Paper spots

Alternatively, acidified urine can be collected on a filter paper. The urine is preserved with 20% HC1 as described above. Filter paper strips (3 x 5 cm filter paper backing, cat. No. 165-0921, Bio-Rad) are dipped into urine to 1 cm below the upper edge. Excess urine is wiped off, and the filter is left to dry at room temperature. Urinary filter paper spots are then cut into small pieces, shaken in 3 ml of water for 15 min at room temperature, and sonicated for 5 min at room temperature. The extracts are filtered through an Ultrafree-MC filter with 10-kDa cutoff (Millipore, USA) at 2000g for 10 min at room temperature. The clear supernatant is analyzed by HPIC. 

Blau N, Matasovic A, Lukasiewicz-Weldechowicz A, Heizmann CW, Leumann E (1998) Simultaneous determination of oxalate, glycolate, citrate, and sulfate from dried urine filter paper spots in a pediatric population. Clin Chem 44 1554-1556... 

Berry HK, Berry MA, Spinanger J (1960) A paper spot test useful in study of Hurler s syndrome. J Lab Clin Med 55 136-138... 

First, 100 parts of m-dinitrobenzene is added to 1,000 parts of water at 90 C contained in a reducer fitted with a reflux condenser and a propeller-type stirrer. Upon emulsification, 245 parts of sodium sulfide (9HaO), dissolved in a minimum of water, is gradually run in. The dinitro compound is gradually reduced to m-nitroaniline, the end point being determined by the formation of a definite black streak when ferrous sulfate solution is added to filter paper spotted with some of the reducer liquor. 

Test soln placed on filter paper spotted with reagent (2). After drying the spot is treated with reagent (1)... 

Co-register the liquid paper spots between the optical image and the video image of the mass spectrometer. 

Detection of / -aminobenzenesulfonamide derivatives is similar to that of aromatic amines, either with / -dimethylaminobenzaldehyde (p. 349), or by diazotization with vapors of nitrogen oxides and coupling (p. 349). Roux reagent is also suitable 10 g of sodium nitroprusside are dissolved in 100 ml of water, and the solution is mixed with 2 ml of 33% NaOH and 5 ml of 0.1 N KMn04, and is filtered after spraying the paper, spots of various colors appear, which are observed in visible or ultraviolet light. 

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