İlker Aras Göçer measured nickel, arsenic, cadmium, antimony, mercury, thallium, and lead in ten baby wet wipes bought in Turkey. Each product was split into three matrices: the liquid squeezed from the sheet, the dried fiber, and the dried packaging. The printed results are in ppb of the solution that went into the ICP-MS. They are not milligrams per kilogram of wipe. Products are letter codes. This page does not name brands.
The thesis prose does not agree with itself on several maxima. Each figure below is tied to the sentence that prints it. A later sentence that prints a different maximum is kept, not averaged away. The bar charts on pages 50 to 54 are graphs. They are not a numeric table, and bar heights were not transcribed.
Key numbers
Limits of detection and quantification, Table 4, in ng/mL. The table header repeats LOQ. The row labels and the two columns are detection, then quantification. Below the quantification limit the thesis says it reported less-than LOQ.
| Analyte | LOD (ng/mL) | LOQ (ng/mL) |
|---|---|---|
| Pb | 0.04 | 0.12 |
| Hg | 0.13 | 0.43 |
| Cd | 0.03 | 0.11 |
| As | 0.03 | 0.11 |
| Sb | 0.03 | 0.10 |
| Tl | 0.04 | 0.09 |
| Ni | 0.06 | 0.20 |
Blanks of gloves, vials, filter, and syringe were below the quantification limit for every target metal.
Calibration, section 3.4.2: lead, cadmium, arsenic, antimony, thallium, and nickel, nine points from 0.1 to 50 ppb. Mercury, six points from 0.2 to 10 ppb. The thesis states R² above 0.999. Antimony figures of several hundred ppb sit above that 50 ppb top standard. Nickel at 53.40 ppb in one solution sits just above it. Those high figures are still printed. They are outside the calibration range the methods state.
Expressed solution
The solution was squeezed by hand. It was not put through the nitric-acid digestion used for fiber and packaging.
| Code | Analyte | Printed (ppb) | Where the thesis says it |
|---|---|---|---|
| I | Sb | 695.40 | Results paragraph and section 4.1. The English abstract rounds the same figure to 695.4 ppb. |
| G | Ni | 53.40 | Results paragraph, and section 4.2, as the highest solution nickel, in a mid-price product. |
| (no code) | Ni | 20.20 | Section 4.1, called a high solution nickel, with no code. This is not 53.40. |
| A | As | 11.80 | Results paragraph and section 4.2. Total arsenic. Not speciated. |
| D | Pb | 3.10 | Section 4.1 calls 3.10 ppb the solution lead. A later results sentence prints 3.10 ppb as a packaging maximum for code D, after it has already given packaging maxima of 3.20 and 3.16. The two packaging sentences conflict. The 3.10 ppb figure is kept with that conflict. |
| A | Cd | 0.20 | Results paragraph. Solutions A, B, and C only. |
| B | Cd | 0.20 | Results paragraph. Table 8 uses 0.20 ppb for solution B and does not print solution C. |
| C | Cd | 0.30 | Results paragraph. Higher than the Table 8 cadmium cell. |
| C | Hg | 2.90 | Results paragraph, highest solution mercury. Total mercury. Not methylmercury. |
| D | Hg | 2 | Table 8 only, written as “2 (Sol-D)“. This is not the 2.90 ppb sentence. The 2 ppb cell is not used as the result. |
Fiber
Fiber was dried, weighed at about 0.2 g, and digested. The number is still ppb in the measured solution. It is not a content in the dry fiber.
| Code | Analyte | Printed (ppb) | Where the thesis says it |
|---|---|---|---|
| D | Sb | 565.46 | Results paragraph, one of the two highest fiber antimony results. The English abstract uses 565.46 ppb as the fiber figure. |
| J | Sb | 537.86 | Results paragraph, the other fiber antimony figure called highest. |
| I | Sb | 476.69 | An unattributed sentence after the first nickel paragraph, and section 4.1, which treats 476.69 ppb as the high fiber antimony. It is lower than both 565.46 and 537.86. All three are printed. |
| I | Ni | 28.46 | Opening results sentence, called the highest fiber nickel. Section 4.1 repeats 28.46 ppb. |
| B | Ni | 10.53 | Later nickel sentence, called the highest fiber nickel. This is not 28.46. |
| F | Pb | 3.11 | Results paragraph, highest fiber lead. |
| J | Pb | 0.29 | Results paragraph, lowest fiber lead. |
| D | As | 0.34 | Results paragraph, highest fiber arsenic. Total arsenic. |
| D | Cd | 0.08 | Results paragraph, the only fiber cadmium called above the quantification limit. The quantification limit in Table 4 is 0.11 ng/mL. 0.08 is below that limit. The sentence and the table disagree. |
| A | Hg | 0.63 | Results paragraph. |
| B | Hg | 0.67 | Results paragraph, with A, the two highest fiber mercury results. |
| J | Tl | 0.70 | Results paragraph, highest thallium, and the only numeric thallium. Fabrics B and H are also said to contain thallium, without a number. Table 8 says thallium was below the quantification limit. That table cell is not used as the result. |
Section 4.2 says antimony was often in a band of 446 to 565 ppb and that the band did not follow price. It does not assign 446 ppb to a code.
Packaging
Packaging was dried and digested on the same program as the fiber. It is a package result. It is not evidence that the metal moved into the sheet or the liquid.
| Code | Analyte | Printed (ppb) | Where the thesis says it |
|---|---|---|---|
| H | Pb | 3.20 | Results paragraph, with J, the packaging lead maxima. |
| J | Pb | 3.16 | Results paragraph and Table 8. The English abstract uses 3.16 ppb as the packaging lead example. |
| D | Pb | 3.10 | A second packaging sentence, which conflicts with the H and J maxima. See the solution row. |
| C | Pb | 0.50 | Same second sentence, called the lowest measurable packaging lead. |
| B | Ni | 3.60 | Results paragraph. |
| C | As | 1.01 | Results paragraph, highest packaging arsenic. Total arsenic. |
| E | Cd | 0.13 | Results paragraph, highest packaging cadmium. Also detected in packaging A, B, C, H, and J, without individual numbers. |
| (some) | Cd | 0.12 | Section 4.1, “some samples,” which is not the 0.13 ppb maximum. |
| I | Sb | 0.03 | Results paragraph, with E, called the lowest packaging antimony. 0.03 ng/mL is the antimony detection limit, and the quantification limit is 0.10. |
| E | Sb | 0.04 | Results paragraph. Also at or below the quantification limit. |
Mercury in packaging is described as generally below the quantification limit. No packaging mercury number is printed in the results prose. Thallium outside fabrics B, H, and J is described as too low to measure.
Price groups, Table 2, are a grouping, not a quality ranking. Low: A, C, and E, under 0.45 Turkish lira per unit. Mid: B, G, H, and J, 0.45 to 1.00. High: D, F, and I, above 1.00. Section 4.2 says high antimony appeared in low-price A and C and in high-price D and I, and that price did not predict the metal. That conclusion is the thesis’s reading of its own charts. This page does not add a price effect.
Methods (brief)
Ten products were bought in Turkey and coded. The liquid was expressed by hand pressure into sterile containers. Gloves and containers were blanked before that step.
Fiber and packaging were dried in an oven for 30 to 60 minutes, the time depending on moisture, then cooled. About 0.2 g was taken on a balance readable to 0.001 g. Digestion used 65 percent nitric acid in a programmable digester, four steps: 120 °C and 1000 W for 8 minutes of ramp; 120 °C and 1000 W for 2 minutes; 180 °C and 1000 W for 8 minutes of ramp; 180 °C and 1000 W for 2 minutes. The methods say 10 mL of pure water was then added. They do not say the digest was made up to 10 mL, and they do not state the volume of acid. The solution was filtered at 0.45 µm. Three drops of nitric acid were added before injection, which the thesis describes as balancing pH.
The expressed lotion was not put through that digestion. A factor that converts the fiber digest into milligrams per kilogram is not printed, and it is not calculated here. The acid volume is missing, the mass is approximate, and the water was added rather than used as a stated final volume. Applying another paper’s dilution factor would invent a shared method.
The instrument is ICP-MS, controlled by Thermo Elemental Software version 131072, with a peristaltic pump and an autosampler. Section 3.3 says results are reported in µg/mL. The calibration, the limits, the results prose, and the English abstract use ppb, and the antimony discussion compares 695.40 ppb with a 6 ppb drinking-water figure. A reading of 695.40 µg/mL would be a different number by a factor of one thousand. The ppb figures are the ones the thesis discusses. They are not rescaled.
Chromium is named in the list of standard solutions on page 38. It is not in the calibration list, Table 4, or the results. No chromium result is inferred.
Arsenic is total arsenic. Mercury is total mercury. Antimony is not speciated.
Evidence fitness
The thesis is usable as a three-matrix measurement of ten coded products, in the unit it discusses. It cannot be placed on the same scale as a milligram-per-kilogram cosmetic limit, a Washington ppm component, or a per-liter digest from another laboratory. The solution, the fiber, and the package stay separate.
The thesis’s own limit table is not a crosswalk. Table 8 puts packaging lead of 3.16 ppb next to a REACH figure it writes as 0.05 in a column headed ppb, for children’s products, and next to an EPA drinking-water figure of 15 ppb. It puts solution antimony of 695.40 ppb next to an EPA drinking-water figure of 6 ppb. A drinking-water maximum is not a dermal limit for a wipe. The REACH lead restriction for articles that may be mouthed by children is a percent-by-weight rule, not a 0.05 ppb rule. Those comparisons stay inside the thesis.
Section 4.2 suggests that high antimony comes from a flame retardant. That is the thesis’s hypothesis. It is not established by a flame-retardant measurement in these wipes. A polyester-catalyst account in other papers is a different hypothesis. This thesis does not identify fiber type for the ten codes.
Limitations
There is no sample-by-sample numeric grid. The charts cannot be read back to a full matrix. Several maxima are printed twice, with different numbers. Cadmium at 0.08 ppb is called above a quantification limit of 0.11. Packaging antimony at 0.03 and 0.04 ppb is printed at or below the quantification limit. Antimony results above 50 ppb are outside the stated calibration. The final digest volume is not stated. No replicate count is printed for the sample results. The work is a thesis, not a journal article. It does not measure inorganic arsenic, methylmercury, chromium, tin, or aluminum, and it does not measure dermal absorption.
Related evidence
- Baby wipes
- Determination of heavy metals on the non-woven in wet wipes using ICP-MS
- Antimony
- Nickel
- Lead
Update history
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