Archive for July, 2007

Red Wine Color Chemistry

Sunday, July 29th, 2007

Red Wine Color Chemistry   Ralph Obenauf, SPEX CertiPrep,


203 Norcross Ave.,  Metuchen, NJ

07920 USA     www.spexcsp.com

Why is red wine red? Because the skins of the grapes that it is made from are red.   For someone enjoying a glass of wine it is a simple answer to a simple question.  But to a chemist it is much more complicated than that.  There was an interesting article in Chemical and engineering news in May 2006 that reported on the research of James A, Kennedy Of Oregon State University, Corvallis, OR.   As we know the color of red wine is derived from the skins and changes as the wine ages.  The red color comes mainly from five anthocyanins differing in the substituent attached to the flavonoid of the 3-monoglucoside.  These anthocyanins are in equilibrium between the red flavylium cation form and the colorless hemiacetal form.  Another colorless bisulfite form is produced when sulfur dioxide or bisulfate is added as a preservative.  These colorless forms, obviously, reduce the desirable rich red colors.   After the wine is made, over a year or so reactions eliminate the original  anthocyanins to form other red colorants.  For instance the yeast metabolite, pyruvic acid, combines with the anthocyanins to form more stable brick-red flavylium vitisins from the blue-red anthocyanins.   Ref.  “Vintage Chemistry” Sophie L. Rovner, “Chemical and Engineering News”, 5/1/06, www.CEN-ONLINE.org 

Also see: www.newhope.com/nutritionsciencenews/NSN_backs/Dec_01/antho.cfm

Wines of “Obie’s Out of Bounds”

Tuesday, July 17th, 2007
# Wine type Blend Origin Barrel # # Gallons Crush Date Bottle Date Comments
14 Merlot   Chile 466 60 11-May-06 18-May-07  
13 Zinfindel    California 443 60 21-Sep-06 12-Jul-07  
12 Barolo 50%-40%-10% California 444 60 28-Sep-06 08-Jun-07 Nebbiolo, Barbera, Petite Sirah
11 Cabernet-Malbec 70%-30% Chile 466 60 29-Apr-06 18-May-07  
10 Ruby Cabnernet   California 66 53 23-Oct-05 03-Jun-06  
9 Chardonay   California NA 53 09-Oct-05 20-May-06 From Juice
8 Cabnernet-Syrah 70%-30% California 444 60 23-Sep-05 21-Jul-06  
7 Cabernet-Carmenere 70%-30% Chile 351 53 07-May-05 06-May-06  
6 Chardonay   California NA 53 05-Sep-04 NA  
5 Zinfandel   California 444 60 12-Sep-04 NA  
4 Cabernet-Malbec 70%-30% Chile 466 53 24-Apr-04 NA  
3 Cabernet-Merlot 70%-30% California 444 60 04-Oct-03 NA  
2 ChatoNeuf DuPape   California 444 60 28-Sep-03 NA Grenache, Cab, Mer, Cab Franc, Mal
1 Zinfandel   California NA 60 22-Sep-02 NA  

Calories in various wines

Tuesday, July 17th, 2007

The table below lists the approximate calories in an average (115ml or 4 oz) glass of wine.Wine can contain up to 15% alcohol by volume and alcohol contains 7 calories per gram.The more alcohol a wine contains the more calories, obviously.For comparison, on average, the same 115ml of beer has 50 calories, light beer 37 calories and non-alcoholic beer 20 calories, but no one I know stops at 115ml.Note that one gram of fat contains 9 calories and soda….forget it.I think I switched to wine to lose weight, dry red of course.Find more information on beer at: www.brewery.org/library/

 

Calories in wine

Wine Calories
Alcohol-free Wine 37 calories
Dry White 77 calories
Rose 82 calories
Dry Red 83 calories
Sparkling White 92 calories
Champagne 96 calories
Sweet Red 100 calories
Sweet White 103 calories
   
Fortified  
Sherry 140 calories
Martini Bianco 150 calories
Extra Dry Martini 150 calories
Bianco Vermouth 167 calories
Port 170 calories
Martini Rose 180 calories
Ginger Wine 190 calories
Martini Rosso 192 calories

Statistical Uncertainty Associated for the Certified Value of a Cr (VI) ICP RM

Monday, July 16th, 2007

Ralph Obenauf, PhD SPEX CertiPrep, Metuchen, NJ 08840, ROBENAUF@SPEXCSP.com 

www.SPEXCSP.com  

Abstract

Certified values of Reference Materials (CRM) are not useful unless accompanied by a stated and precisely defined uncertainty.  If certificates of analysis are examined, one often finds inconsistencies, misstatements and errors related to uncertainty (dispersion of the value that could reasonably be attributed to the measurand) and stability (change in value over time).  A precise understanding of measurement uncertainty on the part of the user is required as well as confidence that the reported uncertainty is calculated and defined correctly.  Your measured values are only as good the uncertainty of those results. 

 The paper will cover the evaluation of the total expanded uncertainty arising from all sources and covering all processes involved in determining the certified value of an ICP CRM.   This determination will be for a chromium (VI) reference material whose certified value was determined by titration against a standardized sodium thiosulfate solution which was in turn standardized against a potassium dichromate standard reference material, SRM.  Chromium (VI) is one of the six substances listed in the EU RoHS (Restriction of Hazardous Substances) directive 2002/95/EC requiring electronic equipment producers to limit these substances in their products.   

The above method was selected for discussion as it contains examples of many of the common procedures used in analytical determinations, wet or instrumental.  Therefore the uncertainty calculations here can be directly applied to other analytical methods to determine the statistical uncertainty of other common laboratory measurements such as those by ICP and ICPMS.  

Clean Laboratory Techniques for Trace Metals Analysis

Friday, July 13th, 2007

Dr. Ralph Obenauf and Nimi Kocherlakota,

SPEX CertiPrep, 203 Norcross Av, Metuchen, NJ 08840

www.spexcsp.com

ABSTRACT

The key issue in all chemical analysis is the integrity of the measurement.  Today’s instruments are capable of detecting metals at the ppb and ppt levels. However, having an instrument of this type in the lab will not be of much help if one does not minimize contamination and identify the remaining contaminants that are present in the lab environment, in reagents and in lab ware.

The presentation will cover the following issues and will cover various sources of contamination and tips on how to determine and prevent contamination.  While the discussion centers on the production of reference materials, the concepts are applicable to all your laboratory processes. 

               Starting materials used in the preparation of reference materials         Water         Acids         Storage containers         Laboratory environment         Other sources of contamination         Controlling contamination Starting Materials: Must be pure, stable and of known stoichiometry; it is also important that there are no (a minimum of) chloride, oxalate and sulfate ions present.          Pure, because impurities present can give rise to overlap of spectra, resulting in        incorrect calibration curves and therefore inaccurate results.         Stable because some materials are hygroscopic and some decompose upon                                heating.         Of known stoichiometry because some materials exist in multiple oxidation states of the primary metal.

         Abset of chlorides, oxalates and sulfates because if the starting materials are used in the preparation of multi-element standards, these ions could precipitate elements such as Ag, As,Au,Ba and  rare-earth elements.

Water:Water is the major component of an aqueous standard or a sample that is diluted. Therefore the overall quality/accuracy of analysis also depends on the quality of water that is used for trace metals analysis. One must use ASTM Type 1 water that meets the following specifications: Electrical resistivity at 18megohms, min TOC at 50 ug/L max, Sodium at 1 ug/L max, Chlorides at 1 ug/L max and total Silica at 3 ug/L max. Acids:Acids are used for the dissolution of materials and samples, digestions and dilutions.Contaminants present in acids can contribute to erroneous results. Storage Containers:Storage containers are bottles in which manufacturers store  and ship standards to customers.  These could also be the bottles in which the chemist in the lab stores his or her dilutions to be used in the future. Bottles come in various sizes, shapes and materials of construction.The contaminants that are present in the materials of construction can leach into the solutions and thus introduce contamination. Laboratory environment:There is no advantage in using high purity materials, acids, water etc, if the environment in which the standards or dilutions are made, and for that matter even the analysis that is performed, is not clean.A clean environment or clean room must meet the following requirements:          Environment of class 100 (less than 100 particles of 0.3microns per cubic meter).         Walls, ceilings and floors are sealed and are dust free.         HEPA filters mounted in the input stream of air.         Positive pressure in the clean area to flush out contamination.         No exposed metal parts. Other Sources of Contamination:         Sample preparation methods.         Sample to sample cross contamination.         Instrument sample introduction systems.         Environment in which the samples are prepared.         Materials that come in contact with the sample. Controlling Contamination:         Minimize exposure: Clean and cover the equipment after use.       Wear gloves.    Use metal free containers.     Separate lab ware into “low level” and “high level” lab ware:

“Low level” lab ware is used only for solutions that have metals present  below 1ppm concentration. “High-level” lab ware for solutions with greater than 1 ppm concentration of metals.

         Segregate lab ware for specific metals and ultra low concentration ranges.            Metals such as Pb and Cr are highly absorbed by glass but not by plastics.         For B and Si, avoid borosilicate glass. Use plastic, TFE or Quartz lab ware.         Samples containing low levels of Hg (PPB levels) should  be stored in glass or fluoropolymer containers because Hg vapors diffuse through Polyethylene bottles.         Use membrane filters instead of ashless filter paper. Ashless filter paper contains 20 trace elements at >1 ppm level.         Use “NOCHROMIX” instead of Chromic Acid to clean lab ware.         No jewelry, cosmetics or lotions.Cosmetics and lotions can introduce contaminants such as:Al, Be, Ca, Cu, Cr, K, Fe, Mn, Ti, or Zn into the samples.         Some hair dyes contain Lead acetate and eye makeup may contain Hg as a preservative.         Calamine lotion used for skin irritations is pure ZnO.

 Helpful Hints:         Test personnel, equipment and methods with QC samples.         Observe clean lab procedures and techniques.         Use reference materials that have not expired.         Make up and use only freshly prepared calibration standards.         Rerun samples using a different dilution factor.         Spike appropriate QC samples with expected levels of analytes or use standard additions.

         Carry blanks through all steps of an analytical procedure.

References:         Guidance in establishing Trace Metal Clean Rooms in Existing Facilities :USEPA 821-B-95-001         Accuracy in Trace Analysis : NBS Special Edition 422         Guide to Environment Analytical Methods :Roy-Keith Smith         Clean Manufacturing :A2C2; April 2003         Water Environment Laboratory Solutions :April/May 2003

         Sampling of sea and fresh water for the analysis of trace Metals; E.Helmers 1997

Uncertainty Calculations for the Certified Value of an Antimony Reference Material by ICP Using Three Point Calibration.

Friday, July 13th, 2007

Nimi Kocherlakota and Dr. Ralph Obenauf, SPEX CertiPrep, Inc., 203 Norcross Avenue, Metuchen, NJ 08840, USA, 

robenauf@spexcsp.com      www.spexcsp.com

Measurements can be made to determine if an instrument is running properly, to assess the value of a product/service, to accept or reject a product, or perhaps to comply with government regulations. To determine the quality of any measurement, a measure of uncertainty must be given along with the value.   In other words a measurement where there is no uncertainty listed is of unknown reliability and of limited value. As a user of analytical instrumentation, it is critical for one to know the accuracy of the calibration standards in use, and the uncertainty associated with the calibration curve itself.  Only then can one determine the confidence limit of one’s own data. This approach to standardize a method of reporting the certified value of a reference material determined by ICP uses a three point calibration curve.  A 1000 mg/L Antimony Certified Reference Standard was chosen to demonstrate how the statistical calculation of measurement uncertainty is performed.

Heavy Metals in Food Fish

Friday, July 13th, 2007

“Survey of Heavy Metal Contamination in Food Fish.”

Ralph Obenauf, Vanaja Sivakumar, SPEX CertiPrep, 203 Norcross Avenue, Metuchen, NJ 08840 

ROBENAUF@SPEXCSP.com    www.spexcsp.com

There has been a lot of publicity about mercury in large fish that are consumed by humans.  But mercury is not the only heavy metal to worry about, just the most “visible” and humans consume not only the flesh of the fish, but also fish oil supplements.  Our presentation will explore heavy metal contents in a variety of large food fish and fish oil diet supplements.  We will also use our found values to compare the government recommended daily intakes of these metals to the quantities of these metals consumed in a typical meal or dose of fish oil.  

Obie’s Laws

Friday, July 13th, 2007

Some borrowed and some new

  1. Work hard but play harder.  The rule of life that keeps one sane
  2. Don’t eat where you sleep. A rule of the road that makes you see new, different things
  3. On any trip reserve some time for yourself.  Again, this lets you see/experience new things of interest to you
  4. Don’t give away your luck.  If you win something or come by a windfall make use of it or reserve some of the winnings to invest in future chance
  5. Hot glass looks almost the same as cold glass.  This comes from my glass blowing days and will save pain
  6. Always look for what is missing in a situation, product or happening.  Those are the hard things to find, sort of like “omission versus commission”
  7. If something cannot go on forever it will stop.  Adapted from economist Herbert Stein, St. Pete Times 11/24/05 and has broad applicability
  8. Don’t count sunk costs.   From a marketing finance course but much broader: make decisions only on future potential from future investment of time/labor/cost, not based on past (sunk) investment
  9. Never wish away your life, enjoy every minute.  Sometimes you are bored or do not like a situation, but some day you will wish you had it back
  10. When estimating use the “pi factor”.   3.141 times or divided by what you expect in the direction less favorable to you and you will not be disappointed
  11.  If someone is nice to you but not nice to the waiter or cab driver…. they are not nice.  This is always true
  12. If you do something on time and at cost but it is not any good, no one will care about the cost or time.  However if your “something” exceeds expectations and works, no one will care if it is a bit late and somewhat over cost
  13.  If you do not fail or mess up sometimes, then you are not trying, doing or stretching far enough