 0.172 0.14 100
6010C as found in Table III. That is, the
Al 308.215 1.732 0.630 1.898 1.42 2000
upper linear range was established by
As 188.979 0.349 0.415 0.774 0.51 100
analyzing standards against the same
B 249.677 4.504 1.400 1.109 2.34 2000 calibration used for analyzing samples and
Ba 233.527 0.056 0.016 0.034 0.04 25 obtaining recoveries within ±10% of the
Be 234.861 0.034 0.018 0.075 0.04 50 known concentration value. The Lower
Ca 317.933 0.544 0.550 0.783 0.63 900 Limit of Quantitation was confirmed
Cd 226.502 0.041 0.037 0.073 0.05 100 through the analysis of the Lower Level
Co 228.616 0.076 0.092 0.078 0.08 250 Check Standard (LLICV and LLCCV) and
obtaining recoveries within ±30% of the
Cr 267.716 0.086 0.099 0.071 0.09 100
known concentration value. The LLICV
Cu 327.393 0.062 0.047 0.158 0.09 300
and LLCCV were run at a concentration
Fe 259.939 0.256 0.230 0.168 0.22 400
of 500 ug/L for this study.
K 766.49 7.269 5.270 5.499 6.01(0.24) 2000
Mg 279.077 1.763 2.030 3.108 2.30 700 Memory Effects
Mn 257.61 0.005 0.009 0.018 0.01 40 Memory effect studies were performed
Mo 202.031 0.132 0.097 0.180 0.14 125 to obtain the rinse time needed between
Na 589.592 1.147 2.364 1.609 1.71(0.2) 900 sample measurements using the ESI FAST
Ni 231.604 0.178 0.188 0.161 0.18 125 system. The elements studied were the
most likely elements to be high for envi-
Pb 220.353 0.427 0.229 0.368 0.34 100
ronmental samples run under SW 846:
P 213.617 1.543 1.091 1.249 1.29 3000
Al, Ca, Fe, K, Mg, and Na. All of the data
Li 670.784 0.214 0.176 0.364 0.25(0.03) 200
can be found in Figure 2. Five blanks were
Sb 206.836 0.662 0.586 0.226 0.49 100 run, then five standards, then five blanks
Se 196.026 0.875 0.953 0.485 0.77 100 again to obtain the rinse out profiles.
Si 251.611 2.546 0.569 1.080 1.40 2500 Al, Ca, Mg, and Na were run at 500 mg/L.
Sr 421.552 0.025 0.029 1.139 0.40(0.01) 50 Fe was run at 200 mg/L and K was run at
Sn 189.927 1.928 1.218 0.095 1.08(0.35) 2000 50 mg/L. The FAST parameters used were
Ti 334.94 0.017 0.018 1.863 0.63 50 the same as listed in Table II above.
Tl 190.801 0.574 0.568 0.114 0.42 100
V 292.402 0.070 0.059 0.781 0.30 50
Zn 206.2 0.051 0.039 0.086 0.06 100
( ) = Axial
5
25. Figure 2. Above figures show the rinse out time using the ESI FAST system. Al, Ca, Mg, and Na were run at 500 mg/L. Fe was run at 200 mg/L and K was run at
50 mg/L. Samples were rinsed out to near baseline in 7 seconds.
Quality Control and Sample Analysis samples analyzed were synthetic or natural water samples
The accuracy and precision of the implementation of with no detectable turbidity or suspended solids, no acid
Method 6010C was demonstrated through the analysis digestion procedures were performed. The batch QC consisted
of several reference materials and a local filtered, treated of a method blank, a sample duplicate (DUP), a Laboratory
surface water sample (Lake Michigan). The quality control Control Sample (LCS), a Matrix Spike (MS), and a Matrix
procedures specified in SW-846 were followed throughout Spike Duplicate (MSD). A natural surface water sample was
the work performed. Immediately following calibration, used to prepare the DUP, MS, and MSD. Results of all batch
the ICV (second source), LLICV, and ICB were analyzed and QC samples were found to be within method-specified criteria.
all results were determined to be within method-specified That is, no elements were detected within 10% of the
criteria, ±10%, ±30%, and <LLQC respectively. Following LLQC, all elements detected in the sample and the sample
the analysis of each sequence of ten samples, the CCV, DUP above the LLQC had relative percent differences of less
LLCCV, and CCB were analyzed and found to be within the than 20, all elements in the LCS were recovered within 20%
method-specified criteria (same as for ICV, LLICV, and ICB). of the known spike concentration, all elements in both the
In additional to the sequential run QC (10% frequency), MS and MSD recovered within 25% of the known spike
batch QC samples were also prepared and analyzed. As all concentration, and all spiked elements in the MS and MSD
had relative percent differences of less than 20.
6