Cannabis Proficiency Testing Material

Abstract

Provided is a proficiency testing material, and in more particular aspects, a cannabis proficiency testing material comprising: a plant substrate; and at least one chemical and/or microbial contaminant, wherein the at least one chemical and/or microbial contaminant is chemically or physically associated with the plant substrate. Methods of preparing the proficiency testing material and kits including the same are also provided.

Claims

1. A cannabis proficiency testing material comprising: a plant substrate; and at least one chemical and/or microbial contaminant, wherein the at least one chemical and/or microbial contaminant is incorporated into the plant substrate.

2. The cannabis proficiency testing material of claim 1, wherein the at least one chemical and/or microbial contaminant is a heavy metal.

3. The cannabis proficiency testing material of claim 2, wherein the heavy metal is selected from the group consisting of Arsenic (As), Cadmium, (Cd), Cobalt (Co), Chromium (Cr), Copper (Cu), Mercury (Hg), Manganese (Mn), Nickel (Ni), Lead (Pb), Thallium (Tl) and Zinc (Zn).

4. The cannabis proficiency testing material of claim 1, wherein the at least one chemical and/or microbial contaminant is a pesticide.

5. The cannabis proficiency testing material of claim 4, wherein the pesticide is selected from the group consisting of abamectin, acephate, aldicarb, acequinocyl, azoxystrobin, bifenazate, bifenthrin, boscalid, brodifacoum, bromodiolone, captan, carbofuran, carbaryl, chlorantraniliprole, chlordane, chlorfenapyr, chlorpyrifos, coumaphos, cyfluthrin, cypermethrin, daminozide, diazinon, dichlorvos, dimethoate, dimethomorph, difenacoum, difethialone, DDVP (Dichlorvos), ethoprop(hos), etofenprox, etoxazole, fenhexamid, fenoxycarb, fipronil, flonicamid, fludioxonil, imazilil, imidacloprid, malathion, methyl parathion, methiocarb, methomyl, mevinphos, metalaxyl, myclobutanil, naled, paclobutrazol, permethrin, piperonyl butoxide, PCNB, propiconazole, propoxur, pyrethrin, spinetoram, spinosad, spiromesifen, spirotetramat, spiroxamine, tebuconazole, thiacloprid, thiamethoxam, and trifloxystrobin.

6. The cannabis proficiency testing material of claim 1, wherein the at least one chemical and/or microbial contaminant is a residual solvent selected from the group consisting of n-hexane, n-heptane, n-pentane, 2-propanol, ethanol, acetone, acetonitrile, tetrahydrofuran, toluene, chloroform, carbon tetrachloride, benzene, m-xylene, o-xylene, p-xylene and methanol.

7. The cannabis proficiency testing material of claim 1, wherein the at least one chemical and/or microbial contaminant is a microbial contaminant.

8. The cannabis proficiency testing material of claim 7, wherein the microbial contaminant is a bacteria, fungi, mold, protozoa, yeast, or a toxin or byproduct of any one thereof.

9. The cannabis proficiency testing material of claim 1, wherein the plant substrate is a bud, flower, stem and/or leaf of a plant that is structurally similar to cannabis.

10. The cannabis proficiency testing material of claim 1, wherein the plant substrate is selected from the group consisting of Turnera diffusa (damiana), Nepeta cataria (catnip), Althaea cannabina and Althaea officinalis (marsh-mallow), Scutellaria (skullcap), Mentha (mint), members of the Cleomaceae family (spider plants), Hibiscus cannabinus (kenaf) and/or Humulus lupulus (hops).

11. A method of preparing a cannabis proficiency testing material comprising: combining a plant substrate and an aqueous solution comprising at least one chemical and/or microbial contaminant; and drying the plant substrate.

12. The method of claim 11, wherein the at least one chemical and/or microbial contaminant is a heavy metal.

13. The method of claim 12, wherein the heavy metal is selected from the group consisting of Arsenic (As), Cadmium, (Cd), Cobalt (Co), Chromium (Cr), Copper (Cu), Mercury (Hg), Manganese (Mn), Nickel (Ni), Lead (Pb), Thallium (Tl) and Zinc (Zn).

14. The method of claim 11, wherein the at least one chemical and/or microbial contaminant is a pesticide.

15. The method of claim 14, wherein the pesticide is selected from the group consisting of abamectin, acephate, aldicarb, acequinocyl, azoxystrobin, bifenazate, bifenthrin, boscalid, brodifacoum, bromodiolone, captan, carbofuran, carbaryl, chlorantraniliprole, chlordane, chlorfenapyr, chlorpyrifos, coumaphos, cyfluthrin, cypermethrin, daminozide, diazinon, dichlorvos, dimethoate, dimethomorph, difenacoum, difethialone, DDVP (Dichlorvos), ethoprop(hos), etofenprox, etoxazole, fenhexamid, fenoxycarb, fipronil, flonicamid, fludioxonil, imazilil, imidacloprid, malathion, methyl parathion, methiocarb, methomyl, mevinphos, metalaxyl, myclobutanil, naled, paclobutrazol, permethrin, piperonyl butoxide, PCNB, propiconazole, propoxur, pyrethrin, spinetoram, spinosad, spiromesifen, spirotetramat, spiroxamine, tebuconazole, thiacloprid, thiamethoxam, and trifloxystrobin.

16. The method of claim 11, wherein the at least one chemical and/or microbial contaminant is a residual solvent selected from the group consisting of n-hexane, n-heptane, n-pentane, 2-propanol, ethanol, acetone, acetonitrile, tetrahydrofuran, toluene, chloroform, carbon tetrachloride, benzene, m-xylene, o-xylene, p-xylene and methanol.

17. The method of claim 11, wherein the at least one chemical and/or microbial contaminant is a microbial contaminant.

18. The method of claim 17, wherein the microbial contaminant is a bacteria, fungi, mold, protozoa, yeast, or a toxin or byproduct of any one thereof.

19. The method of claim 11, wherein the plant substrate is a bud, flower, stem and/or leaf of a plant that is structurally similar to cannabis.

20. The method of claim 11, wherein the plant substrate is selected from the group consisting of Turnera diffusa (damiana), Nepeta cataria (catnip), Althaea cannabina and Althaea officinalis (marsh-mallow), Scutellaria (skullcap), Mentha (mint), members of the Cleomaceae family (spider plants), Hibiscus cannabinus (kenaf) and/or Humulus lupulus (hops).

21. A kit for proficiency testing of a cannabis diagnostic laboratory comprising a cannabis proficiency testing material comprising the cannabis proficiency testing material of claim 1.

22. A proficiency testing material comprising: a plant substrate; and at least one chemical and/or microbial contaminant, wherein the at least one chemical and/or microbial contaminant is incorporated into the plant substrate.

23. A method of proficiency testing comprising: analyzing test results obtained by a laboratory participating in a proficiency test for the cannabis proficiency testing material of claim 1 to determine whether testing performed by the laboratory meets standards set by a regulating or governing organization administering the proficiency test.

24. A method of proficiency testing comprising: analyzing test results obtained by a laboratory participating in a proficiency test of the proficiency testing material of claim 22 to determine whether testing performed by the laboratory meets standards set by a regulating or governing organization administering the proficiency test.

25. The method of claim 23, wherein the laboratory participating in the proficiency test monitors for a presence of chemical and/or microbial contaminants in a cannabis product or byproduct that result from tampering and/or adulteration of the cannabis product or byproduct by an individual(s).

Description

BRIEF DESCRIPTION OF THE DRAWING

[0016] FIG. 1 illustrates photographs and scanning electron micrographs (SEMs) of various plant substrate candidates for preparing cannabis proficiency testing materials of the present inventive concept.

DETAILED DESCRIPTION

[0017] The foregoing and other aspects of the present inventive concept will now be described in more detail with respect to other embodiments described herein. It should be appreciated that the inventive concept can be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art.

[0018] The terminology used in the description of the inventive concept herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the inventive concept. As used in the description of the inventive concept and the appended claims, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Additionally, as used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items and may be abbreviated as “/”.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this inventive concept belongs.

1. Proficiency Testing Materials

[0020] The inventive concept is a product that can be used as a proficiency testing (PT) sample for proficiency testing/external quality assessment (EQA) of laboratories that perform testing on products provided by, for example, but not limited to, the cannabis industry (both marijuana and hemp). Although referred to more particularly herein, in exemplary embodiments, for PT/EQA to assess and/or validate laboratories, and measurements made by such laboratories, monitoring products provided by the cannabis industry, the PT/EQA samples of the present inventive concept may be utilized in PT/EQA of laboratories involved in testing of, for example, any plant product or byproduct that may generally share physical characteristics, such as general physical appearance, leaf structure, color, morphology etc., with those of products and byproducts provided by the cannabis industry. The product may contain at least one chemical and/or microbial contaminant, which is/are connected with, including, contained, applied, coated, embedded, and/or incorporated in a plant substrate, at known concentrations. Thus, the at least one chemical and/or microbial contaminant may be chemically or physically associated with the substrate. The chemical and/or microbial contaminant may be any contaminant or pollutant that may need monitoring for assurance of quality and/or safety of the product or byproduct for, e.g., human and/or animal ingestion, consumption, inhalation, i.e., use. In some embodiments, the monitoring performed by a testing or diagnostic laboratory may be for assessing the presence of a contaminant or pollutant in the environment, such, uptake of contaminants/pollutants by, for example, plants, which include cannabis/marijuana plants, as a result of pollution produced by and contamination as a result of human industrial activity, for example, but not limited to, production of steel, paper, coal, energy production, construction, pollution resulting from travel/transportation, waste disposal, etc. In some embodiments, the monitoring by a testing or diagnostic laboratory may be for assessing the presence of contaminants, and the like, present in the plant, such as cannabis/marijuana plants, resulting from intentional tampering or adulteration by an individual(s). For example, the substances added from tampering with or adulteration of, e.g., “cutting” cannabis/marijuana products/byproducts, may include licit or illicit substances that may modify/modulate/alter the effects and/or appearance of cannabis/marijuana products/byproducts consumed by the user of the cannabis/marijuana product/byproduct, and that may be considered undesirable for consumption by and/or the safety of the user, and/or considered undesirable for consumption or safety by regulating organizations of the cannabis/marijuana product/byproduct. Potential adulterants of cannabis/marijuana products/byproducts may include, e.g., phytocannabinoids, synthetic cannabinoids, residual solvents, microorganisms, pesticides, heavy metals and mycotoxins. Examples of licit and illicit adulterants of marijuana that may be considered undesirable include, but are not limited to, methamphetamine, ketamine, fentanyl, cocaine, laundry detergent, phencyclidine (PCP), LSD, formaldehyde, perfumes, glass, and/or heroin, and other synthetic psychoactive substances, such as synthetic cannabinoids and cathinones. In some embodiments, contaminants may also include any poison, e.g., a heavy metal, such as, but not limited to, arsenic, cadmium, and/or lead, or pesticide, such as, but not limited to, carbofuran, and/or myclobutanil, as would be appreciated by one of skill in the art.

[0021] In some embodiments, the plant substrate may be the buds, flowers, stems, and/or leaves of a plant that is structurally and/or morphologically similar to cannabis. In some embodiments, the plant substrate is not a controlled substance, i.e., does not require a DEA license for sale, for example, from a vendor in one state to a recipient in another state, and thus can be distributed to any laboratory. In other embodiments, the plant substrate does not contain cannabinoids. In other embodiments, the plant substrate does not have a strong, distinct odor. In other embodiments, the plant substrate is widely available as organic/pesticide free due to its intended use for pets, for example, catnip. In other embodiments, the plant substrate has morphological similarities to cannabis based on general appearances and SEM images. In some embodiments, the plant material may be derived from, for example, Turnera diffusa (damiana), Nepeta cataria (catnip), Althaea cannabina and Althaea officinalis (marsh-mallow), Scutellaria (skullcap), Mentha (mint), members of the Cleomaceae family (spider plants), Hibiscus cannabinus (kenaf) and/or Humulus lupulus (hops). In an embodiment, the plant substrate may be catnip. In another embodiment, the plant substrate may be marsh-mallow.

[0022] In some embodiments, the contaminant connected, contained, applied, coated, embedded, and/or incorporated in the plant substrate is uniform or homogeneous, so that any particular amount of the material may be analyzed, for example, about 50 mg to about 100 mg plant material, to match the normal analytical method of a particular laboratory participating in a proficiency test.

[0023] The chemical or microbial contaminant, which is connected, contained, applied, coated, embedded, and/or incorporated into the plant substrate is not particularly limited. However, the chemical or microbial contaminant, in some embodiments, is a contaminant that may be found in cannabis and present a health and/or safety hazard to a user of a cannabis product.

[0024] Further examples of chemical contaminants include, in some embodiments, heavy metals, such as, but are not limited to, Arsenic (As), Cadmium, (Cd), Cobalt (Co), Chromium (Cr), Copper (Cu), Mercury (Hg), Manganese (Mn), Nickel (Ni), Lead (Pb), Thallium (Tl), and/or Zinc (Zn). In other embodiments, the chemical contaminant may be a residual solvent, examples of which include, but are not limited to, n-hexane, n-heptane, n-pentane, 2-propanol, ethanol, acetone, acetonitrile, tetrahydrofuran, toluene, chloroform, carbon tetrachloride, benzene, m-xylene, o-xylene, p-xylene and/or methanol. In other embodiments, the chemical contaminant may be a pesticide, further examples of which include, but are not limited to, abamectin, acephate, aldicarb, acequinocyl, azoxystrobin, bifenazate, bifenthrin, boscalid, brodifacoum, bromodiolone, captan, carbofuran, carbaryl, chlorantraniliprole, chlordane, chlorfenapyr, chlorpyrifos, coumaphos, cyfluthrin, cypermethrin, daminozide, diazinon, dichlorvos, dimethoate, dimethomorph, difenacoum, difethialone, DDVP (Dichlorvos), ethoprop(hos), etofenprox, etoxazole, fenhexamid, fenoxycarb, fipronil, flonicamid, fludioxonil, imazilil, imidacloprid, malathion, methyl parathion, methiocarb, methomyl, mevinphos, metalaxyl, myclobutanil, naled, paclobutrazol, permethrin, piperonyl butoxide, PCNB, propiconazole, propoxur, pyrethrin, spinetoram, spinosad, spiromesifen, spirotetramat, spiroxamine, tebuconazole, thiacloprid, thiamethoxam, and/or trifloxystrobin.

[0025] Examples of microbial contaminants may include, for example, bacteria, fungi, mold, protozoa, yeast, and/or toxins or byproducts from any one thereof. Bacteria include pathogenic bacteria, for example, Escherichia coli, Klebsiella, Salmonella, and Shigella, among others. Fungi and toxins or byproducts thereof include, for example, Alternaria, Aspergillus, Fusarium, Paecilomyces, Penicillium, Stachybotrys, and mycotoxins, such as aflatoxin, citrinin, fumonisins, ochratoxin A, patulin, trichothecenes, zearalenone, and ergot alkaloids, such as ergotamine.

2. Methods of Preparation

[0026] In some embodiments, the proficiency testing material may include a predetermined amount or concentration of a chemical or microbial contaminant uniformly contained, embedded and/or incorporated in the plant substrate. Any method as would be appreciated by one of skill in the art may be used to prepare the proficiency testing material, so long as the method provides a material which includes the chemical or microbial contaminant at a known, predetermined concentration that is uniformly contained, embedded and/or incorporated into the plant substrate. Uniform distribution of the chemical and/or microbial contaminant in the plant substrate may be useful in the proficiency testing material if, for example, a prepared batch of the proficiency testing material is divided into multiple test samples. uniform distribution of the chemical and/or microbial contaminant provides/assures there is a consistent amount of the chemical or microbial contaminant in each of the multiple test samples.

[0027] The proficiency testing material may be, for example, prepared by combining a plant substrate and a solution, e.g., by soaking the plant substrate in, adding the plant substrate to, or exposing the plant substrate to the solution. The solution, such as an aqueous solution, may be prepared containing, for example, metal salts and/or one or more pesticides, at an appropriate concentration to prepare a proficiency testing material containing the desired final product specifications. For example, a plant substrate, such as catnip buds or marshmallow leaf, may be soaked in an aqueous metal salt or pesticide solution for a suitable period of time, e.g., about 12 hours, about 16 hours, about 20 hours or about 24 hours, to ensure substantially complete adsorption of the desired contaminant in solution by the plant substrate, using, for example, about 3 mL of solution for each gram of plant substrate. The material may then be removed from the solution and dried on a non-absorbing surface, such as aluminum foil. The material is dried until the final weight is near the starting weight.

[0028] In other embodiments, the proficiency testing material may be prepared by spraying the plant substrate with a solution, such as an aqueous solution, prepared containing, for example, one or more metal salts, one or more pesticides, and/or microbial contaminants contained at an appropriate concentration in the solution to prepare a proficiency testing material with the desired final product specifications. The plant substrate may be sprayed with the solution more than once in order to achieve the desired product specifications. In some embodiments, the solution may be sprayed onto the plant substrate using a nebulizer. The plant substrate may be sprayed with a known amount of the solution that is adsorbed by the plant substrate that contains an amount of a metal salt(s), pesticide, and/or a microbial contaminant, such as bacterial spores, suitable to prepare a proficiency testing material having the desired final product specifications.

3. Methods of Use

[0029] The proficiency testing materials as described herein may be used in any type of proficiency testing scheme, for example, but not limited to, a scheme designed for monitoring and/or assessing participating testing facilities, such as cannabis testing facilities, e.g., testing and/or diagnostic laboratories that analyze plant products/byproducts, such as cannabis products/byproducts for, e.g., contaminants/safety of, for example, the cannabis products/byproducts for human or animal use/consumption. Types of proficiency tests include: blind proficiency tests, where the testing facility does not know it is being tested; external proficiency tests, i.e., a proficiency test obtained from and reported to a proficiency test provider external to the quality assurance system of the participant; internal proficiency tests, i.e., a proficiency test designed and administered within the quality assurance system of the participant; and open or declared proficiency tests, i.e., a proficiency test in which participants know they are being tested. Furthermore, in some embodiments, the proficiency testing material may be provided as part of a proficiency testing kit available to a testing or diagnostic laboratory, such as a cannabis testing or diagnostic laboratory participating in a proficiency test.

[0030] Having described various aspects of the present inventive concept, the same will be explained in further detail in the following examples, which are included herein for illustration purposes only, and which are not intended to be limiting to the invention.

Examples

1. Preparation

[0031] An aqueous solution is prepared by adding metal salts and/or pesticides at appropriate concentrations for the desired final product specifications. Catnip buds are soaked in the solution for 16 hours. 3 mL solution is used for each 1 g of plant material. This ensures almost complete absorption of the solution by the plant material. The plant material is then removed from the container and placed on aluminum foil (or any other non-absorbing surface) until dry. The material is dried until the final weight is near the starting weight.

[0032] Water uptake and analyte absorption efficiency factor are experimentally determined for each batch of plant material. Target analyte concentration (μg/g)=initial analyte concentration (μg/g)+stock concentration (μg/mL)×water uptake (mL/g)×analyte absorption efficiency factor. For example, one batch of PT containing catnip with 1 μg/g carbofuran, 0.5 μg/g myclobutanil, and 2 μg/g lead and arsenic was prepared by soaking 40 g of plant material in 120 mL of an aqueous solution containing lead (0.500 μg/mL), arsenic (0.500), myclobutanil (0.150 μg/mL) and carbofuran (0.260 μg/mL) overnight.

[0033] Current analytes included in the PT material were selected based on the cannabis testing requirements in California. Additional components from the same test categories (pesticides and/or metals) can be added using the same procedure. The final product can also be inoculated with microbial impurities and/or mycotoxins after the metals and pesticides are incorporated.

2. Characteristics

[0034] FIG. 1 depicts photographic and SEM characterization of the morphologies of cannabis and various potential plant substrates for the proficiency testing material. The plant substrates used in the preparation of proficiency testing materials are catnip (Nepeta cataria) buds and marshmallow (Althaea cannabina). Catnip buds as a plant substrate can provide the following advantages: [0035] it is not a controlled substance (federally or by any state) [0036] does not contain potentially interfering cannabinoids [0037] does not have a strong distinct odor [0038] contains similar structural components to cannabis bud/flowers (as opposed to many available plant products, such as teas, that contain mainly leaves) [0039] is widely available as organic/pesticide free due to intended use for pets [0040] it has morphological similarities to cannabis based on SEM images (See, FIG. 1) [0041] tests with metals incorporation demonstrated adequate homogeneity (See, Tables 1 and 2)

[0042] Other non-controlled plants could be used as well. The main desired characteristic for any plant material used in cannabis testing would be that it contains flower/buds to mimic authentic cannabis samples and has adequate homogeneity of absorption. Candidate plant substrates include those depicted in FIG. 1.

[0043] Evaluation of the incorporation of various heavy metals into the plant substrate proficiency testing material is shown by the results shown in Tables 1 and 2. Table 1 shows the incorporation of Pb and the natural abundances of As, Cd, and Hg into two different sources of catnip and marshmallow leaf. Table 2 shows the incorporation of As and Pb into catnip. These tests with heavy metal incorporation demonstrated adequate homogeneity.

[0044] The foregoing is illustrative of the present inventive concept and is not to be construed as limiting thereof. The invention is defined by the following claims, with equivalents of the claims to be included therein.

TABLE-US-00001 TABLE 1 Metal incorporation results for lead in different plant substrates. As Cd Hg Pb 12171-75-01.1 33.0 205 22.7 1473 Marshmallow Leaf As and Cd show the 12171-75-01.2 28.3 201 <DL 1442 Marshmallow Leaf sample is fairly 12171-75-01.3 30.6 188 <DL 1532 Marshmallow Leaf uniform. 12171-75-01.4 30.5 192 <DL 1378 Marshmallow Leaf 12171-75-01.5 32.2 207 <DL 1778 Marshmallow Leaf Average 30.9 198 22.7 1521 Standard Deviation 1.8 8.4 n/a 154 10% 12171-76-01.1 31.6 155 <DL 1398 Organic Catnip As and Cd show high 12171-76-01.2 24.7 46.4 <DL 2358 Organic Catnip variability in sample. 12171-76-01.3 25.1 44.5 <DL 2330 Organic Catnip 12171-76-01.4 <DL 39.0 <DL 2315 Organic Catnip 12171-76-01.5 34.2 43.3 <DL 2636 Organic Catnip Average 28.9 65.7 <DL 2207 Standard Deviation 13.6 50.2 n/a 471 21% 12171-79-01.1 68.6 <DL <DL 3041 Kitty Catnip As shows sample has 12171-79-01.2 78.4 <DL <DL 2940 Kitty Catnip some uniformity 12171-79-01.3 62.6 <DL <DL 2376 Kitty Catnip issues. If you ever 12171-79-01.4 85.4 <DL <DL 3589 Kitty Catnip need to spike Cd, 12171-79-01.5 76.9 <DL <DL 3280 Kitty Catnip this would be the Average 74.4 <DL <DL 3045 Standard Deviation 8.9 n/a n/a 450 15% Pb avg without 2376 3212 288.8707148 0.089926489 .sup.aCalculated as: instrument result (ng/mL) *digestion volume (10 mL)/mass of sam  DL for As, Cd, Hg, and Pb = 20 ng/g Nominal mass for each sample was 50 mg. Same digestion procedure as last time. indicates data missing or illegible when filed

TABLE-US-00002 TABLE 2 Metal incorporation results for arsenic and lead in catnip. As % Recovery Pb % Recovery Blank 0.009 n/a −0.016 n/a 10 9.974 99.74 10.33 103.3 20 19.76 98.8 20.21 101.05 50 49.93 99.86 50.11 100.22 Check1 20.14 100.7 19.4 97 Blank1 0.022 n/a 0.017 n/a CFS-1 17.5 15.73 CFS-2 16.61 14.34 CFS-3 19.55 15.1 CFS-4 17.51 14.08 CFS-5 18.62 14.03 Check2 20.79 103.95 19.23 96.15 Blank2 0.027 n/a 0.015 n/a Weight, g As μg/g Pb μg/g 0.0997 CFS-1 17.5 1.76 15.73 1.58 0.0953 CFS-2 16.61 1.74 14.34 1.50 0.0996 CFS-3 19.55 1.96 15.1 1.52 0.1003 CFS-4 17.51 1.75 14.08 1.40 0.0986 CFS-5 18.62 1.89 14.03 1.42 Ave. 1.82 1.49 STDEV 0.101 0.0714