United States
                  Environmental Protection
                  Agency
Environmental Monitoring
Systems Laboratory
Las Vegas NV 89193-3478
                  Research and Development
EPA/600/S4-88/012  Apr. 1988
4>EPA         Project Summary
                 A Single-Laboratory
                 Evaluation  of SW-846  Methods
                 7090/7091  Determination of
                 Beryllium by Flame  and
                 Furnace Atomic Absorption
                 Spectrophotometry

                 Vernon F. Hodge, Daniel A. Darby, Wendy E. Thompson, and Clifton L. Jones
                   The results of a single-laboratory
                  study of the SW-846 Method 70907
                  7091 — "Determination of Beryllium
                  by Flame and Furnace Atomic Absorp-
                  tion  Spectrophotometry" are  de-
                  scribed. This study examined the appli-
                  cation of these two powerful beryllium
                  detection methods to the analysis of
                  selected liquid and solid samples after
                  digestion  by appropriate SW-846
                  methods. Method performance data,
                  including:  detection limits, optimum
                  concentration ranges (linearity), spike
                  recoveries, interferences,  precision,
                  accuracy,  and optimum instrument
                  operating  parameters, are presented
                  and discussed.
                   This Project Summary was devel-
                  oped by EPA's Environmental Monitor-
                  ing Systems Laboratory, Las Vegas,
                  NV, to  announce key findings of the
                  research project that is fully docu-
                  mented in a separate report of the same
                  title  (see  Project Report ordering
                  information at back).
                  Introduction
                   The  single-laboratory evaluation of
                  SW-846 Methods 7090/7091 for the
                  determination of beryllium by flame and
                  furnace atomic absorption Spectropho-
                  tometry (AAS) was undertaken in order
                  to obtain method-performance data and
                  to augment existing data. The  method-
                  performance parameters studied were:
 1.  Detection Limits
 2.  Optimum Concentration Ranges
    (Linearity)
 3.  Spike Recoveries
 4.  Interferences
 5.  Precision
 6.  Accuracy
 7.  Ruggedness Testing

  All data were collected according to the
procedures described in "Guidelines for
Selection and Validation of U.S. EPAs
Measurement Methods" (Draft, January
30, 1986) and "Test Methods for  Eva-
luating Solid Waste," SW-846 (Third
Edition, November 1986).
  Method  7090 and Method 7091 are
measurement procedures for the deter-
mination of beryllium in solution. There-
fore, solid waste samples, and most
aqueous samples, require digestion prior
to analysis. Twelve performance evalua-
tion or target samples were chosen for
this  study. Five  of  these were liquid
samples,  two of which were U.S.
National Bureau of Standards—Standard
Reference Materials(NBS-SRMS). There
were seven solid samples of which two
were  NBS-SRMS, two were  Certified
Reference Materials from Canada  (one
from the  National  Research  Council,
Ottawa, and  one from the Centre for
Mineral and Energy Technology, Ottawa)

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and  one solid  was  a  U.S.  EPA-CLP
Reference  Material  prepared  by the
UNLV-QAL. The liquid  samples to be
analyzed by flame AAS (Method 7090)
were digested  according to Method
3010,  and the liquid  samples to be
analyzed by furnace AAS (Method 7091)
were digested  according to Method
3020. All solid  samples were digested
by Method 3050 prior to analyses.
  Instrument  detection  limits and the
optimum concentration ranges  were
determined in  aqueous samples  that
were free from  interferences. Method-
detection limits, spike recoveries, preci-
sion, and accuracy were determined in
digests of each of the 12 target samples.
The stability of beryllium in the sample
digests was monitored for 30 days.
  A  survey of  the literature revealed
several reports of elements  whose
presence in solutions containing beryl-
lium, caused increased or decreased
absorbance, thereby giving erroneously
high or low concentration measurements
for beryllium. Therefore, the  individual
effects of Al,  Mg, and Si on  the deter-
mination of beryllium  by flame AAS
(Method 7090) and of Al, Ca, Ce, Cr, La,
Mg,  Mn, Mo,  Si, Sr, H2S04, W, and Fe
by furnace AAS (Method 7091)  were
investigated. Several  chemicals includ-
ing hydrofluoric acid, 8-hydroxyquinoline
and  lanthanum  were reported to  elim-
inate some of  the  interferences. The
usefulness  of these additives was also
investigated.

Conclusions
  The  single-laboratory evaluation of
Method 7090 and Method 7091  demon-
strates that the methods are sensitive,
precise, and accurate for the quantifica-
tion of beryllium in a variety of solutions.
The  solutions targeted by  this  study
included acid  digests  of liquid and solid
samples according to  SW-846 digestion
Method 3010, Method 3020, and Method
3050.  The performance parameters
determined in this study for the two
methods are summarized below.

Determination of Beryllium by
Acetylene/Nitrous Oxide
Flame Atomic Absorption
Spectrophotometry (Method
7090)
  The instrument detection limit (IDL) for
the determination of beryllium by flame
AAS in a matrix free from interferences
was found to  be 0.003 mg/L. The
optimum concentration  range, also in  a
matrix free  from interferences, was
found to be 0.01 mg/L to 2.6 mg/L.
  The analysis of the 12 liquid and solid
samples that were digested by Method
3010 or Method 3050 yielded a method
detection limit (based on 1 -g/100 mL for
solids) of 0.005 mg/L, or, two times the
IDL  (Table 1). The percent  relative
standard deviation (%RSD) was used as
a measure of the precision of the method,
and it ranged from about five percent at
0.02 mg/L to less than one percent at
0.75 mg/L. Recoveries of  predigestion
spikes of beryllium at  0.25 mg/L and
0.50  mg/L averaged  89   percent (99
percent with the addition of 0.1 percent
hydrofluoric acid (Table 2).
  Aluminum was found to be the only
element, of the  five investigated, that
interfered with  the determination of
beryllium (40 percent depression of
absorbance at 1000 mg/L  and 54 per-
cent at 5000 mg/L). The addition of 0.1
percent  hydrofluoric acid or 2.5 percent
8-hydroxyquinoline were  found  to  be
effective in eliminating this interference
for concentrations of aluminum up to
1000 mg/L. The addition of 0.3 percent
hydrofluoric acid was effective in elim-
inating the interference of aluminum at
5000 mg/L. By using modern instrumen-
tation, high concentrations of Mg and Si
(up to 5000 mg/L) did not interfere with
the determination of beryllium as cur-
rently stated in Method 7090.
  The accuracy  of Method 7090 was
evaluated by determining the beryllium
concentration  in  three NBS-SRMs,
before and after digestion by SW-846
methods, with excellent results.

Determination of Beryllium by
Furnace Atomic Absorption
Spectrophotometry (Method
7091)
  The  instrument  detection  limit  for
beryllium in a matrix free from interfer-
ences was found to be 0.08 /Jg/L (Table
3). The optimum concentration  range,
also in a matrix free from interferences,
was found to be from 0.01 /jg/L to 16
  The analysis  of  12  liquid  and solid
samples, which were digested by Method
3020 or Method 3050,  yielded a method
detection limit of 0.08 fjg/L,  the value
of which is the same as the instrument
detection  limit, demonstrating  that a
variety of matrices had little or no effect
on the detection of beryllium. The percent
RSD was  used as  a  measure  of  the
precision and ranged from an average of
7 perce nt at conce ntrations below 3 //g/L
to an average of 2.3 percent at concen-
trations  above  3  jug/L.  Recoveries of
predigestion spikes of  beryllium at  2.5
ug/L and 5.0 //g/L averaged 93 percent.
  A literature survey suggested that the
presence of any one of 12 elements  can
enhance or  depress the  absorbance of
beryllium in the furnace analysis. How-
ever, it was  found that when  peak area
was used to calculate the concentration
Table  1.   Method Detection Limit for the Determination of Beryllium by Flame Atomic
          Absorption Spectrophotometry, Method 7090
Matrix
Trace Elements in Water
Beryllium Spectrometric Solution
Synthetic Interference Solution
Natural Waste Water
TCLP Extract of Hazardous Waste
Coal Fly Ash
Municipal Digested Sludge
Three Kids Mine Material
Marine Sediment
Mineral Sample
Hazardous Waste Site Soil
Copper-Beryllium Alloy
Average
Slope'
0.92
0.90
0.54
0.90
0.94
0.77
0.73
0.64
0.74
0.68
0.73
0.90
0.78
MDL (ug/L)'
4.4
4.4
7.4
4.5
4.0
5.2
5.4
6.3
5.4
5.9
5.5
4.4
5.2
aThe method detection limit is defined by MDL = 3 Sa/m, where SB is the standard deviation
 of the instrument background signal and m is the slope of the calibration line in the sample
 matrix.

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T»ble 2.    Predigestion Spike Recoveries of Beryllium Determined by Flame Atomic Absorption
           Spectrophotometry, Method 7090, After Digestion of Liquids by Method 3010 and
           Solids by Method 3050

Trace Elements in Water

Beryllium Spectrometric
Solution

Synthetic Interference Solution
Natural Waste Water

TCLP Extract of Hazardous
Waste

Coal Fly Ash
Municipal Digested Sludge
Three Kids Mine Material

Marine Sediment

Mineral Sample
Hazardous Waste Soil

Copper-Beryllium Alloy
Be Added
(mg/L)
0.250
0.500
0.250
0.500
0.250
0.500
0.250
0.500
0.250

0.500
0.250
0.500
0.250
0.500
0.250
0.500
0.250
0.500
0.250
0.500
0.250
0.500
0.500
1.000
Percent
Recovery
Without HF
112
106
104
106
78
87
67
106
101

95
97
87
86
83
78
74
85
82
78
79
85
83
98
96
Percent
Recovery
With HF'
109
103
106
105
104
104
105
106
—

—
98
96
85
82
101
97
98
97
89
87
103
101
99
96
'With the addition ofO. 1 percent HF.
 Table 3.
Matrix
Method Detection Limit for the Determination of Beryllium by Furnace Atomic
Absorption Spectrophotometry. Method 7091
Slope'
                                                         MDL(ug/L)B
 Trace Elements in Water
 Beryllium Spectrometric Solution
 Synthetic Interference Solution
 Natural Waste Water
 TCLP Extract of Hazardous Waste
 Coal Fly Ash

 Municipal Digested Sludge
 Three Kids Mine Material
 Marine Sediment
 Mineral Sample

Hazardous Waste Site Soil
Copper-Beryllium Alloy

Average
                                  0.99
                                  0.95
                                  1.01
                                  1.06
                                  1.08
                                  0.99

                                  0.93
                                  0.96
                                  0.94
                                  0.97

                                  0.94
                                  0.85
                                  0.97
                          0.08

                          0.08
                          0.08
                          0.08
                          0.07
                          0.08

                          0.09
                          0.08
                          0.08
                          0.08

                          0.09
                          0.09
                          0.08
*The method detection limit is defined by MDL = 3 SB/rn, where SB is the standard deviation
 of the instrument background signal and m is the slope of the calibration line in the sample
 matrix.
of beryllium in  the  presence of these
elements, only molybdenum interfered
with  the determination  of beryllium
(Table 4). The presence of 1000 mg/L
molybdenum enhanced the peak area of
a  5  /ug/L solution of beryllium by 20
percent.
  The accuracy of Method 7091  was
evaluated by determining the concentra-
tion  of beryllium  in  three NBS-SRMS
before and  after digestion by SW-846
Methods, with excellent results.

Recommendations
  The following recommendations are
listed by method, with section references
made to the method as written in SW-
846.


Method 7090

3.0 Interferences
  3.2  This section  states that  "Back-
ground correction  may be required. . ."
This statement should be modified to
read "Background correction is required.

  3.3  This section warnsthat "Concen-
trations of aluminum greater than 500
ppm  may  suppress  beryllium  absor-
bance." This  statement should be
modifed to read  "Concentrations  of
aluminum greater than  700 mg/L will
suppress  beryllium  absorbance." The
addition of 0.1 percent hydrofluoric acid
was found to be effective in eliminating
this interference as stated in the current
version of the  method. However, this
study  demonstrated  that 0.3 percent
hydrofluoric acid is required for  alumi-
num concentrations  greater than 1000
mg/L.
  With regard to the statement, "High
concentration of magnesium and silicon.
. ." no evidence was obtained to corrob-
orate this  statement; no significant
interferences from Mg or Si at concen-
trations up to 5000 mg/L were observed
in  this single-laboratory  study using
modern instrumentation. Therefore, it is
recommended  that  this sentence be
deleted.

9.0 Method Performance
  9.1   While the  results of this study
yielded somewhat different values for the
optimum concentration range and detec-
tion limit, the values currently cited in
Method 7090 are near the experimental
levels found in this study. Therefore, no
changes are  recommended  for  this
section.

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 Table 4.   Effect of Aluminum, Calcium, Cerium,Chromium, Lanthanum, Magnesium, Manganese, Molybdenum, Silicon, Strontium, Sulluric
           Acid, Tungsten, and Iron on the Observed Absorbance of Beryllium in Furnace Atomic Absorption Spectrophotometry, Method
           7091
Interfering
Element
Img/L) Al Ca Ce
Observed Be Absorbance
Cr La Mg
in Presnce
Mn
of these Chemicals"
Mo Si Sr HiS
?O4 W Fe
Peak Area
     0
    100
   500
   1000
   5000

Peak Height
0.427
0.424
0.444
0.421
0.400
0.427
0.452
0.430
0.423
0.452
0.427
0.430
0.430
0.406
0.388
0.427
0.419
0.414
0.408
0.387
0.427
0.457
0.449
0.443
0.438
0.427
0.470
0.475
0.468
0.484
0.427
0.458
0.464
0.466
0.467
0.427
0.431
0.467
0.513
0.805
0.427
0.434
0.437
0.435
0.408
0.427
0.460
0.450
0.445
0.448
0.427
0.446
0.428
0.432
0.427
0.427
0.370
0.363
0.343
0.330
0.427
0.435
0.427
0.433
0.430
0
100
500
1000
5000
0.427
0.398
0.498
0.474
0.479
0.427
0.524
0.719
0.755
1.074
0.427
0.432
0.517
0.657
0.551
0.427
0.445
0.578
0.587
0.495
0.427
0.476
0.722
0.901
0.621
0.427
0.620
0.846
0.841
0.715
0.427
0.465
0.452
0.455
0.703
0.427
0.431
0.465
0.504
0.777
0.427
0.433
0.442
0.449
0.437
0.427
0.494
0.638
0.688
0.978
0.427
0.473
0.458
0.451
0.431
0.427
0.378
0.387
0.372
0.349
0.427
0.558
0.520
0.544
0.491
'Data has been normalized.
 Method 7091

 3.0 Interferences
   3.2   The results obtained in this study
 document that the method is essentially
 free from interferences from 10 of the
 11 elements tested. Only molybdenum
 produced an interference, enhancing the
 absorbance at concentrations of 1000
 mg/L and above. Section 3.2 should be
 modified to read "Chemical and physical
 interferences can be  minimized  by
 optimizing the furnace AAS parameters
 and by using peak area instead of height
 in concentration calculations."

 4.0 Apparatus and Materials
   4.2   Instrument Parameters (general).
 It is recommended that  this section be
 titled:  "Instrument Parameters (with
 pyrolytically coated platform supported
 by an  uncoated graphite tube)."
   The   following   conditions   are
 recommended:
 4.2.1 Drying

 4.2.2 Ashing

 ,4.2.3 Atomizing

 4.2.4 Cleaning
   The following  rewording  in  the
 "NOTE:" is suggested:

     "NOTE: The above  instrument
     conditions are for a  Perkin-
     Elmer  HGA-500 graphite fur-
Time(s) Temp. (°C)
Ramp
5
5
0
1
Hold
25
25
4
1
200
900
2700
2700
                                 nace equipped with  an AS-40
                                 Auto Sampler.  Concentration
                                 values are based  on a 10 /A.
                                 injection with stop-flow at atom-
                                 ization and use of a pyrolytically
                                 coated graphite platform. Instru-
                                 ments made by different manu-
                                 facturers may require a differnt
                                 set of conditions."
                            9.0 Method Performance
                              The following  changes  are  recom-
                            mended to make the sections in Method
                            7090 and Method 7091 similar.
                              9.1  The performance characteristics
                            for an aqueous sample free of interfer-
                            ences are:

                                 Optimum concentration range:
                                  0.1 Aig/L-16//g/L
                                 Sensitivity: 0.4/ug/L
                                 Detection Limit: 0.08 fjg/L

                              9.2  In a single-laboratory analysis of
                            liquid and solid materials prepared  by
                            Method  3020  or  Method  3050, with
                            beryllium concentrations below 3 fjg/L,
                            the %RSD averaged  7 percent. For
                            samples with beryllium concentrations
                            above 3  percent,  the  %RSD was 2.3
                            percent. Spike recoveries  average  93
                            percent.
                              This report is in partial fulfillment of
                            contract  number  68-01-7159  by the
                            Environmental Research Center of the
                            University of Nevada, under the sponsor-
                            ship of the U.S. Environmental Protection
                                                            Agency. This report covers work  per-
                                                            formed during the period January 1987
                                                            to August 1987.

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     Vernon F. Hodge, Daniel A. Darby. Wendy E. Thompson, and Clifton L. Jones
       are with the University of Nevada, Las Vegas, NV 89119-9970.
     Thomas A. Hinners is the EPA Project Officer (see below).
     The complete report, entitled "A Single-Laboratory Evaluation of SW-846
       Methods 7090/7091  Determination  of Beryllium by Flame and Furnace
       Atomic Absorption Spectrophotometry," (Order No. PB 88-171 434/AS; Cost:
       $19.95, subject to change) will be available only from:
            National Technical Information Service
            5285 Port Royal Road
            Springfield, VA 22161
            Telephone: 703-487-4650
     The EPA Project Officer can be contacted at:
            Environmental Monitoring Systems Laboratory
            U.S.  Environmental Protection Agency
            Las Vegas, NV 89193-3478
    U.S. Government  Printing Office: 1988—548-158/67116
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S4-88/012
           0000329    f»S
                                           •«""

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