Report
Non-aqueous
t o eliminate interference of protein. P r o t e i n m a y suppress or enhance calcium absorption, depending on t h e t y p e of flame used and t h e region of t h e flame where absorption is measured. If a rich air-acetylene flame is used t h e protein in serum nullifies t h e effect of phosphate present a n d t h e sample can be simply diluted with water. I t is safer t o add E D T A or s t r o n t i u m chloride. F o r highly a c c u r a t e measurements, proteins should be precipitated with trichloroacetic acid and strontium chloride added. T h e high phosp h a t e content of urine necessitates adding s t r o n t i u m or l a n t h a n u m salts for calcium determination. C h r o m i u m is t h e only u l t r a t r a c e m e t a l in blood t h a t has been determined a t physiological levels (30 ppb) by atomic absorption spectroscopy. N o r m a l levels of nickel, cadmium, and b i s m u t h have been determined in urine. C a d m i u m det e r m i n a t i o n s b y direct aspiration are somewhat high (0.05 p p m instead of 0.02 p p m ) due t o uncorrected light scattering by salts in t h e urine. T h i s technique is satisfactory for monitoring t h e c a d m i u m in urine of industrial workers exposed to c a d m i u m dust or fumes since t h e levels m a y be as high as 0.6 p p m . B y digesting t h e samples a n d extracting into M I B K , greater sensitivity for c a d m i u m is achieved. Nickel samples m u s t be digested t o determine n o r m a l levels. A s t a n d a r d additions method is used in t h e direct extraction method for bismuth. I r o n can be determined directly in serum diluted with water, b u t results a r e u n s a t i s f a c t o r y a t iron concentrations less t h a n 2.0 p p m due t o sensitivity limits and m a t r i x interferences. W h e n undiluted samples are aspirated, irreproducible results are obtained because of errors due t o v a r i a b l e flow r a t e and sample viscosity. T h i s can be circumvented by integrating t h e area u n der t h e absorption p e a k recorded during t h e aspiration of equal volumes (1 ml) of samples and s t a n dards. T h i s works satisfactorily only when t h e iron concentration is less t h a t 2.5 ppm, and samples with concentrations greater t h a n this are diluted. Absorption is decreased by 38 A
·
ANALYTICAL CHEMISTRY
with EASTMAN O r d e r by n a m e a n d E A S T M A N N u m b e r ( ) from whichever of these wellk n o w n laboratory supply houses customarily serves y o u : B&A CURTIN FISHER
HOWE & FRENCH NORTH-STRONG SARGENT-WELCH
V A N WATERS & ROGERS WILL
These same dealers supply the seven kinds of precoated EASTMAN CHROMAGRAM Sheet for TLC, sandwich-type CHROMAGRAM Developing Apparatus, and CHROMAGRAM Developing Jar. Acid Titrants Perchloric Acid (70%) (1604) in Acetic Acid (763) Perchloric Acid (70%) (1604) in p-Dioxane (2144) p-Toluenesulfonic Acid (984) in Chloroform (P337) Standards for Acids 1,3-Diphenylguanidine (1270) Phthalic Acid Monopotassium Salt (X538)also known as: potassium acid phthalate potassium biphthalate Base Titrants 2-Amino-2-(hydroxymethyl)-l,3propanediol (4833) in Methanol (467) also known as: tris-(hydroxymethyl)aminomethane Aniline (25) in Acetic Acid (763) Morpholine (P4324) in Acetonitrile (X488) Morpholine (P4324) in Methanol (467) Phthalic Acid Monopotassium Salt (538) in Acetic Acid (763) Phthalic Acid Monopotassium Salt (538) in Acetic Acid (763)/Benzene (777) Sodium Acetate (Anhydrous) (T227) in Acetic Acid (763) Tetrabutylammonium Hydroxide Titrant (25% in Methanol) (7774) Tetrabutylammonium Hydroxide Titrant (10% in Methanol) (P7774) in Benzene (777)/Methanol (467) Tetramethylammonium Hydroxide (10% in water) (1515) Tributylamine (1266), Iodomethane (164), Acetone (297), Ethyl Ether (997) Used to prepare triethylbutylammonium hydroxide which is used in Benzene (777)/Methanol (467) solution. Triethylamine (616) and 1-Iodobutane (56) Used to prepare triethylbutylammonium hydroxide solution which is used in Benzene (777)/Methanol (467). Standard for Bases Benzoic Acid (37) Indicators p-(p-Anilinophenylazo)benzenesulfonic Acid Sodium Salt (823) also known as: Tropaeolin 00 Brilliant Cresyl Blue (C1743) Clayton Yellow (1770) Crystal Violet (C1350) Curcumin (1179) 5-(p-Dimethylaminobenzylidene)rhodanine (2748) also known as: 4'-dimethylaminobenzalrhodanine
N,N-Dimethyl-m-nitroaniline(1208) also known as: m-nitro-N,N-dimethylaniline N,N-Dimethyl-p-phenylazoaniline(338) also known as: p-dimethylaminoa^obenzene 2,4-Dinitroaniline (1843) Ethyl Red (2155) Methyl Violet (1309) p-Naphtholbenzein (924) Neutral Red (C725) Nile Blue (C8679) 2'-Nitroacetanilide (2761) o-Nitroaniline (643) 2-Nitrodiphenylamine (3906) 4-(p-Nitrophenylazo)resorcinol (2484) also known as: azo violet Phenolphthalein (202) Pinacyanol (Chloride) (622) p-Phenylazophenol (417) also known as: p-hydroxyazobenzene 4-Phenylazodiphenylamine (1714) also known as: N-phenyl-p-aminoazobenzene Quinaldine Red (1361) Sudan III (C1754) Sudan IV (C1273) Thymolphthalein (1091) Thymolsulfonephthalein (753) also known as: thymol blue Solvents Acetic Acid (X763) Acetic Anhydride (4) Acetone (297) Acetonitrile « . 0 1 % H 2 0 , for non-aqueous titrations) (X488) 2-Aminoethanol (1597) also known as: ethanolamine (2-hydroxyethyl) amine Aniline (25) Benzene (Thiophene-free) (777) 2-Butanone (383) also known as: methyl ethyl ketone Benzonitrile (Aniline-free) (487) Butyl Alcohol (50) tert. -Butyl Alcohol (820) Butylamine (1261) Carbon Tetrachloride (Sulfur-free) (444) Chlorobenzene (70) Chloroform (Stabilized with Alcohol) (P337) Cyclohexane (702) Dichloromethane (342) Diethylene Glycol (2041) 2,5-Dihydrothiophene-1,1 -dioxide (9345) also known as: 3-sulfolene
