Mass-spectrometric multielement analysis of copper and copper-base alloys, with electrical detection

Tnlrmro,Vol. 24, pp. 625-631. Pergamon Press, 1977. Printed in Great Britain.

MASS-SPECTROMETRIC MULTIELEMENT ANALYSIS COPPER AND COPPER-BASE ALLOYS, WITH ELECTRICAL DETECTION E. VAN HOYE,R.

GIJBELS

and F.

OF

ADAMS

Department of Chemistry, University of Antwerp (U.I.A.), Universiteitsplein B-2610 Wilrijk, Belgium

1,

(Received 22 February 1977. Accepted 6 April 1977)

Summary-Relative sensitivity coefficients have been determined for 21 elements in copper and its alloys, with iron as an internal standard, by spark-source mass-spectrometry with electrical detection and magnetic peak-switching. Twenty calibration standards ranging from pure copper to 60%~copper alloys were used. The sensitivity coefficients measured appear to be independent of the elemental concentration and are obtained with a mean precision of 15%.

Accurate quantitative analysis by spark-source massspectrometry requires determination of relative sensitivity coefficients by analysis of calibration standards. In this work the relative sensitivity coefficients of a number of elements in copper and copper alloys are determined by spark-source mass-spectrometry with electrical detection. The sensitivity coefficient Sa, for an element x in a given matrix is defined as

where y is the reference element. Iron was preferred to copper as the reference element. The matrix element is more homogeneous and is more accurately

certified but it has no low-abundance isotope; the large matrix ion-currents may cause instability of the electron multiplier’ and saturation of the output signal. Moreover, with iron as a reference, the results can be compared directly with those obtained in a previous study of the steel matrix.2 Several authors have published experimentally determined sensitivity coefficients for the analysis of copper with photoplate detection.3 The coefficients reported in this paper were determined by using electrical detection and magnetic peak-switching. The previous study’ for steel samples showed that this mode of operation is more precise than the photographic method of analysis. Although the mass resolution with electrical detection is considerably lower than with photoplate detection it is adequate because the copper spectra are not too complicated. Nevertheless, in order to detect possible spectral interferences, the complete mass spectra were first recorded with photoplate detection. EXPERIMENTAL

The mass spectrometer was a radio-frequency sparksource. double-focusing instrument with Mattauch-Herzog geometry (JMS-01 BM-2, JEOL, Tokyo) equipped with an electrical detection system (MS-ED-01).

Samples

Spark-source mass-spectrometry requires very homogeneous samples because very small amounts of material are consumed. Copper reference materials especially prepared for spark-source mass-spectrometry are not available. The samples used here were selected from standard reference materials intended primarily for optical emission and X-ray spectrometry and were tested for homogeneity. The samples cover a wide range of composition from very pure copper to 60%-copper alloy (brass). They were chosen in such a way that the Ss values of as many elements as possible could be determined in several samples. Five copper-base alloys, available from the National Bureau of Standards, Washington, DC. were chosen as reference materials: SRM 1101 and 1102 (Cartridge Brass B and C), SRM 1106 and 1108 (Naval Brass A and C) and SRM 1121 (Beryllium Copper). They are wrought materials in the form of discs, 32 mm in diameter and 19 mm thick. Table 1 lists the certified concentrations. According to the certificates, these values are not expected to deviate from the “true” concentration by more than +l in the last significant figure reported; for a subscript figure, the deviation is not expected to be more than k5. The values in brackets are not certified, but are given for information. The standard deviation of the certified values was assumed to be half the specified uncertainty of kl or +5 in the last significant figure. From the three series of graded dilute copper alloys prepared by Johnson Matthey Ltd., London, for use in spectrochemical analysis, eight reference materials were analysed. These standards contain the impurity element listed in Table 2. These samples are available in the form of rods 3 mm in diameter and 90 mm long, except for sample CA 4 (1.6 x 100 mm). The analysis reports do not give information on the precision of the results listed, but the same assumptions were made as for the NBS data. From the Canada Centre for Mineral and Energy Technology, Ottawa, four commercial-purity copper rods (SSC 14) were used. They are intended as reference materials for spectrographic purposes and are in the form of hotrolled rods, 8 x 300 mm. Table 3 gives the recommended values and the corresponding standard deviations. In addition, copper samples containing standardized platinum contents of 100, 12 and 1.2 ppm w/w from the BCR (Community Bureau of Reference, Commission of the European Communities, Brussels) were analysed. They were prepared by successive dilutions of platinum in copper by means of high-frequency levitation melting.4 The’ 625

626

E. Table

Element

1. Composition

VAN

HOYE, R. GJJBELS and F. ADAMS

of the NBS copper-base

NBS-SRM 1106

NBS-SRM 1108

Cartridge Brass B

Cartridge Brass C

Naval Brass A

Naval Brass C

CO Ni

0.004, 0.011

0.005 0.004

0.025 0.050

0.025 59.0* 40.0.

0.033 64.9, 34.4*

0.74

0.39

0.01

0.032

0.063

(0.002)

Bi

0.0W4

O.fXQ,

0.05

Table

1.89 0.07 0.11 (O.coS) (O.cil2)

0.020

2. Composition

CI Ga Ag

0.003 0.004 0.006

Sn Sb

0.005 0.0043

Pb Bi

0.005 0.008

of the Johnson

Matthey Series CB CB 0

CB 1

Element

0.0018 0.0021 0.0020

o.Ocu33 0.0005 0.@306

Si MII Fe

0.02 0.018

Be P

0.0015 0.0010

O.OCQ6 0.0005

CO

0.049 0.046 0.023

0.052

0.011 0.02

Zn AS

0.033

0.015

0.0024 0.0023

o.OcHl7 o.ooo9

Se Te

of the master

Ni

Table 3. Composition of the certified commercial purity copper rods from the Canada Centre for Mineral and Energy Technology value and standard deviation, ppm ssc-2

7 0.5 0.8 7 0.3

32 f 3+1 16 & 1.2 f 2.6 f 14 f 10 f 10 * 5.8 + 1.2 * 6il 0.10 f

ssc-3 7 5 0.6 0.8 3 1 2 0.7 0.5 0.04

40 f 9 48 f 8 15 +4 5*2 3.9 * 0.7 16 +4 12 f 2 2*1 2.5 ?r 0.6 5+2 0.59 * 0.01

cc

I

cc

3

cc

5

0.0300 0.0230

o.lw65 0.0050

0.0012 0.0008

0.0230 0.015

O.M)60 0.004

0.0015 0.001

0.016; 0.0150

0.0040* 0.0055

0.0008* 0.0015

alloy.

electron multiplier was Johnson Matthey high-purity platinum wire (diameter 0.5 mm) with a total metallic impurity content lower than 10 ppm. Sample preparation. Two cylindrical rods (2 mm diameter) were machined from the samples; the ends were flattened to a thickness of 1 mm as proposed by Franzen and Schuy.’ The sparking surfaces were ground flat and the electrodes etched in dilute nitric acid (pa.), washed

Recommended

%w/w

Series CC

Element

discs with a diameter of 10 mm and a thickness of 1.5 mm. They have been investigated by several techniques such as neutron, photon and charged-particle activation analysis, atomic-absorption spectrometry, emission spectrography, X-ray fluorescence analysis, isotope dilution methods and spark-source and low-voltage discharge mass-spectrometry. The weighted mean of all analyses is specified as 98.5 + 0.1, 11.75 f 0.03 and 1.18 f 0.01 ppm, respectively. The sample used for testing the dynamic range of the

+ f f + f

alloy standards,

CA 6

samples are

39 f 7 18 k 3 33 + 8 1.2 * 0.5 7+2 19 k6

dilute copper

CA 4

from the dilution

ssc-1

(0.W 0.081 0.29, 0.012 91.4, (0.01) (0.005)

Series CA CA 3

55 2.6 4.6 65 1.2

Beryllium Copper CA-172

0.0+X5 0.037

0.005 72.8~ 27.1, 0.004 O.cQlO 0.004, 0.036 0.005 OSQO,

Fe Ni ZII AS Se Ag Cd SII Sb Te Pb Bi

NBS-SRM 1121

O.OWQ, 0.0007 (O.ao2) 0.004,

0.013 69.6, 30.2, 0.009 0.003 0.005, 0.016 0.012 0.0015

Pb

%w/w

O.ooOS~ O.OCQ6 (0.005) o.0020

CU ZIl As AC Cd SKI Sb Te

Element

materials,

NBS-SRM 1102

P Cr MII Fe

* Calculated

reference

NBS-SRM 1101

Be ::

Element

alloy standard

ssc-4 50 25 30 2.8 2.9 21 19 21 11 1.4 16 0.23

f 9 k4 f 1 f 0.5 f 0.8 +5 + 3 f 3 * 1 * 0.4 k 1 f 0.05

with distilled water and rinsed in acetone (p.a.). They were sparked off at least 10 min before starting the measurements.

Mass-spectrometric procedure

The instrumental parameters selected were identical to those used for the analysis of iron and steel samples,’ except for the following. The width of the collector slit was adjusted to 350 pm instead of 250 pm in order to reduce the effect of instability of the magnetic field. No extra interferences were caused by the resulting mass-resolution degradation, as the spectra were rather simple. With the sparking conditions as for steel samples, it was impossible to obtain stable sparking for a sufficient length of time as the copper and brass electrodes soon made contact and fused together. Therefore the “Variac” setting which controls the input to the radiofrequency oscillator was lowered to 2.5 kV, which corresponds to a spark-source voltage of about 40 kV. Nevertheless, for the brass samples, stable sparking remained difficult. RESULTS

Linearity

AND DISCUSSION

of the electron-multiplier

response

Unlike iron, the matrix element in this study has no low-abundance isotope and therefore the matrix ion-current up to which the electron multiplier response remained proportional to the input current was first established. For all the isotopes of a wellchosen matrix element, the collector current was integrated until a 1-nC charge had been collected at the total ion-beam monitor. Each individual current integration took about 15 sec. Platinum was selected since it has 6 stable isotopes with abundances ranging

627

Analysis of copper and copper-base alloys

from 0.013 to 33.8%. It was shown that none of these

isotopes suffered interference from impurities. It was possible to measure integrated multiplier currents between 3 x lo- l3 and lo- 6 C. To cover this range, the measurements had to be carried out at several electron-multiplier voltages. Figure 1 shows that saturation occurs at an integrated current of 3 x 10m7 C. This corresponds to a multiplier current of about 2 x lo-' A and a dynamic range of 106. Consequently, it is difficult to use copper as an internal standard because it cannot be measured with the same multiplier voltage as impurities at the ppmlevel. Iron was therefore used as the reference element. As the iron concentration is above 30 ppm in every sample, it is possible to measure copper us. iron. Qualitative

.’

I 0. I

I

Isotopic

Fig. 1. Electron-multiplier

abundance,

I IO

%

response at different multiplier voltages.

analysis

The interferences detected in the spectra are listed in Table 4. The trailing superscript refers to the positive charge of the ion; the plus signs of the charge superscripts are omitted since all ions are of positive charge. The charge superscript is omitted entirely for species having a single positive charge. Interferences below 15% were corrected for by using interferencefree isotopes of the interfering element. Nearly all elements had one or more isotopes that were free from interference. Only beryllium in the samples NBS-SRM 1101, 1102 and JM CC5, aluminium in NBS 1101, silicon in NBS-SRM 1101 and

Table 4. Interferences in copper and copper alloy spectra

Element Be Al Si

Cr Fe

Ni

Isotope 9 27 28 29 30 54 54

NBS NBS NBS NBS NBS NBS

56 57

NBS 1106 NBS 1101, 1102, 1106, 1108; SSC-2,4 all samples NBS 1106. 1108

58 58

60

r20s,2

61

Ztl Se Cd SD Te

62

“4Sn’

64 64, 66

6’Zn

77 80, 82 112, 114, 112, 114, 122, 124 120, 122, 123 125 126, 128,

116 116 124

130

Interfered in sample but corrected by use of the stxcies in brackets

Interfered in samole

background Cu, CuH: “Cu C, ‘-Cu N CuOH Sll Cd Te Sll ‘=Sb t CU:

* Charge transfer in electric field

1101, 1101 1101. 1101, 1101, 1121

1102; JM CC 5 11102 1102; JM CB-0, 1102; JM CB-0,

’

I I

NBS 1106, 1108; SSC 1.2 NBS 1101, ssc-1,4 NBS 1101, ssc 1,2,4 all samples NBS 1121;

1102, 1106, 1108, 1121; 1102, 1106, 1108, 1121; except JM CBO, 1 JM CC 3,s; SSC-1.4

JM CC 3,s; SSC l-4 all samples all samples NBS 1101, 1102; SSC-2,4 NBS 1101, 1102; SSC-1,4 NBS 1101, 1102; SSC-1,4 NBS 1101, 1102; SSC-1,4 NBS 1101: SSC-2,4 all samdes

JM CC 1 3 (“Cu’) NBS 110; (57Fez) NBS 1121, JM CB 0 1 (I’Fe’) NBS 1121 (61Niz) NBS 1121 (“Ni’) SSC-1 3(=Cr) (52Cr,‘“1Cdfj SSC-2 4(‘“Cd’) SSC-l:3(“9S”“)

SSC-2,4

NBS 1101 1102 (“%n’)~ NBS 1121’ SSC-1 3(-“Fe L’9Sn’). S’SC_24(;4.56.5?Fe 11LCd2,‘L1~Sn*) NBS 1101, 1102, 1121; SSC-3,4(“9Snz)

’

E.

628

VAN

HOYE,

R. GUBELS

1102, nickel in NBS-SRM 1106 and 1108, selenium in the BCR-samples and tellurium in NBS-SRM 1102 and SSC-2,3 and 4 could not be determined by using magnetic peak-switching under the conditions used in this work. The sensitivity coefficients of these elements were determined in several of the other samples. Brass and beryllium copper standards The relative sensitivity coefficients of the elements certified by the National Bureau of Standards in brass and beryllium-loper samples were dete~ned. Six channels were available on the instrument used; one was used for the internal standard, the others for isotopes of the elements to be measured. For each isotope, 8 successive integrations were carried out before switching to the next isotope. The integrated monitor charge was about 1 nC. The entire sequence was repeated at least 10 times and the experiments were carried out in 2 or more groups over a one-month period, The results were averaged and the corresponding relative standard deviation was calculated from

100 (Ci- C)’ ------% C !I n-1 where Ci is an individual concentration, c the mean concentration and n the number of analyses. All interference-free isotopes were used Whenever more than one isotope was available, the weighted average concentration and the corresponding standard deviation was calculated from

and F. Ao~lrrs

where N is the number of reference materials used. The S, values were calculated by using the data in Table 1. The results are summarized in Table 5. The standard deviations listed take into account only the precision of the measurements and not the uncertainties in the certified concentrations. The average relative standard deviation for all elements is 13% compared with 10% found previously for iron and steel samples. This might be attributed to the less homogeneous distribution of some elements and to the fact that with the brass samples it was difftcult to obtain stable sparking conditions. Dilute copper alloy standards The same experiments were performed on 8 dilute copper alloys from Johnson Matthey. As iron was not certified in series CA and CC, copper was used as the internal standard and the &-values were recalculated by using the S, value of copper us. iron, as determined in the samples from series CB. The results are listed in Table 6 and the average relative standard deviation for all elements is 10%.

s=i-

c =

c(ci/s?) W/S?)

and

Certijied commercial-purity

copper rods

To extend the composition range of the copper samples studied to lower concentrations, four reference materials from the Canada Centre for Mineral and Energy Technology were analysed. They consist of high-purity copper doped with some impurities. The results are listed in Table 7. The average relative standard deviation for all elements is 13%, suggesting that these materials are less homogeneous than the Johnson Matthey samples. Radermacher and Beske6 also found indications of poor homogeneity, even with a low-voltage discharge ion-source mass-spectrometer.

Table 5. Experimentally determined S, values for brass and beryllium copper for the NBS standards* Element

SRM 1101 Sn

s, %

SRM 1102 SK

s, %

SRM 1106 SK

5. %

SRM 1108 &

s. %

Be Si Al P Cr Mll Fe CO Ni

0.65

8

0.75

10

CU ZIl AS Ag

0.55 1.0 2.2 2.8

10 5 20 15

0.60 0.95 2.3 1.5

6 7 17 12

Cd Sn Sb Te Pb Bi

2.4 2.9 2.6 3.1 3.7 2.2

25 lb 21 25 17 17

2.5 2.0 2.7

15 21 20

4.3 1.8

25 21

1.6

21

1.6 1

10 -i

1.2 1.6

25 15

1.32

6 -1

1.4

0.53 0.75

8 -1

6 6

1.29

0.61 0.87

7 -1

10 5

SRM 1121 S,

s, %

0.68

6

0.92 1.31 (1.6) (1.25) (20)

z 7

0.81 0.70

1: 6 6

(1.7) 0.65

l;J

(2.5)

10

2.8

15

2.7

17

3.2

13

3‘4

20

3.2

20

(4.5)

20

* Where no value is indicated, either a certified concentration or an interference occurs.

is unavailable

629

Analysis of copper and copper-base alloys Table 6. Experimentally determined S, values for the Johnson Matthey copper alloy standards Sample number

Ga

Cr

CA-3 CA-4 CA-6

SR

8, %

1.8 1.76 2.2

6 5 6

SR 2.2 1.7 2.3

SE

s, %

10 9 8

1.9 2.5 2.8

7 10 9

2.6 2.7 2.7

s. %

SR

s. %

Mll

Si SR

s. %

S,

CB-0 CB- 1

1.02 1.1

5 9

1.70 1.85

cc-1 cc-3 cc-5

0.58 0.62

8 9

1.5 1.8 1.4

5 5

13 11 15

1 1

The BCR has been sponsoring the development of standard reference materials for noble metals. Three of them, oiz. copper containing 100, 12 and 1.2 ppm platinum, and the “blank” copper were analysed. First a panoramic analysis was made of the “blank” copper sample by using magnetic scanning. Five scans, each taking 40 min for the total mass range, were recorded. The average concentrations found are listed in Table 8, column 2. They are corrected with the sensitivity coefficients shown in Table 10. In Table 7. Experimentally determined S, values for the commercial-purity copper rods from the Canada Centre for Mineral and Energy Technology

Pb BI

1 0.67 0.55 1.03 1.7 2.9 1.5 2.5 2.4 3.4

7 5 9 16 19 11 12 19 15

l 0.70 0.56 0.90 1.8 2.5 1.4 2.2 2.3 2.6 -

12 6 12 14 17 10 15 14 21 -

1 0.60 0.58 0.92 2.6 1.5 1.4 2.1 2.7 -

2.5 2.0

20 17

2.7 1.9

24 21

2.5 1.7

15 21 ~

1 0.63 0.61 0.98 3.0 2.9 1.7 2.6 2.4 3.2 -

6 4 9 9 11 6 9 7 16 -

21 16

3.5 2.0

14 13

9 4 l; 17 ”

6 8 7

Bi

Pb &%

SR

13 19 17

SQ.

3, %

SR

s. %

18 19 21

2.0 2.4 2.0

13 15 12

10 12 8

3.3 4.3 4.5

S.

s, %

S.

0.88 0.94

4 7

0.75 0.74

5 4

0.79 0.81

3 3

2.5 2.2 1.9

15 11 16

2.4 2.0 1.6

14 12 15

3.6 3.3 3.0

10 9 14

CO

_ -

1.01 1.12 0.85

Sb S, %

SR

Fe

Copper samples with standardized platinum content

Fe Ni CU ZII AS Se Ag Cd SIl Sb Te

Sll

AS s, %

3.4 2.9 4.4

Ni

e

CU s, %

SR

s, %

column 3, the results found by Beske7 by using lowvoltage discharge mass-spectrometry are listed. The values between square brackets are not corrected with a sensitivity factor. Column 4 shows the values found by Govaerts et al.’ by neutron-activation analysis. The concentrations of some elements, namely Fe, Ni, Cu, As, Ag, Sb and Pb, are known from independent analysis7** They could be used for determining the sensitivity coefficients and were therefore studied by use of the more precise peak-switching mode of operation. The sensitivity coefficients obtained are listed in Table 9 and are in good agreement with those listed in Tables 5, 6 and 7. The three copper samples with a standardized platinum content were also analysed by using peakswitching. The concentrations found were 87 + 7, 10 f 1 and 1.0 f 0.1 ppm, corresponding to sensitivity coefficients of 0.88, 0.87 and 0.85 respectively. The average standard deviation is loo/,, which indicates a homogeneous distribution of platinum. It was noted, however, that when measurements were made immediately after etching, values of the platinum concentration twice as high were obtained. The initial results were erratic and decreased to the values given above. These correct values were found when no chemical treatment was carried out or when the electrodes were ground flat with silicon carbide paper

Table 8. Panoramic analysis of the “blank” copper from BCR with magnetic scanning, ppm* Element C N 0 F Na Mg Al Si S Cl Ca

This workt [O.l9] Cl61 C6ll [0.15] Cl.21 [0.50] 0.28 1.4 Cl21 CO.521 Cl.91

B&X’S CO.41 8.6 39 10.31 CO.41 CO.31 CO.41 E81

Element

This workt

Beske’$

Cr Mn Fe CO Ni AS

0.80 0.61 intern. stand. 0.37 1.4 1.4 10 0.39
[3.2] 0.8 6.7

Ag Sb h Pb Bi

CO.31 1.4 1.5 8.3

1.3 7.4 0.35

3.3

Values between brackets not corrected with a relative sensitivity coefficient. t Spark-source mass-spectrometry, electrical detection (magnetic scanning). 3 Low-voltage discharge source mass-spectrometry, photoplate detection. $ Instrumental neutron-activation analysis.

*

T*L. 24,110-c

630

E. VAN HOYE,R. GLIBELS and F. ADAMS

Table 9. Experimentally determined S, values for the “blank” copper from BCR, with Fe as the internal standard Element Fe Ni CU AS Ag Sb Pb

Uncorrected centration,

conppm

Relative standard deviation, %

6.1 1.4 85 x lo4 3.3 21 1.1 8.9

Sensitivity coefficient

_

1 1.00 0.85 2.5 2.8 3.2 2.7

8 6 15 11 17 16

after etching. The erroneous results after chemical etching suggest that platinum may be redeposited onto the etched surface. Average sensitivity coejkients for the analysis of cop per and copper alloys

The errors in the data given in Tables l-3 differ widely. The standard deviation of the &-values was obtained from:

where a refers to the value measured by mass-spectrometry, and b and b’ to the certified concentration of the analysed element and the reference element respectively. The weighted averages of all the relative sensitivity coefficients determined above and their standard deviation were then calculated from

and

The results are listed in Table 10. The overall mean relative standard deviation obtained is 15%. This figure is signiticantly affected by the uncertainties of the certified concentrations of the reference materials, especially those of the SSC-standards. As can be seen from Table 3, the average relative standard deviation for these samples is 20% for the internal standard and 22% for the other elements used.

The relative sensitivity coefficients found here are in good agreement with those found for iron and steel sampleq2 except for manganese and copper which show a significantly higher sensitivity in iron than in copper. The higher sensitivity of manganese in iron samples was also reported by other authors, e.g., by Jaworski and Morrison9 who suggested that it may be affected by the strong matrix lines on either side. A systematic survey for all the elements investigated shows’ no evidence that the Sa values change with concentration. In all cases the slope of the most probable straight line drawn through the data points does not significantly differ from zero. By way of example, Fig. 2 shows the Sa values for phosphorus, nickel, zinc and arsenic plotted vs. their concentration in the samples. CONCLUSIONS The relative sensitivity coefficients for 21 elements in copper and copper alloy samples for spark-source mass-spectrometric analysis with magnetic peakswitching varied from 0.63 for beryllium to 3.3 for tellurium and lead. They appeared to be independent of the elemental concentration at widely differing concentration levels and matrix compositions. Except for copper and manganese, they are in good agreement with those determined for iron and steel samples. The precision of the peak-switching measurements for the samples from Johnson Matthey and the BCR was the same as that found for iron and steel samples in a previous study, viz. 10% relative standard deviation. For the copper alloys obtained from the National Bureau of Standards and for the commercial-purity coppers from the Canada Centre for Mineral and Energy Technology a 13% r.s.d. was obtained. With the NBS brass samples this was probably due to the fact that it proved difficult to obtain stable sparking conditions. The Canadian samples seemed less homogeneous. The overall precision of the experimentally determined relative sensitivity coefficients is 15% r.s.d. compared with 10% for the iron and steel samples. This is mainly due to the larger uncertainties of the certified values of the reference materials used.

Table 10. Weighted average relative sensitivity coefficients for the analysis of copper and copper alloys (Fe: SR= 1). Number of reference materials, used, N

Number of reference Element Be Al Si P Cr Mll CO Ni CU Zn Ga Overall mean

materials, 0.63 + 1.3 * 0.98 + 1.6 + 1.7 + 1.5 * 0.86 f 0.72 f 0.66 f 1.0 f 2.0 f relative

0.08 0.2 0.08 0.2 0.2 0.1 0.06 0.07 0.05 0.1 0.2 standard

used N

3 2 3 6 4 7 3 10 12 12 3 deviation: 15%

Element AS Se Ag Cd Sll Sb Te pt Pb Bi

2.3 2.0 2.0 2.4 2.6 3.1 3.3 0.9 3.3 2.0

i 0.6 f 0.4 f 0.3 f 0.5 * 0.5 f 0.7 f 0.5 f 0.2 f 0.8 j.e 0.5

IO 7 11 4 12 10 5 3 13 9

631

Analysis of copper and copper-base alloys

Concentration,

% w/w

Fig. 2. Effect of ~n~ntration on the relative sensitivity coefficients of some elements in copper and copper ahoy samples. (The concentration-axis for Zn is displaced by 1 decade to the low concentration side). RE~RE~~~ I. R. J, Gonzemius and H. J. Svec, in Trace Analysis by Mass Spectrometry, A. J. Ahearn, ed, p. 135. Academic Press, New York. 1972. 2. E. Van Hoye, F. Adams and R. Gijbels, Ta~a~t~ 1976, 23. 789. 3. H. Farrar IV, in Trace Analysis by Mass S~ectro~try, A. J. Ahearn, ed., p. 239. Academic Press, New York, 1972. 4. J. Van Audenhove and J. Joyeux, NW!. Instr. methods, 1972, 102, 409.

5. 3, Fmnzen and K. D. Schuy, Advan. Mass Spectry., 1968, 4, 449.

6 L. Radenmacher J&h,

and H. E. Beske, Ber. Kernforsch.

No. 1325, 1976.

7. H. Beske, private communication. 8. A. Govaerts, R. Gijbels and J. Hoste, Anal. Chim. Acta, 19x,79,

139.

9. J. F. Jaworski and G. H. Morrison, Anal. Chem., 1974, 46, 2080.