Reduction of Volatiles from Odorous Personal Care Ingredients with Honeywell Asensa DS 912 Odor Absorbing Zeolite

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1 SYNOPSIS Test results show that by adding Honeywell Asensa DS 912 odor absorbing zeolite at a 5% level to personal care ingredients which have malodors can substantially reduce the total volatiles measured by HS-GC-MS. Moreover, this technique can also identify and quantify specific chemical species among the total volatiles. Some of the specific compounds from the present ingredients, which are shown to be substantially reduced by DS 912, are known to have offensive odors. INTRODUCTION Undesirable odors from specific ingredients substantially reduce the materials acceptable to formulators of personal care products. Sometimes the most effective ingredient is deliberately avoided because of its unpleasant odor. Previous studies have shown that certain classes of zeolites are effective at absorbing unpleasant odors of bodily fluids. In many cases these zeolites can also be used to remove malodors form active ingredients. MATERIALS AND METHODS MATERIALS A variety of oleophilic and hydrophilic ingredients with disagreeable odors that are used in personal care products were obtained from commercial sources. These ingredients were analyzed with and the addition of Honeywell Asensa DS 912 crystalline absorbent at 5% loading. The DS 912 product is a proprietary odor-absorbing zeolite (INCI name: sodium silicoaluminate). METHODS Analysis of mostly organic volatiles was conducted by headspace (HS) gas chromatography- mass spectrometry (GC-MS). HS-GC-MS experiments were performed using 0.5g aliquots of each ingredient Page 1 of 10

2 sample as received, and then with 0.5g of ingredient sample with 25mg of DS 912 added to provide a 5% loading of the absorbent. The aliquots were sealed in 20 ml HS vials by means of aluminum crimped septa for analysis using an automated headspace analyzer. Each sample vial was heated for 30 min. at 50 C. Then, in sequence, each vial septum was punctured for sampling of headspace gases through a valving system for injection into a gas chromatograph. Organic volatile species were chromatographically separated on a DB-624 capillary GC column, which was interfaced with a mass spectrometer operating in electron impact mode. Characteristic GC peak retention times and MS fragmentation patterns allow characterization of the sometimes complex distributions of thermally volatile species from each personal care ingredient. Comparison of peak areas from ingredients analyzed with and DS 912 allowed a quantitative comparison of the relative reduction of volatiles. The sum of all observed peak areas from an ingredient provided the overall assessment of total volatiles reduction for that ingredient due to the DS 912 absorbent. RESULTS and DISCUSSION Quantitative comparison of HS-GC-MS patterns from eight different personal care ingredients, analyzed as received versus with the addition of 5% Honeywell Asensa DS912, showed various degrees of reduction for total volatiles. The total volatiles observed from each ingredient are compared as normalized percentages in Figure 1. These data show some substantial reductions in overall volatiles, e.g. for sulfur powder in olive oil or surfactants and sepia melan ink. The relative reduction of volatiles (predominantly organics) may be generally representative of odor causing chemicals. Moreover, HS-G C-MS can also provide additional information on absolute levels of volatiles from various ingredients, as well as specific chemical identification of individual volatile compounds or classes of compounds. These more detailed results can more specifically focus in on odor problems. Sulfur powder in olive oil shows an 85% reduction of total volatiles. HS-GC-MS (Figure 2) also specifically identified the observed volatile species as consisting of primarily sulfur-containing species and a series of aliphatic hydrocarbons. The major volatile peak is hydrogen sulfide (seen eluting at 1.56 min. in Figure 2), which has the characteristic odor of rotten eggs. The specific H 2 S peak from sulfur powder in olive oil is significantly reduced by 5% DS 912 (as seen in Figure 3). The other sulfurcontaining compounds and the aliphatic hydrocarbon species are also reduced, though the aliphatics (possibly associated with oil) would not have as major an effect on perceived odor. Page 2 of 10

3 Ethoxylated soybean oil shows only a 68% reduction of total volatiles. However, again, HS-GC-MS (Figure 4) can specifically characterize the chemistry of the volatiles distribution. The main volatiles from ethoxylated soybean oil consist of series of aliphatic hydrocarbons and aldehydes, as well as some aromatic species. An intense peak eluting at 2.06 min. was identified as acetaldehyde, which has a pungent odor. The specific acetaldehyde evolution from ethoxylated soybean oil is substantially reduced by 5% DS 912 (as seen in Figure 5). Other aldehydes and the hydrocarbons also appear reduced, essentially across the chromatogram. Tea tree oil at 1% in mineral oil shows little overall reduction in total volatiles. Even at this dilution in mineral oil HS-GC-MS (Figure 6) this ingredient shows very high absolute levels of volatiles. The dominant volatiles observed from tea tree oil are terpenes, particularly diterpenes. These major terpenes are not significantly affected by 5% DS 912 (see Figure 7). Chemicals in the diterpene class are indeed well known to be smelly. Some odors in this class of chemistry are generally considered pleasant (e.g. like lemon); while others may or may not be so agreeable (i.e. characteristic of turpentine). However, an early eluting, lower boiling series of minor aldehydes are substantially removed from the tea tree oil volatiles with the addition of DS 912 (see Figure 7). CONCLUSION The data shows that by adding Honeywell Asensa DS 912 odor absorbing zeolites at a 5% level to personal care ingredients, which are reported to have perceived malodors, can substantially reduce the total volatiles as measured by HS-GC-MS. Moreover, this technique can also identify and quantify specific chemical species among the total volatiles. In several examples HS-GC-MS shows DS 912 gave substantial reductions of particular chemical species, which are known to have bad odors. However, in one case (tea tree oil) little or no reduction was observed for the major distribution of diterpenes. Nevertheless, in that case, DS 912 still gave a substantial relative reduction in a chemically separate distribution of minor/trace aldehydes. Page 3 of 10

4 Reduction of Volatiles with Asensa TM DS % 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Castor Oil Avocado Oil Sulfur Powder in Oil Essential Fatty Acids Ethoxylated Soybean Oil Sulfur Powder in Surfactants Sepia Melan Ink 1% Tea Tree Oil in Min. Oil Figure 1. Reduction of volatiles with 5 % Asensa TM DS 912 odor absorbing zeolite Page 4 of 10

5 44000 TIC: D Figure 2. HS-GC-MS of sulfur powder in olive oil Page 5 of 10

6 44000 TIC: D Figure 3. HS-GC-MS of sulfur powder in olive oil plus DS 912 Page 6 of 10

7 80000 TIC: D Figure 4. HS-GC-MS of ethoxylated soybean oil Page 7 of 10

8 80000 TIC: D Figure 5. HS-GC-MS of ethoxylated soybean oil plus DS 912 Page 8 of 10

9 TIC: D Figure 6. HS-GC-MS of 1 % tea tree oil in mineral oil Page 9 of 10

10 TIC: D Figure 7. HS-GC-MS of 1 % tea tree oil in mineral oil plus DS 912 Page 10 of 10